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CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation of application Ser. No. 10/941,487, filed on Sep. 15, 2004, entitled “Handheld electronic device including preferred network selection, and associated method”, now allowed, which is incorporated by reference herein.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates generally to handheld electronic devices and, more particularly, to a handheld electronic device that enables a user to establish a prioritized list of preferred networks to be used in roaming situations. The invention also relates to an improved method of establishing a prioritized list of preferred networks to be used by a handheld electronic device in roaming situations.
2. Description of the Related Art
Numerous types of handheld electronic devices are known. Examples of such handheld electronic devices include, for instance, personal data assistants (PDAs), handheld computers, two-way pagers, cellular telephones, and the like. Such handheld electronic devices are generally intended to be portable and thus are relatively small.
Many handheld electronic devices include and provide access to a wide range of integrated applications, including, without limitation, email, telephone, short message service (SMS), multimedia messaging service (MMS), browser, calendar and address book applications, such that a user can easily manage information and communications from a single, integrated device. These applications are typically selectively accessible and executable through a user interface that allows a user to easily navigate among and within these applications.
Many handheld electronic devices include wireless telephone and data (e.g., email, SMS, Internet) functionality. As is known in the art, wireless services, such as telephone and data services, are provided by way of an air interface involving radio frequency (RF) communications between wireless enabled equipment, such as a handheld electronic device described above, and one or more networks of land based radio transmitters or base stations. Each such network is commonly referred to as a public land mobile network (PLMN). PLMNs interconnect with other PLMNs and the public switched telephone network (PSTN) for telephone communications or with Internet service providers for data and Internet access.
In order to use wireless communications functionality, a user must subscribe with a wireless service provider or operator. The subscription permits the user to utilize the PLMN operated by the service provider or operator (referred to as the “home PLMN”). As is known in the art, roaming is a service offered by PLMN operators which allows a subscriber to use his or her wireless enabled equipment while in the service area of another operator (and outside of the user's home PLMN). Roaming requires an agreement between operators of technologically compatible systems to permit customers of either operator to access the other's PLMN. Service providers or operators typically charge a higher per-minute fee for calls placed outside their home calling or coverage area (the area serviced by their PLMN).
As is also known in the art, devices, such as handheld electronic devices, that include wireless functionality, such as telephone and data functionality, are provided with a subscriber identity module card (SIM card). A SIM card is a small printed circuit board that contains subscriber details, including data that identifies the user to the service provider, security information, and memory for a personal directory of numbers. In addition, the SIM card stores a pre-set, prioritized list of particular PLMNs to be used by the device in roaming situations. The particular PLMNs included in the list are normally based on the marketing preferences of a particular operator. However, as will be appreciated, different PLMNs have differing charges associated with them and offer different levels of reliability and service quality. Thus, a user may desire to use PLMNs other than those pre-stored in the SIM card and/or use PLMNs in a different order of priority than that specified in the SIM card based on issues of cost, reliability, and service quality, among others. Thus, there is a need for an improved handheld electronic device that enables a user to establish a prioritized list of preferred PLMNs to be used in roaming situations.
SUMMARY OF THE INVENTION
An improved handheld electronic device and an associated method enable a user to selectively establish a prioritized list of preferred PLMNs to be used in roaming situations. As a result, a user is able to select particular PLMNs based on issues of PLMN cost, reliability, and service quality, among others.
These and other aspects of the invention are provided by a wirelessly enabled handheld electronic device including an input apparatus, a communications subsystem, a display, a processor, and a memory storing one or more applications executable by the processor. The one or more applications are adapted to display a listing of one or more known networks for which network information is stored in the memory, scan for one or more available networks, which are networks available for use in conducting wireless communications in the area in which the handheld electronic device is currently located, and display a listing of the available networks. The applications are also adapted to enable the entry of information relating to one or more manually entered networks. Furthermore, the applications are adapted to (1) enable the addition of one or more preferred networks to a preferred network list wherein the preferred networks are one or more of: (i) certain of the known networks selected from the listing of known networks, (ii) certain of the available networks selected from the listing of available networks, and (iii) the manually entered networks; (2) enable the assignment of a priority value to each of the preferred networks; and (3) utilize one or more of the preferred networks for performing wireless communications when the handheld electronic device is in a roaming situation, wherein the preferred networks are utilized in a priority order that is based on the priority value assigned to each of the preferred networks.
The communications subsystem may include a SIM card, wherein the applications are further adapted to store the preferred network list in the SIM card. The preferred network list also preferably includes network information for each of said preferred networks, such as the MNC and MCC for each of the preferred networks. The handheld electronic device may also include a thumbwheel that may be used to scroll up and down for data selection purposes.
Preferably, the preferred network list is displayed in a display order corresponding to the priority order. In one case, the priority value of a first one of the preferred networks is a highest priority, and the priority value of a second one of the preferred networks is a lowest priority, and the priority order is sequential beginning with the first one of the preferred networks and ending with the second one of the preferred networks. The applications may be further adapted to enable the movement of a selected one of the preferred networks on the display to create an altered display order, wherein the priority value assigned to one or more of the preferred networks is changed such that the priority order corresponds to the altered display order. In addition, the one or more applications may be further adapted to enable the deletion of a selected one of the preferred networks on the display to create an altered display order, wherein the priority value assigned to one or more of the preferred networks is changed such that the priority order corresponds to the altered display order.
According to another aspect of the invention, a method of establishing a prioritized list of networks to be used by a handheld electronic device in roaming situations is provided. The method includes displaying a listing of one or more known networks upon request of a user of the handheld electronic device, with each of the known networks having network information stored by the handheld electronic device, scanning for one or more available networks upon request of the user, with each of the available networks being available for use in conducting wireless communications in an area in which the handheld electronic device is currently located, and displaying a listing of the available networks. The method further includes receiving information relating to one or more manually entered networks when input into the handheld electronic device by the user. Finally, the method includes adding one or more preferred networks to a preferred network list, the preferred networks being one or more of: (i) certain of the known networks selected from the listing of known networks, (ii) certain of the available networks selected from the listing of available networks, and (iii) the manually entered networks, and assigning a priority value to each of the preferred networks, wherein one or more of the preferred networks are utilized for performing wireless communications when the handheld electronic device is in a roaming situation in a priority order that is based on the priority value assigned to each of the preferred networks.
BRIEF DESCRIPTION OF THE DRAWINGS
A full understanding of the invention can be gained from the following Description of the Preferred Embodiment when read in conjunction with the accompanying drawings in which:
FIG. 1 is a front view of an improved handheld electronic device in accordance with the invention;
FIG. 2 is a block diagram of the handheld electronic device of FIG. 1 ; and
FIGS. 3 through 20 are exemplary views of a portion of the display of the handheld electronic device of FIGS. 1 and 2 that illustrate a routine or routines for enabling a user to selectively establish a prioritized list of preferred PLMNs to be used in roaming situations according to the invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
An improved handheld electronic device 4 in accordance with the invention is depicted generally in FIGS. 1 and 2 . The handheld electronic device 4 includes a housing 8 , a display 12 , an input apparatus 16 , and a processor 20 ( FIG. 2 ) which may be, without limitation, a microprocessor (μP). The processor 20 is responsive to inputs received from the input apparatus 16 and provides outputs to the display 12 . While for clarity of disclosure reference has been made herein to the exemplary display 12 for displaying various types of information, it will be appreciated that such information may be stored, printed on hard copy, be computer modified, or be combined with other data, and all such processing shall be deemed to fall within the terms “display” or “displaying” as employed herein. Examples of handheld electronic devices are included in U.S. Pat. Nos. 6,452,588 and 6,489,950, which are incorporated by reference herein. The handheld electronic device 4 is of a type that includes a wireless telephone capability which, as will be described in greater detail below, enables a user to selectively establish a prioritized list of preferred PLMNs to be used in roaming situations in accordance with the invention. As used herein, the terms “phone” and “telephone” shall refer to any type of voice communication initiated and conducted over a wired and/or wireless network.
As can be understood from FIG. 1 , the input apparatus 16 includes a keyboard 24 having a plurality of keys 26 , and a rotatable thumbwheel 28 . As used herein, the expression “key” and variations thereof shall refer broadly to any of a variety of input members such as buttons, switches, and the like without limitation. The keys 26 and the rotatable thumbwheel 28 are input members of the input apparatus 16 , and each of the input members has a function assigned thereto. As used herein, the expression “function” and variations thereof can refer to any type of process, task, procedure, routine, subroutine, function call, or other type of software or firmware operation that can be performed by the processor 20 of the handheld electronic device 4 .
As is shown in FIG. 2 , the processor 20 is in electronic communication with memory 44 . Memory 44 can be any of a variety of types of internal and/or external storage media such as, without limitation, RAM, ROM, EPROM(s), EEPROM(s), and the like, that provide a storage register for data storage such as in the fashion of an internal storage area of a computer, and can be volatile memory or nonvolatile memory. The memory 44 further includes a number of applications executable by processor 20 for the processing of data. The applications can be in any of a variety of forms such as, without limitation, software, firmware, and the like, and the term “application” herein shall include one or more routines, subroutines, function calls or the like, alone or in combination.
As is also shown in FIG. 2 , processor 20 is in electronic communication with communications subsystem 45 . Communications functions for handheld electronic device 4 , including data and voice communications (wireless telephone), are performed through communications subsystem 45 . Communications subsystem 45 includes a transmitter and a receiver (possibly combined in a single transceiver component), a SIM card, and one or more antennas. Other known components, such as a digital signal processor and a local oscillator, may also be part of communications subsystem 45 . The specific design and implementation of communications subsystem 45 is dependent upon the communications network in which handheld electronic device 4 is intended to operate. For example, handheld electronic device 4 may include a communications subsystem 45 designed to operate with the Mobiltex™, DataTAC™ or General Packet Radio Service (GPRS) mobile data communication networks and also designed to operate with any of a variety of voice communications networks, such as AMPS, TDMA, CDMA, PCS, GSM, and other suitable networks. Other types of data and voice networks, both separate and integrated, may also be utilized with handheld electronic device 4 . Together, processor 20 , memory 44 , and communications subsystem 45 may, along with other components (having various types of functionality), be referred to as a processing unit.
In FIG. 1 , the display 12 is depicted as displaying a home screen 43 that includes a number of applications depicted as discrete icons 46 , including, without limitation, an icon representing a phone application 48 , an address book application 50 , a messaging application 52 which includes email, SMS and MMS applications, and a calendar application 54 . In FIG. 1 , the home screen 43 is currently active and would constitute a portion of an application. Other applications, such as phone application 48 , address book application 50 , messaging application 52 , and calendar application 54 can be initiated from the home screen 43 by providing an input through the input apparatus 16 , such as by rotating the thumbwheel 28 and providing a selection input by translating the thumbwheel 28 in the direction indicated by the arrow 29 in FIG. 1 .
FIGS. 3 through 17 are exemplary depictions of display 12 of handheld electronic device 4 that illustrate a routine or routines performed by processor 20 for enabling a user to selectively establish a prioritized list of preferred PLMNs to be used in roaming situations according to the invention. By utilizing the invention, a user of handheld electronic device 4 is able to override the list of particular PLMNs to be used by the handheld electronic device 4 in roaming situations that is pre-stored in the SIM card forming a part of communications subsystem 45 by establishing and storing a user selected and prioritized list of PLMNs to be used by the handheld electronic device 4 in roaming situations. In the particular embodiment shown in FIGS. 3 through 17 , this list is called the “My Preferred Network List.”
FIG. 3 is an exemplary depiction of display 12 showing an “Options-Network” screen 50 generated by an operating application of handheld electronic device 4 which provides a user with information and options relating to the PLMNs used or to be used by handheld electronic device 4 . As seen in FIG. 3 , menu 52 may be accessed from “Options-Network” screen 50 in a known manner using input apparatus 16 . Menu 52 includes an item 54 entitled “My Preferred Network List.” When a user desires to create a prioritized list of PLMNs to be used by handheld electronic device 4 in roaming situations according to the invention, the user first selects item 54 . When a user does so, a “Preferred Network List” screen 56 as shown in FIG. 4 is displayed on display 12 . “Preferred Network List” screen 56 displays a prioritized listing 58 of PLMNs selected by the user as described herein to be used by handheld electronic device 4 in roaming situations. As seen in FIG. 4 , the listing 58 is initially empty. To add a PLMN to the listing 58 , the user accesses menu 60 in a known manner and selects item 62 entitled “Add Network.” Next, as seen in FIG. 6 , “Add Network” screen 64 is displayed to the user on display 12 . At this point, the user has three options to choose from for adding a PLMN to the listing 58 . Each option is described below.
In the first option, a user can manually add a PLMN to the listing 58 by entering identifying information for the PLMN into the data fields provided on “Add Network” screen 64 using input apparatus 16 . In particular, to add a particular PLMN to the listing 58 , the user must enter the mobile network code (MNC) for the PLMN at field 66 , the mobile country code (MCC) for the PLMN at field 68 , and the priority the user wishes to assign to that PLMN at field 70 . The respective priorities assigned to the PLMNs listed on listing 58 determines the order in which the PLMNs are to be used by handheld electronic device 4 , if available, in roaming situations.
In the second option, the user can add a PLMN to the listing 58 by selecting the PLMN from a group of “known networks” stored in memory 44 of handheld electronic device 4 (the MNC and MCC is stored for each such “known network”). To do so, the user accesses menu 72 in a known manner and selects item 74 entitled “Select From Known Networks.” Next, as seen in FIG. 8 , “Find” screen 76 is displayed on display 12 . “Find” screen 76 includes a listing 78 of all of the “known networks” stored by memory 44 of handheld electronic device 4 . A user may then identify for selection a particular PLMN from listing 78 by scrolling down listing 78 in a known manner using input apparatus 16 or by typing a portion of or all of the name of the PLMN using input apparatus 16 as shown in FIG. 9 . Once a particular PLMN has been identified, a user may then select the PLMN for inclusion in the listing 58 by accessing menu 80 in a known manner and selecting item 82 entitled “Select Network” as shown in FIG. 10 . When this is done, “Add Network” screen 64 is displayed on display 12 as shown in FIG. 11 , and information for the PLMN is automatically provided in fields 66 (MNC) and 68 (MCC), as well as field 84 , which is the name of the PLMN. The user must then enter information into field 70 using input apparatus 16 to establish the priority to be assigned to the PLMN. Once all of the information has been entered, the selected PLMN may be saved to the listing 58 by accessing menu 72 in a known manner and selecting item 86 entitled “Save” (which item was added to menu 72 because listing 58 is no longer empty; compare FIG. 7 ) as shown in FIG. 12 . As seen in FIG. 13 , when saved, the selected PLMN appears in listing 58 . When all the desired PLMNs have been added to and prioritized in the listing 58 , listing 58 may be saved to the SIM card forming part of communications subsystem 45 by accessing menu 60 in a known manner and selecting item 88 entitled “Save” (which item was added to menu 60 because listing 58 is no longer empty; compare FIG. 5 ) as seen in FIG. 14 . Note that, for illustrative purposes, FIG. 14 assumes that additional PLMNs have been added to the listing 58 , and thus the listing 58 shown in FIG. 14 includes additional PLMNs not shown in FIG. 13 . Once the listing 58 is saved to the SIM card, it, and not the pre-stored list described above, is used to determine which and in what order PLMNs are to be used by handheld electronic device 4 , if available, in roaming situations. In other words, listing 58 overrides the pre-stored list of PLMNs provided with the SIM card.
In the third option, the user can add a PLMN to the listing 58 by selecting the PLMN from a group of “available networks,” which handheld electronic device 4 is able to locate from its current location using communications subsystem 45 and a known network scanning procedure. To do so, the user accesses menu 72 in a known manner and selects item 90 entitled “Select From Available Networks” as shown in FIG. 15 . Next, handheld electronic device 4 performs a scan to locate the current “available networks.” As seen in FIG. 16 , while this is being done, a dialog box 92 is displayed on display 12 to inform the user that the scan is taking place. Once the scan is completed, “Find” screen 76 as seen in FIG. 17 is displayed on display 12 and includes a listing 94 of all of the “available networks” located during the scanning procedure. The user may then select a particular PLMN for inclusion in the listing 58 and save the listing 58 to the SIM card in the manner described in connection with FIGS. 8 through 14 above. In one embodiment, “available networks” will consist of only “known networks” stored by memory 44 . Alternatively, any network located during the scan may be a “available network.” Again, once the listing 58 is saved to the SIM card, it, and not the pre-stored list provided in the SIM card described above, is used to determine which and in what order PLMNs are to be used by handheld electronic device 4 , if available, in roaming situations.
According to an aspect of the invention, the user may easily reorder, and thus change the priority of, the PLMNs listed in listing 58 by selectively moving their location in listing 58 . Specifically, according to one embodiment, if a user wants to move a PLMN appearing on listing 58 (for example, the “ABA Network”), the user can, as shown in FIG. 18 , identify the PLMN to be moved on “Preferred Network List” screen 56 using the input apparatus in a known manner, access menu 60 therefrom, and select item 96 entitled “Move.” When this is done, the identified PLMN is highlighted as shown in FIG. 19 . The identified and highlighted PLMN may then be moved to another location on the listing 58 using input apparatus 16 , preferably, although not necessarily, by rotating thumbwheel 28 (alternatively, various keys, such as “up” and “down” arrow keys, may be used). Once the identified PLMN is in the desired location on listing 58 , its location may be confirmed using input apparatus 16 , preferably, although not necessarily, by pressing thumbwheel 28 , at which time the moved PLMN will no longer be highlighted. As seen in FIG. 20 , once the PLMN is moved, the PLMNs in listing 58 are automatically reordered and renumbered, meaning their assigned priority is changed, if necessary. If desired, the listing 58 as currently appearing in “Preferred Network List” screen 56 may then be saved to the SIM card (with the new assigned priorities) in the manner described in connection with FIGS. 8 through 14 . In addition to moving PLMNs listed in listing 58 , particular PLMNs may be deleted from listing 58 and/or stored information (the information in fields 66 , 68 , 70 and 84 ) for particular PLMNs may be displayed on display 12 by identifying the particular PLMN as described above and then selecting the appropriate item (“Delete” or “View”) in menu 60 shown in FIG. 18 . When a PLMN is deleted from listing 58 , the remaining PLMNs in listing 58 are automatically reordered and renumbered, meaning their assigned priority is changed, if necessary.
Thus, the invention provides a handheld electronic device that enables a user to selectively establish a prioritized list of preferred PLMNs to be used in roaming situations. In this manner, a user is able to select and prioritize particular PLMNs based on issues of PLMN cost, reliability, and service quality, among others, thereby saving the user money and/or enhancing performance of the handheld electronic device.
While specific embodiments of the invention have been described in detail, it will be appreciated by those skilled in the art that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure. Accordingly, the particular arrangements disclosed are meant to be illustrative only not limiting as to the scope of the invention which is to be given the full breadth of the claims appended and any and all equivalents thereof.
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A handheld electronic device adapted to display a listing of known networks, scan for available networks, display a listing of the available networks and enable the entry of information relating to manually entered networks. In addition, the device is adapted to (1) enable the addition of preferred networks to a preferred network list wherein the preferred networks are one or more of: (i) certain of the known networks selected from the listing of known networks, (ii) certain of the available networks selected from the listing of available networks, and (iii) the manually entered networks; (2) enable the assignment of a priority value to each of the preferred networks; and (3) utilize the preferred networks for performing wireless communications when the device is in a roaming situation, wherein the preferred networks are utilized in a priority order that is based on the priority value assigned to each of the preferred networks.
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BACKGROUND AND SUMMARY OF THE INVENTION
[0001] The present invention relates to a method of and an apparatus for treating green liquor formed in a kraft sulphate or soda pulp mill.
[0002] The kraft or sulfate process produces a high percentage of the chemical pulp produced annually in the world. In the kraft process, wood chips are cooked (digested) at an elevated temperature and pressure in “white liquor”, which is a water solution made up of primarily sodium sulfide (Na 2 S) and sodium hydroxide (NaOH). The white liquor chemically dissolves lignin from the wood. Spent cooking liquor and the pulp wash water are combined to form a weak black liquor which is then concentrated in an evaporator. The concentrated black liquor is fired in a recovery furnace or recovery boiler. Inorganic chemicals present in the black liquor collect as a molten smelt at the bottom of the furnace. The smelt, consisting primarily of sodium carbonate (Na 2 CO 3 ) and sodium sulfide (Na 2 S) is then removed from the recovery furnace/boiler and dissolved in water in the smelt tank to create green liquor.
[0003] An essential part of the process of producing kraft pulp is chemical recovery. The chemical recovery process includes the production of white liquor used in the pulping process. White liquor is produced by a causticizing process, whereby green liquor is reacted with calcium hydroxide, i.e. slaked lime, to regenerate the white liquor through the following equilibrium reaction:
[0000] Na 2 CO 3 +Ca(OH) 2 2NaOH+CaCO 3
[0004] Green liquor also contains insoluble compounds, know as dregs, including some inorganics of all types, flecks of carbon, and unburned organics. Dregs must be removed in the green liquor filter or they continue through the recovery cycle and become a dead load in the system. Clarifying the green liquor to remove dregs improves white liquor clarification, mud settling, mud washing, and soda removal on the lime kiln precoat filter.
[0005] It is known in the art to use a green liquor filter that uses pressure differential across the filter element to drive the separation of dregs solids from green liquor. Ordinarily both the high and low pressures in the filter are above atmospheric pressure, in accordance with the process requirements in the downstream white liquor filter, where pressurized operation always above atmospheric prevents heat loss by flashing of water to vapor and the subsequent loss of heat from the white liquor.
[0006] As indicated, green liquor is reacted with lime in a slaker and is converted to white liquor which is subsequently carried to a digester. The slaker is operated as close to boiling as possible to produce a high grade lime mud slurry. The lime mud slurry can be washed in water in one or several steps before it is dewatered and fed into a lime mud kiln. Calcination of the lime mud takes place in the lime mud kiln, which converts the content of calcium carbonate to lime, which principally consists of calcium oxide (CaO). This lime can subsequently be used in a lime slaker as described above.
[0007] Green liquor exiting the filter is typically hot, normally about 95° C., and at times higher, and if not cooled sufficiently it can cause the slaker to boil over. In prior art processes the hot green liquor solution is typically directed from the filter to a separate cooling device to reduce its temperature. The cooling device can be either a heat exchanger or vacuum flash cooler system. However, because of the chemical content of the green liquor solution, scaling, i.e., the deposition of chemicals in solution as a solid on pipe and vessel walls, can be a significant problem with the shell and tube exchangers. Vacuum flash coolers do not scale as quickly but are an expensive alternate to heat exchangers In addition, while dregs cake washing is increasingly required to meet stricter environmental requirements for dregs discharged from the filter, an undesirable result is that the strength of the green liquor within the filter is sometimes weakened.
[0008] Therefore, one objective of the invention is to have a method of efficiently cooling green liquor before it is fed to the slaker. Another objective is to have a cooling step for green liquor prior to the slaker in which scaling does not occur in the cooling apparatus. A further objective is to concentrate the green liquor back to the optimal strength that existed when it was fed to the green liquor filter prior to the dregs cake washing.
[0009] These objects and other features and advantages of the present invention will be appreciated and understood by those skilled in the art from the following detailed description and drawing.
DESCRIPTION OF THE DRAWING
[0010] The FIGURE is a diagrammatic view of a green liquor treatment system and method of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0011] The present invention provides for a novel approach in which the green liquor filtering step is combined with the green liquor cooling step in a single apparatus.
[0012] Green liquor as produced from the smelt derived from black liquor in chemical recovery of a conventional Kraft liquor cycle is directed to an agitated stabilization tank 11 . The agitation provided turns the contents of tank 11 over fairly quickly but not enough to shear any dregs that are present. The agitated green liquor is thereafter directed to green liquor filter 12 adapted for removing dregs from the green liquor solution. A green liquor filter that can be advantageously utilized in the present invention is FLSmidth Dorr-Oliver Eimco Inc.'s Green Liquor ClariDisc® Filter. Green liquor filter 12 has solution inlet 13 , solution outlet 14 and dregs outlet 15 and one or more internal filtration element (not shown) to filter dregs from the green liquor solution wherein there is a pressure differential across the filtration element, and the filter unit as a whole, from a relatively higher pressure at or adjacent to the filter inlet (i.e. the “upstream” side, relative to the movement of the green liquor solution therethrough) to a relatively lower pressure at or adjacent to the filter outlet (i.e. the “downstream” side). Dregs removed from the green liquor solution then exit through outlet 15 and are typically disposed.
[0013] Because of the low pressure conditions, the flashing off of vapor from the green liquor and the resultant cooling of the green liquor is primarily achieved within green liquor filter unit 12 and starting on the immediate downstream side of the unit's filtration element. As the heat of vaporization for water is approximately 1000 BTU per pound, for every pound of water removed as vapor, approximately 1000 BTUs are removed from the solution and the loss of one BTU will drop the temperature of one pound of water one degree F. Since green liquor is predominantly made up of water, it will cool with the removal of BTUs from the solution.
[0014] The green liquor and vapor are thereafter delivered to a green liquor separator vessel 16 . In separator vessel 16 the vapor is separated from the liquid. Vessel 16 optionally may also be exposed to negative pressure. Since there is no heat exchange surface per se in the separator vessel, scaling is not a problem.
[0015] The removal of water vapor from separator 16 via outlet duct 19 increases the chemical concentration in the Green Liquor. The negative pressure condition that causes the flashing is achieved with a source 17 of differential pressure such as a liquid ring vacuum pump or a compressor. The vapor load created can be huge while the noncondensible load (air and other gases that do not condense) is very small. Therefore, the liberated vapor stream, i.e., the flash vapor and non-condensables that are present in the vapor phase off the separator vessel are sent to condenser 18 where most of the flash vapor is condensed either by direct contact with a cooling water stream or indirectly by a heat exchanger. But in this case, the heat exchanger is fed only vapor which is free of dissolved solids so scaling is not an issue. The method of condensation employed can determine where to direct the discharge from the condenser. For example, if a barometric condenser is employed the discharge is typically directed to weak wash or another process step demanding water. If an indirect condenser is used, then all, none or a portion of the condensate produced can be directed back to mix with the clarified green liquor.
[0016] The concentrated and cooled green liquor is removed from separator 16 via outlet duct 20 . Within condenser 18 the vapor is condensed back into water. As indicated, in one embodiment some or all of this water can be returned to the concentrated green liquor via duct 21 depending upon the desired strength of the green liquor solution to be delivered to the slaker, that is, if the cooled green liquor is stronger than optimum. If, because of dregs cake washing the green liquor has been diluted below its optimum strength than it may be determined that none of the water is to be combined with the concentrated green liquor. As indicated, some or all of the condensed water can also be utilized elsewhere in the system, such as being directed back to the filter unit to effect the dregs cake wash and is thereafter discharged from the filter unit.
[0017] The noncondensibles (that is essentially dry gas), are preferably recirculated back to filter 12 to prevent oxidation of the liquor. Unlike in prior art green liquor filtration processes that use a separate downstream flash cooling device, the non-condensibles need not be vented to atmosphere on a continuous basis.
[0018] The pressure differential across the filtration element (and between the green liquor inlet and outlet of the filtration unit) in the filter can range from about 0.2 to about 1.8 bar, and will preferably range from about 0.5 to about 1.5 bar. Unlike what is done in the prior art, it is important to maintain the low pressure end of the filter at a negative pressure to facilitate subsequent flash cooling of the green liquor solution. By controlling how far below atmospheric the low side of the filter unit is allowed to go, the practitioner can control how much flashing (and subsequent cooling) occurs in the downstream flash cooler. Preferably, the negative pressure utilized on the low pressure side of the filter will range from just below atmospheric down to about −0.7 bar. Normally, the green liquor will be cooled approximately 10° C. by the process of the present invention. Additionally, the cleaned green liquor will be concentrated in this process. This can be a benefit if the liquor is undesirably diluted within the filter due to the requirement of dregs cake washing. By controlling how much of the condensed water is returned to the cleaned green liquor, the practitioner can ensure the final strength of the green liquor leaving the system is optimum.
[0019] It is to be understood that the form of this invention as shown is merely a preferred embodiment. Various changes may be made in the function and arrangement of parts; equivalent means may be substituted for those illustrated and described; and certain features may be used independently from others without departing from the spirit and scope of the invention as defined in the following claims.
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A method of and apparatus for treating a green liquor stream produced in a kraft pulp process to separate green liquor from dregs present in the stream by utilizing a filtration vessel that has a pressure differential between the green liquor inlet and outlet to drive the dregs from the green liquor. In addition, negative pressure is utilized in the filtration vessel to thereby drive water vapor from and consequently cool the filtered green liquor.
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BACKGROUND OF THE INVENTION
[0001] 1. The Field of the Invention
[0002] The present invention relates to the field of Application Specific Integrated Circuit (ASIC) design and tooling. In particular, the present invention relates to systems and methods for reducing the number of base wafer designs and reducing tooling costs associated with design and fabrication of structured and platform ASIC devices.
[0003] 2. Background and Related Art
[0004] Various approaches are used to build custom logic Integrated Circuit (“IC”) devices. Different components, such as, for example, prefabricated Programmable Logic Devices (“PLDs”) (sometimes referred to as Field Programmable Gate Arrays (“FPGAs”)), gate arrays, standard cells (sometimes referred to as cell-based ICs), and hand-crafted custom logic, can be used to implement a custom logic IC device. Each of the different components is associated with a number of design parameters, such as, for example, development cost, unit cost, design cycle time, manufacturing cycle time, flexibility, risk, complexity, performance, and power consumption. Accordingly, selection of a particular component for use in a custom logic IC can be made based on the design parameters of the component.
[0005] FPGA devices are essentially high-volume standard products and are cost effective for low-volume or low-complexity devices. On the other hand, cell-based and hand-crafted custom ICs may be more appropriate for high-volume high-complexity devices. In between, gate-array devices have typically been used to implement medium-complexity, medium-volume devices.
[0006] However, gate arrays often lack the flexibility to support more complex functionality such as, for example, large amounts of memory, timing generator functions and other specialized functions (e.g., processors and I/O physical interfaces). Thus, cell-based and hand-crafted custom ICs are used to implement this more complex functionality. Unfortunately, with advances in process technology, the resulting development cost of cell-based and hand-crafted custom IC's is rising exponentially, due at least in part to the cost of photolithographic reticle tooling. This increased development cost essentially limits the use of cell-based and hand-crafted custom IC's to very high-volume cost-sensitive applications. That is, it may be difficult to implement high-complexity low-volume applications in a cost efficient manner.
[0007] More recently, a new class of devices, often referred to as Structured ASICs, has emerged to fill the gap between the FPGA and cell-based approaches. Structured ASICs utilize pre-fabricated base wafers which include resources for logic, memory, timing generators and may include other specialized functional blocks, commonly referred to as Intellectual Property (IP). The base wafers are then personalized with a reduced number of customized metal and/or via interconnection levels to produce the desired custom logic device. Structured ASICs share similarity with gate arrays in that both use a base wafer approach. Like gate arrays, each Structured ASIC family requires a set of bases (e.g., from 6 to 12), covering a range of silicon die sizes to address the needs of different size devices and corresponding packages.
[0008] However, structured ASICs differ from gate arrays by including more embedded functions and by pre-designing or fixing more interconnection layers. By minimizing the number of customized interconnection levels required, the tooling development costs can be reduced significantly. Other recent tooling mechanisms use more advanced process technology (i.e., more expensive tooling) for base wafers and less advanced process technology (i.e., less expensive tooling) for the customized levels. These more recent mechanisms distribute the development cost of the base wafer across multiple custom logic devices to reduce overall development cost. Along with relatively lower development cost for a small number of less expensive customized interconnect level tooling, the total tooling cost for a device may be substantially reduced.
[0009] One challenge in selecting the architecture of structured ASIC devices is deciding what type of and in what quantity pre-designed functional blocks should be embedded in the base. If the appropriate IP functions are not included, the corresponding device will not be usable for certain applications. If too many embedded IP functions are unused in a particular application, significant silicon area will be unused, potentially making the cost of the device too high.
[0010] One solution is to build a special type of structured ASIC called a platform ASIC that addresses the needs of a particular set of applications. For example, a communications platform ASIC might include I/O processing cores and I/O physical interfaces, whereas a signal processing platform ASIC might include Digital Signal Processing (DSP) processing components and A/D and D/A converters. However, developing multiple platforms each requiring a number of bases (e.g., 6 to 12) requires a significant financial investment.
[0011] Further, there are other tooling costs in addition to the photolithographic reticles discussed above. These costs include reticles for flip-chip style pad ReDistribution Layers (“RDLs”), wafer probe cards, and customized IC package development. Each base in a Structured (or Platform) ASIC family will require these additional types of tooling, and thus, will incur some additional corresponding cost, which can usually be distributed across multiple custom logic devices.
[0012] Prior art contains various approaches to reducing the number of base wafers required to implement a gate array family. One approach uses a borderless gate array to print a sea of transistors across the surface of the die. The actual die border is defined by scribe lines in the programmable levels. In this manner a one-size-fits-all base is created from which different size die can be created.
[0013] However, the borderless approach faces several problems. One problem is finding an effective way to achieve isolation from the scribe line region. Scribe lines defined in the programmable levels may provide good definition of the cutting region but since scribe lines typically do not extend into base layers, good isolation is difficult to achieve.
[0014] A second problem arises due to the intrinsic differences between transistors designed for use in core logic functions and those intended for use in I/O functions. Typically the I/O transistors are much larger, operate with different voltages and require special ESD protection structures. With the borderless approach it is desirable to be able to use any part of the base for core logic functions and any part for I/O functions. Various approaches have been used to achieve dual-use transistors, but the disparity in core and I/O transistor requirements continues to widen, making it evermore difficult to create efficient dual-use structures.
[0015] Most borderless approaches do not handle alignment marks and other photolithograhic and processing artifacts very efficiently, often resulting in significant wasted silicon real estate. Accordingly, it may be difficult to align repeating patterns on the base with repeating patterns on programmable levels. Many existing mechanisms avoid this alignment issue by intentionally wasting space. As such they are typically directed to prototyping and are typically not useful for volume production.
[0016] Prior art also includes the concept of a base wafer with borders in one-dimension. These borders effectively create strips of core cell logic functions and I/O functions. The strip dimensions are fixed in one direction, but as wide as the wafer in the other direction, permitting a range of rectangular sized die to be created by defining scribe lines in the programmable levels.
[0017] To some extent, the one-dimensional bordered arrays solve the problem of sharing core logic and I/O functions. However, one-dimensional bordered arrays require that I/O functions are restricted to running along the two side borders. Thus, problems with isolation in the scribe line regions in the unbordered direction and problems with repeating patterns of alignment and other manufacturing artifacts still exist.
[0018] Additionally, prior art includes base wafers with borders in two-dimensions. The resulting rectangular regions may be clustered or stitched together to form a larger die. However, these two-dimensional bordered arrays have been limited to the traditional sea-of-transistor architecture. They use traditional I/O ring architectures and route I/O from the interior portions of the I/O rings to wire-bond pads around the periphery of the final die. Some two-dimensional bordered arrays include circuitry in the scribe line regions specifically for bridging signals from one region to another.
[0019] The two-dimensional bordered arrays solve some of the scribe line, core logic and I/O function problems. However, problems related to isolating circuitry in the scribe line regions and dealing with the multitude of alignment, manufacturing and testing artifacts placed on a wafer surrounding the individual die still exist. These problems are particularly acute when the base die reticle fields have a different repeat sequence than the programmable level reticle fields. Accordingly, what would be advantageous are systems and methods for reducing the number of bases and reducing base tooling expenses associated with structured and platform ASICs while optimizing die size for individual applications.
BRIEF SUMMARY OF THE INVENTION
[0020] The principles of the present invention are directed towards reducing the number of base wafer designs and reducing tooling costs associated with design and fabrication of Application Specific Integrated Circuit (ASIC) devices. One embodiment provides for a master or universal base and base tooling which addresses the general purpose Structured ASIC requirements. Another embodiment provides for a common set of base tooling from which the master/universal base is created as well as additional custom bases with customized selection and quantity of embedded Platform ASIC functions. Embodiments can utilize conventional Structured ASIC architecture and processing and are compatible with traditional wafer probing and packaging methods and technologies.
[0021] Additional features and advantages of the invention will be set forth in the description that follows, and in part will be obvious from the description, or may be learned by the practice of the invention. The features and advantages of the invention may be realized and obtained by means of the instruments and combinations particularly pointed out in the appended claims. These and other features of the present invention will become more fully apparent from the following description and appended claims, or may be learned by the practice of the invention as set forth hereinafter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] In order to describe the manner in which the above-recited and other advantages and features of the invention can be obtained, a more particular description of the invention briefly described above will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. Understanding that these drawings depict only typical embodiments of the invention and are not therefore to be considered to be limiting of its scope, the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings in which:
[0023] FIG. 1A illustrates a universal integrated circuit base wafer with individual base die.
[0024] FIG. 1B illustrates the universal integrated circuit base wafer of FIG. 1A with individual base die grouped into corresponding customized die clusters.
[0025] FIG. 1C illustrates a more detailed view of an example die cluster region
[0026] FIG. 1D illustrates a more detailed view of an individual base die region.
[0027] FIG. 1E illustrates a more detailed view of a scribe line region between four individual base dies.
[0028] FIG. 1F illustrates customized die clusters formed from grouping corresponding pluralities of individual base die together.
[0029] FIG. 1G illustrates the section view of the customized die clusters of FIG. 1F .
[0030] FIG. 2A illustrates a reticle field filled with a repeating pattern of base die.
[0031] FIG. 2B illustrates a reticle field filled with the outline of a die cluster pattern.
[0032] FIG. 3 illustrates an example flowchart of a method for designing and fabricating universal base wafers.
[0033] FIG. 4A illustrates a customized base wafer with different types of individual base die.
[0034] FIG. 4B illustrates the customized base wafer of FIG. 4A with different types of individual base die grouped into corresponding customized die clusters.
[0035] FIG. 4C illustrates a customized die cluster region formed from grouping different types of individual base die.
[0036] FIG. 4D illustrates an individual base die region.
[0037] FIG. 5A illustrates a reticle field containing multiple different die patterns and blade space.
[0038] FIG. 5B illustrates a reticle field containing multiple different die patterns, special scribe-line patterns and blade space.
[0039] FIG. 6 illustrates an example flowchart of a method for designing and fabricating universal multi-pattern base reticles.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0040] The principles of the present invention are directed towards reducing the number of base wafer designs and reducing base tooling expenses associated with structured and platform ASICs while optimizing die size for individual applications.
[0041] Generally, silicon wafers used in the fabrication of integrated circuits can be partially fabricated up through a desired processing level (e.g., to implement partial IC functionality). The wafer at this stage is commonly referred to as a “base wafer”. To accomplish this, one or more levels are created through a conventional photolithographic process involving a series of printing and processing steps. For each level, a pattern is printed on a reticle with appropriate alignment marks for aligning of the reticle to the previous levels on the base wafer. The pattern of the reticle is applied to the surface of the base wafer to print a pattern on a portion of the wafer. Then, the reticle is stepped to other locations on the wafer using the alignment marks to print the pattern on a different wafer location. The use of alignment marks facilitates alignment between different levels and across different regions of the base wafer. Printing, movement, and alignment can continue until an appropriate repeating pattern results. Base wafers can be stored for further processing at a later time.
[0042] FIG. 1A illustrates an integrated circuit (“IC”) base wafer 100 with individual base die. Base wafer 100 can be fabricated using a set of reticles, each having a pattern and appropriate alignment marks. As depicted in FIG. 1A , base wafer 100 includes a plurality of repeating individual die (represented by the space within the lines). Base level scribe lines surround each of the individual die in base wafer 100 (indicating where individual die to are to be cut).
[0043] Subsequently, the stored base wafers can be retrieved and further processed (e.g., to implement customized IC functionality). Unlike conventional IC fabrication, this invention allows processing which can include utilizing a grouping pattern on a customized reticle to group individual die into die clusters.
[0044] FIG. 1B illustrates the IC base wafer 100 with individual base die grouped into corresponding customized die clusters (represented by the space within thicker lines). Customized die clusters can be printed on top of individual die using a conventional IC photolithographic processing approach with customized reticles. Each of the customized die clusters can include one or more individual die. FIG. 1B depicts groupings of four-by-four individual die (16 individual die total) within each customized die cluster. However, the customization process can be utilized to create a wide variety of different individual die grouping configurations (e.g., 1×6, 2×3, etc.). It may be even that a customized die cluster includes a single individual die.
[0045] FIG. 1C illustrates a more detailed view of an example die cluster region 103 . Although the die cluster region 103 centers on a particular die cluster, portions of surrounding die clusters are also shown for context. Similarly, although the individual base die region 102 centers on an individual base die, surrounding individual base dies are also shown within the region for context. The size of an individual die cluster can vary across a range of appropriate sizes. However, in FIG. 1B the distances 180 and 181 can be some number of millimeters, such as, for example, in a range from 4 to 10 mm. Scribe line intersection region 104 includes an intersection of scribe lines included in base wafer 100 .
[0046] The regular and repeating structure of base wafer 100 is thus customized by printing an appropriate interconnection pattern for each customized die cluster on the final layers. The resulting interconnection pattern of die cluster 103 interconnects various components of base wafer 100 to one another. Interconnections between individual base die as well as within individual base die can be facilitated with upper level interconnects. Scribe lines on the customized levels surround each of the custom die clusters (indicating where custom die clusters are to be cut) and thereby define the final die size.
[0047] Since customized die cluster patterns 103 are printed on top of individual die patterns (e.g., of base wafer 100 ), not all scribe lines between individual die will be completed during the fabrication process. That is, based on the customized die cluster configuration, only some of the base level scribe lines will be co-incident with custom level scribe lines. Co-incident base level scribe lines are extended up into the customized levels resulting in a completed scribe line. A customized die cluster can be cut from the wafer using this completed scribe line.
[0048] However, other base level scribe lines (e.g., base level scribe lines not on a boundary between customized die clusters) will be internal to a customized die cluster. That is, the customized die cluster interconnections between the individual die essentially cover over these internal base level scribe lines. Accordingly, these internal base level scribe lines are left incomplete and are not used during the wafer fabrication process. Since these covered internal base level scribe lines remain intact during fabrication, functional resources embedded in the covered internal base level scribe lines can also be interconnected to and used by the rest of circuitry forming a customized die cluster.
[0049] FIG. 1D illustrates a more detailed view of an individual base die region 102 . As depicted, an individual base die (as bounded by scribe line regions 109 ) can include, but is not limited to, logic gates 105 , memory 106 , I/O resource 107 , and flip-chip solder bump sites or bond pads 108 . Scribe line regions 109 surround these other components of the individual base die. Scribe line regions 109 are essentially isolation regions designed to surround the active silicon device area and protect the device from the destructive effects of scribing and cutting of a wafer into individual die.
[0050] In some embodiments, I/O resources are distributed around the periphery of an individual base die and can include bond pads for bond wire connections to the package. In other embodiments, a flip-chip redistribution layer (“RDL”) is utilized to spread out I/O cell connections to flip-chip solder bumps. Thus, in these other embodiments, I/O cells may be grouped together in large rectangular regions, allowing electro-static discharge (“ESD”) energy to dissipate and allowing creation of I/O cells with efficient aspect ratios.
[0051] The size of an individual base die cluster can vary across a range of appropriate sizes. However, in FIG. 1D , distances 182 and 183 can be some number of millimeters and are smaller than or equal to distance 180 . For example, referring back to FIG. 1C , a four-by-four array of individual die are included in each customized die cluster.
[0052] FIG. 1E illustrates a more detailed view of a scribe line intersection region 104 . Scribe line intersection region 104 depicts scribe line regions 109 that separate four individual base dies. Some of the components of the individual base dies, such as, for example, I/O module 107 and flip-chip solder bump sites or bond pads 108 of the upper left individual base die, are also depicted. Furthermore, there are also other components even within the scribe line regions 109 . Such other components include, for example, guard rings 110 , alignment marks 111 , process monitor devices 112 , scribe-line monitor devices 113 , and embedded circuit or function region 114 . Alignment marks 111 , process monitor devices 112 , and scribe-line monitor devices 113 can be used during the wafer fabrication process. Process monitor devices 112 and scribe-line monitor devices 113 can be probed and examined before they are destroyed during the scribing process. During printing, alignment marks 111 can be utilized to align a reticle for a die cluster with alignment marks on previous layers, such as, for example, associated with the individual die of base wafer 100 .
[0053] Guard rings 110 isolate active silicon regions (i.e., the portions that would remain after scribing) from inactive silicon regions (i.e., the portions separated by scribing). Scribing may then occur along finished (or completed) scribe lines as defined by the clusters. This provides significant flexibility in the configuration of the resulting die. Furthermore, the scribe lines that are not cut during die separation (e.g., covered internal base level scribe lines) may themselves contain useful circuitry. For example, if a vertical scribe line is cut and an intersecting horizontal scribe line remains uncut, circuitry in the horizontal scribe line area remains protected and useable.
[0054] The guard ring locations can be pre-designated in a repeating interconnect pattern along all scribe lines that are potentially subject to scribing. Guard rings can extend into the scribe line area such that corresponding portions of circuitry (in a partially completed scribe line) are protected and can remain intact after a cut along a perpendicular adjacent (or intersecting) finished (or completed) scribe line.
[0055] FIG. 1F illustrates customized die clusters formed from grouping corresponding pluralities of individual base die together. More specifically, portion 115 represents a portion of the surface of a customized IC wafer. Portion 115 depicts two customized die clusters 122 each including four individual die (in a two-by-two configuration). Finished scribe lines 116 (represented by the solid lines following the mid-line of the scribe lines) at the boundaries of each customized die cluster 122 indicate locations where portion 115 is to be cut. Alignment marks 111 , process monitor devices 112 , and scribe-line monitor devices 113 are also depicted.
[0056] Scribe line regions internal to a cluster (e.g., scribe line regions 109 ) represent unused silicon area. Through appropriate isolation, each scribe line region can include a region where resources can be embedded. For example, embedded region 114 depicts a region where resources can be embedded in scribe line region 109 . Any number of different resources can be embedded in embedded region 114 , such as, for example, logic fabric (e.g., sea of gates or sea of macros), I/O blocks (e.g., I/O cells, bond pads, flip-chip solder bumps, or ESD protection), memory, timing generators (e.g., delay locked loops or phase locked loops), I/O physical interfaces (e.g., dual-data-rate PHYs, or high-speed serial/de-serializers), and processors. Thus, at least some of the space consumed by scribe line regions can be reclaimed and used to implement the desired functionality of an IC device.
[0057] FIG. 1G illustrates a section view of the customized die clusters of FIG. 1F . Interconnects on the upper customizable levels 117 personalizes the design by connecting with the predefined interconnect 118 and active devices 119 in base wafer portion 115 . Interconnect on the upper customized levels 117 can span the partially formed base isolation regions 120 (covered base level scribe lines) as necessary to complete connections in and between the regions. The customized 117 can thereby be used to define the size of the final die cluster depending on how many individual die are used and in what configuration.
[0058] The customized levels also place scribe lines 116 around each of the (two-by-two) customized die clusters 122 . These scribe lines complete those base level scribe lines (e.g., in region 123 ) which correspond to the size of the final customized die cluster. Any number of predefined interconnect levels 118 and customizable levels 117 may be used. The customizable interconnect levels 117 may include any mix of predefined and customizable metal and via levels in any configuration.
[0059] Embodiments of the present invention can facilitate creation of a universal base wafer. Any number of reticle tooling levels can be utilized to create a universal base wafer. Reticle tooling can be used as part of a photolithographic process to imprint a reticle field on a wafer. The photolithographic process can be optimized by placing multiple die images in the reticle field, which are then stepped and repeated or scanned across the wafer, exposing a photoresist. Other examples of photolithographic processes that can be used to create a base wafer include: full field, stepper, scanner, laser, and e-beam. When complete, the surface of the wafer contains a uniform array of individual base die.
[0060] FIG. 2A illustrates an example reticle field 224 that includes reticle tooling 223 for one level of a universal base wafer. Reticle tooling 223 is configured in a six-by-six configuration 225 of individual die images (e.g., each representing an area bounded by thin lines in FIGS. 1A and 1B ). Reticle field 224 can be can be repeatedly moved and printed on a wafer as previously described. For example, multiple imprints of reticle tooling 223 can be used to create the pattern of base wafer 100 . Scribe line regions of a reticle field can be designed separately from the base die themselves and create a pattern which repeats every field dimension, as opposed to every die dimension (freeing up space to place circuitry and functions in scribe line regions that are to be covered over). The scribe line regions are designed such that any special embedded resources 114 are repeated on the die dimension.
[0061] A wide variety of reticle tooling configurations can be used to create the pattern of base wafer 100 . For example, it may be that reticle tooling configured as a six-by-six or even three-by-five configuration of individual die images is used to create the pattern of base wafer 100 . Increasing the number of individual die images in reticle tooling 223 reduces the number of times reticle field 224 must be imprinted to create the pattern of base wafer 100 . Thus, it may that reticle field 224 is filled with as many die images 225 as possible to correspondingly reduce the number of wafer printing steps to as few as possible
[0062] FIG. 2B illustrates a reticle field 227 that includes reticle tooling 226 representing the outline of a die cluster pattern. Reticle tooling 226 defines a custom die cluster configuration that is to group four-by-four individual die when printed on a base wafer. For example, reticle tooling 226 can be printed on base wafer 100 to create the areas bounded by the thicker lines in FIG. 1B . The vertical dashed lines 228 and horizontal dashed lines 229 represent underlying individual die boundaries (e.g., scribe line regions that result from printing reticle tooling 223 ) that are to be covered over (and thus become internal to a custom die cluster) when reticle field 227 is printed on a wafer (e.g., as depicted in FIG. 1G ).
[0063] Reticle field 227 can include tooling for completing embedded artifacts in base level scribe line regions that are to be covered (i.e., internal base level scribe line regions). Since base reticle fields and customized cluster reticle fields may be of different configurations (in arrangement and/or number of individual die), scribe line artifacts can be organized in repeating patterns such that no interference is created between artifacts in these fields. For example, artifacts can be placed on a regular repeating grid based on pre-defined internal base level scribe line regions. For example, artifacts can be placed in internal base level scribe line regions corresponding to the locations of vertical dashed lines 228 and horizontal dashed lines 229 (i.e., the covered die boundaries). Artifacts can be placed in patterns which permit any repeat frequency of cluster configuration patterns (e.g., the pattern represented in reticle field 226 ) to overlay the base pattern (e.g., the pattern of base wafer 100 ).
[0064] A number of different types of artifacts, such as, for example, artifacts required only in the base, artifacts required only in the customizable levels, and artifacts which are composed of features in the base and customizable levels, can be utilized.
[0065] Scribe line artifacts which are only required in the base levels can be repeated with a frequency determined by the dimensions of the base reticle field pattern 223 . Where these artifacts become part of internal base level scribe lines (e.g. they are covered by customizable levels 228 , 229 ) they can be covered with interconnect. They may optionally be made accessible by cut-outs in the customizable levels. These cut outs can be repeated at all possible beat frequencies of the base reticle field pattern 223 and the customizable field pattern 226 .
[0066] Scribe line artifacts which are only required in the customizable levels need not have any special provision in the base levels.
[0067] Artifacts which originate in the base level scribe line regions and require additional features in the customizable levels to form complete structures can be repeated at all possible beat frequencies of the base reticle field pattern 223 and the customizable field pattern 226 .
[0068] FIG. 3 illustrates an example flowchart of a method 300 for designing and fabricating universal base wafers. The method 300 will be described with some reference to the elements in FIGS. 1A-1G and 2 A and 2 B. The method 300 includes an act of designing a base die (act 301 ). Act 301 can occur before any particular customized integrated circuit is planned. A designer can use an appropriate software application to configure various blocks of the base die from cell libraries. A base die can be designed according to conventional ASIC die architecture with I/O cells distributed around the periphery of the base die and with logic and other embedded functions in the core of the base die. Alternately, a base die can be designed according to a modular die architecture with I/O cells, logic and other embedded functions included in blocks and/or I/O cell clusters for ESD dissipation. A base die can be designed such that the used portions of scribe line regions (e.g., corresponding to base level scribe lines potentially covered during customization) can be filled with embedded resources, such as, for example, timing generators and logic fabric.
[0069] The method 300 includes an act of creating a set of one or more base die reticles for the base die (act 302 ). Act 302 can include assembling a set of reticles for a corresponding base based on one or more of the field size, process monitor and scribe line monitor requirements, and any special embedded resources (e.g., to be embedded in embedded region 114 ). For example, base die reticle with reticle field 224 can be created. Scribe line artifacts (alignment marks, process monitor devices, and scribe line monitor devices) can be organized in a reticle field to avoid interference with customized reticle fields. Scribe lines can be back-filled with embedded functions, such as, for example, timing generators and logic fabric.
[0070] The method 300 includes an act of fabricating base wafers (act 303 ) and an act of storing the base wafers (act 304 ). At any time, for example, determined by fabrication lead times, base wafers are fabricated and subsequently held in inventory (e.g., in a stockroom). Fabrication of a base wafer can include repeatedly printing a base reticle field (e.g., reticle field 224 ) on a wafer. This process can be repeated with each reticle in the base reticle set to build up the base wafer with the desired number of levels. A single type of base wafer (e.g. base wafer 100 ) can be fabricated and held in inventory. This single type of base wafer (a universal base) can then be used for any mix of customized die cluster configurations.
[0071] The method 300 includes an act of designing a custom application (act 306 ) and an act of defining an appropriate die cluster configuration (act 307 ). A die cluster configuration can be defined to meet the resource requirements of the custom application. A die cluster configuration can be defined to include any number of individual die and can be any of a variety of different arrangements (including square, for example, six-by-six and rectangular, for example, four-by-three). Based on the dimensions of individual die (e.g., 1 mm, 2 mm, etc.), the dimensions of the corresponding die cluster can be determined (e.g., 8 mm, 10 mm, etc.) such that cluster boundaries fall on individual die boundaries. A designer can utilize an appropriate software application to configure a cluster from die libraries.
[0072] In some embodiments, one of a set of standardized configurations is defined so as to simplify flip-chip RDL, wafer probing and packaging. In other embodiments, each die cluster configuration is fully customized (e.g., having a different arrangement and/or different number of individual die). In some embodiments, all clusters across a given base wafer are the same. However, in other embodiments, it is possible to mix different sized clusters on a given base wafer.
[0073] The method 300 includes an act of laying out the custom application (act 308 ). For example, after the die cluster configuration is defined, the custom application can be laid out to the die cluster configuration. The method 300 includes an act of creating custom reticles for the custom application (act 309 ). For example, die cluster reticle with reticle field 227 can be created. Depending on the size of a reticle field and the size of different die clusters, the reticle field of a custom reticle can include one or more (potentially different) die clusters. The method 300 includes an act of accessing base wafers (act 311 ). For example, it may be that previously fabricated base wafers 100 are pulled from a stockroom.
[0074] The method 300 includes an act of fabricating custom levels based on the custom reticle (act 312 ). For example, reticle field 227 can be repeatedly printed on base wafer 100 to create a customized base wafer. It may be that a base reticle field configuration is similar to a die cluster reticle field configuration. For example, a base reticle field may be a five-by-five configuration of individual die and a die cluster reticle field may be defined to cover a five-by-five configuration of individual die. However, it may also be that a base reticle field configuration differs from a die cluster reticle field configuration. For example, reticle field 224 is a six-by-six configuration of individual die, while reticle field 227 defines a die cluster to cover a four-by-four configuration of individual die. Accordingly, act 312 can include utilizing a photolithographic process capable of maintaining alignment between the base level and other customizable levels with similar or different repeat sequences.
[0075] When appropriate, a reticle field with one or more (potentially different) die clusters can be utilized to customize a base wafer. For example, such a reticle field can be repeatedly printed on base wafer 100 to create multiple clusters.
[0076] The method 300 includes an act of scribing a custom die cluster (act 313 ). Individual die clusters are tested with wafer probe test equipment, with good dies scribed and cut from the customized base wafer. For example, good die clusters can be cut from base wafer 100 by cutting along the thicker lines depicted in FIG. 1B .
[0077] Other examples of photolithographic processes that can be used to customize a wafer include: laser and e-beam techniques. Laser and e-beam techniques use a raster scan technique to print stripes many individual/cluster die per pass. When many stripes are printed, a full row of die, such as, for example, in FIG. 1B , can be created.
[0078] FIG. 4A illustrates a customized base wafer 400 with different types of individual base die. As depicted, customized base wafer 400 includes different individual base die regions 401 and 402 . Customized base wafer 400 can be created from a universal base reticle set having multiple different individual die patterns. The multiple different individual die patterns can be selectively printed to a base to create customized base wafer 400 . Different die patterns can be of similar (or even the same) dimensions. Utilizing alternate die patterns with the same dimensions makes it possible to interchange the alternate die patterns (on the base), while having little, if any, impact on the ability to cluster and scribe arbitrary numbers of base die for larger customized die. FIG. 4B illustrates the customized base wafer of FIG. 4A with different types of individual base die grouped into corresponding customized die clusters.
[0079] The different base die patterns can contain various pre-defined embedded function blocks, such as, for example, included in alternate individual base die region 401 . FIG. 4C illustrates a customized circuit die cluster region 403 formed from different types of individual base die, such as, for example, individual die included in individual base die regions 401 and 402 . FIG. 4C illustrates how the customized levels would then interconnect these customized circuit die cluster regions 403 as described previously. Interconnection of customized levels facilitates creation of platform ASIC type devices of different sizes and compositions from a single reticle set, potentially significantly reducing NRE cost. The size of an individual die cluster can vary across a range of appropriate sizes. However, in FIG. 4C the distances 480 and 481 can be some number of millimeters, such as, for example, 8 mm. Thus, in FIG. 4D , it may be that distances 482 and 483 , for 0<example, represent a 2 mm by 2 mm die size.
[0080] FIG. 4D illustrates an individual based die region 401 . Individual base die 401 is an example composition of an alternative die pattern (from individual base die region 402 ) which contains a high-speed SerDes I/O block 404 and logic gates 406 . Any number of different die patterns containing a variety of different embedded functions is possible. The number of different die patterns can be based on the standardized base die size and the number of alternative die patterns that fit in the reticle field. Alignment marks 411 can be used during the wafer fabrication process.
[0081] FIG. 5A illustrates a reticle field 540 containing multiple different die patterns and blade space. One of these die patterns can be used to print a first type of individual die, while another one of these patterns can be used to print a second type of individual die. For example, pattern 532 can correspond to individual die in individual base die regions 402 and pattern 537 can correspond to individual base die in individual base die regions 401 .
[0082] Within reticle field 540 , four different base die patterns are depicted, including a standard die pattern 532 , a SerDes die pattern 537 , a die pattern 541 that contains larger memory blocks, and a die pattern 542 that contains dedicated high-speed I/O PHYs. Various mechanisms can be used to selectively expose just a portion of reticle field 540 on a base wafer. These mechanisms can include blading or masking out appropriate (and/or non-desirable) die. Blading or masking out can require extra space 543 between the different die patterns in reticle field 540 . Blading or masking techniques can include full field, stepper and scanner.
[0083] FIG. 5B illustrates a reticle field 544 containing multiple different die patterns, special scribe-line patterns, and blade space. Depicted in reticle field 544 is large scribe line frame 545 and masked regions 546 . The large scribe line frame 545 can be exposed first and then individual die 532 , 537 , 541 , and 542 can be exposed over the masked regions 546 in the desired pattern. Accordingly, a number of alternating die patterns can be used in a manner that has little, if any, adverse effect on requirements of process monitors, scribe line monitors, and embedded functions (e.g., embedded in embedded region 114 ).
[0084] FIG. 6 illustrates an example flowchart of a method 600 for designing and fabricating universal multi-pattern base reticles. The method 600 will be described with some reference to the elements in FIGS. 4A-4D , 5 A, and 5 B. The method 600 includes an act of designing a multiple base die (act 601 ). For example, before any particular customized integrated circuit is planned, a universal base reticle (e.g., based on reticle field 540 or 544 ) can be designed. Design of a multiple base die can include using a software program to configure various blocks of each base die from cell libraries.
[0085] The method 600 includes an act of creating a set of multi-patterned base reticles (act 602 ). For example, a photolithographic process can include printing a number of different die patterns on the same reticle to create a multi-patterned reticle. Multi-patterned reticles can be created based on a die size, process monitor and scribe line monitor requirements, and any special embedded resources.
[0086] The method 600 includes an act of designing a custom application (act 603 ) and an act of defining an appropriate die cluster configuration (act 604 ). A die cluster configuration can be defined to meet the resource requirements of the custom application. A die cluster configuration can be defined to include any number of different individual die and can be any of a variety of different arrangements (including square, for example, six-by-six and rectangular, for example, four-by-three). Based on the dimensions of individual die (e.g., 1 mm, 2 mm, etc.), the dimensions of the corresponding die cluster can be determined (e.g., 8 mm, 10 mm, etc.). A designer can utilize an appropriate software application to configure a cluster from die libraries.
[0087] The method 600 includes an act of fabricating custom base wafers (act 606 ) and an act of storing the custom base wafers (act 607 ). At any time, for example, determined by fabrication lead times, custom base wafers are manufactured and subsequently held in inventory (e.g., in a stockroom). Custom base wafers can be fabricated from the multi-patterned recticle, with stepping (or scanning) and blading (or masking sequence) specified by the custom die cluster configuration. For example, during a stepping process, the desired pattern can be selected and exposed. Thus, if there are two die patterns, A and B, on a multi-patterned reticle, rows of individual die can be exposed with the various patterns such as, AAAA, BBBB, ABAB, AAAB, etc. as appropriate.
[0088] The method 600 includes an act of laying out the custom application (act 608 ). For example, after the die cluster configuration is defined, the custom application can be laid out to the die cluster configuration. The method 600 includes an act of creating custom reticles for the custom application (act 609 ). For example, act 609 is similar to act 309 that can be used to create reticle field 227 . Depending on the size of a reticle field and the size of different die clusters, reticle fields of custom reticles can include one or more (potentially different) die clusters.
[0089] The method 600 includes an act of accessing custom base wafers (act 611 ). For example, it may be that previously fabricated custom base wafers are pulled from a stockroom. The method 600 includes an act of fabricating custom levels based on the custom reticles (act 612 ). When appropriate, a reticle field with one or more (potentially different) die clusters can be utilized to customize a base wafer. For example, such a reticle field can be repeatedly printed on customized base wafer 400 to create multiple clusters. The method 600 includes an act of scribing a die cluster (act 613 ). For example, individual die clusters are tested with wafer probe test equipment, with good dies scribed and cut from the customized base wafer.
[0090] Other photolithographic processes such as, for example, laser and e-beam techniques can be used to customize a wafer that has different individual die. When many stripes are printed, a full row of die, such as, for example, as in FIG. 4B , are created.
[0091] Embodiments of the present invention reduce the tooling NRE required to build a master/universal base for structured ASIC and platform ASIC devices. Embodiments of the present invention can utilize conventional architectures to promote compatibility with conventional design and processing tools and flows. Embodiments of the present invention (possibly significantly) reduce the tooling NRE required to build customized bases for platform ASIC devices, for example, by using a single set of reticles.
[0092] The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes, which come within the meaning and range of equivalency of the claims, are to be embraced within their scope.
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One embodiment of the present invention provides for a master or universal base and base tooling which addresses the general purpose Structured ASIC requirements. Another embodiment of the present invention provides for a common set of base tooling from which the master/universal base is created as well as additional custom bases with customized selection and quantity of embedded Platform ASIC functions. Embodiments can utilize conventional Structured ASIC architecture and processing and are compatible with traditional probing and packaging.
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TECHNICAL FIELD
The present invention relates generally to laser staking and welding. More particularly, the invention relates to discontinuing the application of laser radiation to a thermoplastic projection when the projection collapses to a predetermined displacement with respect to a reference position.
BACKGROUND ART
In many industries it is necessary to deform and shape a thermoplastic projection of a workpiece as a part of a fastening or staking process. For example, in the automotive industry it is common for an emblem to be staked to the center of a steering wheel closeout. While earlier approaches to performing such staking activities involved the use of ultrasonics and hot air, ultrasonics typically produce part marking and hot air often results in damage due to over spray of the hot air.
As a result of the above limitations associated with ultrasonics and hot air, laser staking has evolved in many industries. In conventional laser staking approaches, a projection of a workpiece is deformed by applying a predetermined level of laser radiation and a predetermined weld force to the projection with a specialized dye. The predetermined weld force and the predetermined level of laser radiation cause the projection to melt and collapse into the shape of the dye. After a predetermined period of time, the laser radiation and weld force are discontinued, and the projection is allowed to solidify. After solidification, the staking process is complete and the workpiece is fixed to the adjacent part.
A particular area of potential improvement for the above laser staking process relates to what parameter is monitored to determine when to discontinue the laser radiation and weld force. Specifically, the above discussed weld time control strategies fail to take into account molding and environmental history variables for the parts being staked together. For example, various projections will exhibit varying amounts of collapse for a given weld force, laser radiation and staking time. The final assemblies would therefore have varying overall physical dimensions due to collapse inconsistencies. The present invention recognizes that the collapse distance of the projection is the parameter of most interest and in large part determines the strength and quality of the part connection. It is therefore highly desirable to provide a mechanism for controlling the laser staking process which takes into consideration the staking parameter of most interest, i.e., collapse distance. Such a mechanism would provide reduced rework costs and improved quality.
The difficulties relating to determining what parameter to monitor in order to determine when to discontinue the laser radiation and weld force are equally applicable in other areas of laser welding. For example, in through transmission infrared (TTIr) welding, a first part that is transparent to the laser radiation is welded to a second part that absorbs the radiation. The laser radiation raises the temperature of the absorbent material to a critical melting temperature and the pressure is applied to press the parts together. A weld or bond joins the parts as the melt cools. TTIr welding has widespread application due to its relatively rapid formation of the weld as well as the strength and uniformity of the joint. Thus, in TTIr welding the collapsed distance within the weld zone can be most representative of the strength and quality of the part connection. It is therefore also highly desirable to provide a mechanism for controlling TTIr welding which takes into consideration the welding parameter of most interest, i.e., the collapsed distance.
SUMMARY OF THE INVENTION
The above and other objectives are provided by a system and method in accordance with the present invention for deforming a projection of or creating a weld within a workpiece to join an assembly of parts. The method includes the steps of applying a predetermined weld force to the assembly, and applying a predetermined level of laser radiation to the assembly. The predetermined weld force and the predetermined level of laser radiation cause the assembly to collapse. The method further provides for discontinuing application of the laser radiation when the assembly collapses to a predetermined displacement with respect to a reference position. In one embodiment of the present invention, application of the weld force is discontinued upon expiration of a predetermined time period after the radiation is discontinued to allow for solidification of the assembly.
Further in accordance with the present invention, a method for discontinuing application of laser radiation to a thermoplastic projection when the projection collapses to a predetermined displacement with respect to a reference position is disclosed. The method includes the steps of defining the reference position, and tracking a collapse position for the projection. A difference between the reference position and the collapse position is calculated and compared to the predetermined displacement.
The present invention also provides a laser staking system for deforming a projection of a workpiece and a laser joining system for joining an assembly of parts. Each system has a laser system, an actuation system, and a controller. The laser system generates a predetermined level of laser radiation based on radiation control signals. The actuation system directs the predetermined level of radiation to the parts and contacts the parts with a laser head based on forced control signals. The actuation system further generates position feedback based on a position of the laser head, where the position feedback includes a reference position. The controller communicates with the laser system and the actuation system, and generates the radiation control signals and the force control signals based on the position feedback from the actuation system. One of the radiation control signals causes the laser to discontinue generation of the laser radiation when the parts collapse to a predetermined displacement with respect to the referenced position.
BRIEF DESCRIPTION OF THE DRAWINGS
The various advantages of the present invention will become apparent to one skilled in the art by reading the following specification and subjoined claims and by referencing the following drawings in which:
FIG. 1 is a block diagram of a laser staking system in accordance with the present invention;
FIG. 2 is a block diagram of a controller in accordance with the present invention;
FIG. 3 is a block diagram of a controller actuation control module in accordance with the present invention;
FIG. 4 is a block diagram of a controller laser control module in accordance with the present invention;
FIG. 5 is a circuit schematic of a laser system in accordance with the present invention;
FIG. 6 is a cross-sectional side view of a laser head at an absolute initial position in accordance with the present invention;
FIG. 7 is a cross-sectional side view of a laser head in an initial projection position in accordance with the present invention;
FIG. 8 is a cross-sectional side view of a laser head in a position where the projection has collapsed to a predetermined displacement with respect to a reference position;
FIG. 9 is a flowchart of a computerized method for deforming a projection of a workpiece in accordance with the present invention;
FIG. 10 is a flowchart of a process for discontinuing application of laser radiation to a thermoplastic projection when the projection collapses to a predetermined position in accordance with the present invention; and
FIG. 11 is a cross-sectional side view of a laser head with respect to a TTIr welding operation in accordance with the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIG. 1, the preferred laser joining system 20 for joining an assembly of parts, or in one embodiment, for deforming a thermoplastic projection 22 of a workpiece is shown. It will be appreciated that while the system 20 is described with respect to a staking process as applied to projection 22 , the present invention can be readily modified for non-staking processes as applied to any assembly of thermoplastic parts.
Accordingly, the following description of the deformation of the projection in a staking system and the measurement of the projection collapse should be understood to apply equally to the displacement or collapse that may occur during through transmission welding of a first part that is transparent to laser radiation and a second thermoplastic part that absorbs the radiation. The joining system 20 includes a laser system 40 , an actuation system 60 , and a controller 80 . The laser system 40 generates a predetermined level of laser radiation based on radiation control signals. For the purposes of this invention, the laser radiation may be of any frequency or wavelength sufficient to induce the desired melting and temperature control of the thermoplastic projection 22 . Notwithstanding the general applicability of the invention over a variety of frequencies and wavelengths, for staking applications using thermoplastic projections such as that described herein, the wavelength of the laser radiation is preferably within the range of about 600 to about 1000 nm. The actuation system 60 directs the laser radiation to the projection 22 and contacts the projection 22 with a laser head based on force control signals. Contacting the projection 22 with the laser head results in a predetermined weld force. The combination of the predetermined weld force and the predetermined level of laser radiation causes the projection 22 to collapse such that a workpiece 24 may be staked to a part 26 (FIG. 8 ).
The actuation system 60 generates position feedback based on a position of the laser head, where the position feedback includes a reference position of the laser head. It can be seen that the controller 80 communicates with the laser system 40 and the actuation system 60 . The controller 80 generates the radiation control signals and the force control signals based on the position feedback from the actuation system 60 . When the projection 22 collapses to a predetermined displacement with respect to the reference position, one of the radiation cortrol signals from the controller 80 causes the laser system 40 to discontinue generation of the laser radiation. Controlling the laser radiation based on position feedback represents a significant improvement over time-based laser joining approaches.
Turning now to FIG. 2, one embodiment of the controller 80 is shown in greater detail. Specifically, the controller 80 can include a reference module 82 for defining the reference position of the head 46 , and a dynamic collapse module 84 for tracking a collapse position for the projection 22 (FIG. 1) by monitoring the position of the head. Thus, the position feedback also includes a dynamic collapse position for the projection 22 . A summation module calculates the difference between the reference position and the collapse position, and a comparison module 86 compares the difference to a predetermined displacement that is specific to the particular application. It is preferred that a displacement database 88 contains the predetermined displacement information required for comparison module 86 to make its comparison. The information in the displacement database 88 can relate to all potential parts and assemblies to be joined by the joining system 20 . The comparison module 86 signals a laser control module 96 to discontinue the radiation when the difference between the reference position and the collapse position equals the predetermined displacement.
It will be appreciated that the present invention further provides for various modes of defining the reference position. Thus, a mode selector 89 is included with the controller to provide a mechanism for transitioning between the modes. For example, the reference module 82 can record an initial projection position as the reference position, or an absolute initial position as the reference position. The various modes of defining the reference position will be discussed in greater detail below.
It will further be appreciated that the controller 80 can also include an actuation control module 90 for communicating constant weld force data or variable weld force data to the actuation system 60 . As a result, while the radiation and weld forces are referred to herein based upon “predetermined” levels, the magnitude of these values may be constant or variable throughout the weld process. By way of example, FIG. 3 demonstrates that the actuation control module 90 of the controller 80 can have a constant actuation sub-module 92 for generating the constant weld force data and a variable actuation sub-module 94 for generating the variable weld force data. Similarly, FIG. 4 demonstrates that the laser control module 96 of the controller 80 can include a constant radiation sub-module 98 for generating constant radiation data and a variable radiation sub-module 99 for generating variable radiation data.
FIG. 5 demonstrates one embodiment of the laser system 40 . Specifically, it can be seen that the laser system 40 uses a diode array 42 to generate the laser radiation. The laser radiation from the diode array 42 can be piped to a laser head 46 (FIGS. 6-8) via optical fibers or other suitable optical transmission mechanism. A laser sub-system 44 acts as a “black box” and provides current to the diode array 42 in response to a radiation control (drive) signal from the controller 80 .
As will be discussed below, the laser head of the laser head 46 has a pressure transducer for providing the actuation system 60 (FIG. 1) with force feedback. This allows the actuation system 60 to determine when the projection 22 has been contacted, as well as how much force is being applied. When the force feedback indicates that the projection 22 has been contacted and the joining system 20 is operating in collapse mode (to be described later), the actuation system 60 reports an initial projection position back to the controller 80 . In such case, the initial projection position is defined as the reference position. The actuation system 60 uses an encoder (not shown), which is also mounted in the laser head 46 , to provide the controller 80 with the necessary position data. Both the transducer and the encoder can be commercially available “off-the-shelf” parts and are well known in the art.
Turning now to FIGS. 6-8, the joining and laser staking process of the present invention is demonstrated in greater detail. With specific reference to FIG. 6, it can be seen that a workpiece 24 having a projection 22 is to be joined with an adjacent part 26 . The laser head 46 has a die 48 and a pressure sensing mechanism such as a transducer 49 . As already discussed, the reference position can be defined based on either an absolute initial position 50 or an initial projection position 52 . If the reference position is defined based on the absolute initial position 50 , the joining system 20 is said to be operating in the “absolute mode.”
FIG. 7 demonstrates movement of the laser head 46 toward the projection 22 until contact is made at an initial projection position 52 which can be defined as the reference position when the system is operating in the “collapse mode”. In the collapse mode, the transducer 49 reports a contact force back to the actuation system 60 . When the contact force reaches a predefined trigger force, the position of the laser head is stored as the initial projection position 52 . It will also be appreciated that the trigger force can serve as a mechanism for beginning the laser radiation 41 .
During welding, the laser head 46 applies the predetermined level of laser radiation to the projection 22 until the projection 22 collapses to the predetermined displacement shown in FIG. 8 . If the absolute initial position 50 is used as the reference position (i.e., the absolute mode), the predetermined displacement 54 will serve as the distance for discontinuing application of the laser radiation 41 (FIG. 7 ). On the other hand, if the initial projection position 52 is used as the reference position (i.e., the collapse mode), predetermined displacement 56 will serve as the distance for discontinuing application of the laser radiation 41 . It should be appreciated that the laser head 46 also applies the weld force while the projection 22 is being collapsed, that is, as the laser head 46 moves from its initial projection position to its predetermined displacement. The laser head 46 may be maintained in its predetermined displacement position for a period of time following termination of the laser radiation so as to allow the projection to solidify while being constrained by the die configuration. During this solidification period, which may be programmed by the user, the weld force is generally decreased to maintain the projection position.
Turning now to FIG. 9, a computerized method 100 for joining an assembly of parts is shown for programming purposes. It will be appreciated that the present invention can be implemented in either hardware or software, or both, using techniques well known in the art. Specifically, it can be seen that at step 110 the reference position is defined. At step 120 a predetermined weld force is applied to the assembly, and at step 130 a predetermined level of laser radiation is applied to the assembly. As already discussed, the predetermined weld force and the predetermined level of laser radiation cause the assembly to collapse. At step 140 it is determined whether the assembly has collapsed to a predetermined displacement with respect to the reference position. If so, the application of the laser radiation is discontinued at step 150 . If the predetermined displacement has not been reached, the predetermined weld force and laser radiation continue to be applied. One embodiment of the present invention further includes the step 160 of determining whether a predetermined time period has expired for the purposes of discontinuing application of the predetermined weld force at step 170 . This allows the assembly to solidify.
FIG. 10 shows the step 140 of determining whether the predetermined displacement has been reached in greater detail. Specifically, at step 142 a collapse position for the assembly is tracked. This can be achieved by merely recording the position data provided by the actuation system encoder. At step 144 a difference between the reference position and the collapse position is calculated. The difference is then compared to the predetermined displacement at step 146 . The laser radiation is terminated and the force discontinued when the difference is greater than or equal to the predetermined displacement. A cool down period may also be applied for solidification.
It is important to note that while the present invention has generally been described with respect to thermoplastic material, any material in which the laser radiation can have a frequency sufficient to induce melting of the material can be used. Moreover, as is generally noted above, the distance mode of controlling when the laser radiation and pressure is discontinued may be applied to various other applications including TTIr welding. For completeness, the beginning of a representative TTIr welding application is generally illustrated in FIG. 11 . In this application, the laser radiation is nearly one hundred percent transparent to a first clear part 70 but absorbent relative to a second absorbent part 72 . In most TTIr applications, the second absorbent part 72 is black in color. A series of diodes are commonly positioned in side-by-side relation in a diode array to produce a radiation line that matches the contour of the desired weld line. The laser radiation passes through the first clear part 70 and impacts the second part 72 which is preferably an 25 absorbent polymer. As the second part 72 is heated to a critical melting temperature, the head 46 is displaced to press the two parts together. The distance that the head 46 is displaced is again the parameter that is measured to discontinue the radiation and pressure. The pressure may be maintained as the weld or bond cools to form the joint. It should be appreciated that the above discussed control techniques have equal applicability to the TTIr applications, as well as various other laser welding techniques.
Those skilled in the art can now appreciate from the foregoing description that the broad teachings of the present invention can be implemented in a variety of forms. Therefore, while this invention has been described in connection with particular examples thereof, the true scope of the invention should not be so limited since other modifications will become apparent to the skilled practitioner upon a study of the drawings, specification and following claims.
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A laser joining system deforms a workpiece projection based on collapse of the projection to a predetermined displacement. The laser joining system has a laser system for generating a predetermined level of laser radiation based on radiation control signals. An actuation system directs the laser radiation to the projection and contacts the projection with a laser head based on forced control signals. The actuation system also generates position feedback based on a position of the laser head, wherein the position feedback includes a reference position of the laser head. The joining system further includes a controller communicating with the laser system and the actuation system. The controller generates the radiation control signals and the force control signals based on the position feedback. When the projection collapses to a predetermined displacement with respect to the referenced position, one of the radiation control signals causes the laser system to discontinue generation of the laser radiation. Controlling laser radiation on the basis of collapse distance allows improved consistency and reduced rework costs.
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RIGHTS OF THE GOVERNMENT
The invention described herein may be manufactured and used by or for the Government of the United States for all governmental purposes without the payment of any royalty.
BACKGROUND OF THE INVENTION
This invention relates generally to the field of stator vane assemblies in gas turbine or turbojet engines, and more particularly to an improved mounting assembly for impingement cooling plates.
In conventional gas turbine engines, gases, generally atmospheric air, are compressed in a compression section of the engine and then flowed to a combustion section where fuel is added and the mixture burned to add energy to the flowing gases. The now high energy combustion gases are then flowed to a turbine section where a portion of the energy is extracted and applied to drive the engine compressor.
The turbine section includes a number of alternate rows of fixed stator vanes and moveable rotor blades. Each row of stator vanes directs the combustion gases to a preferred angle of entry into the downstream row of rotor blades. The rotor blades in turn extract energy from the combustion gases for driving the engine compressor.
The combustion gases are very hot, creating a need for cooling of the stator vanes and turbine blades. Part of the cooling requirements for the stator vanes is provided by passing cooling air over the base of the platform to which each stator vane is attached. For more efficient cooling, an impingement cooling plate is placed between the base of each platform and the cooling air source. The impingement cooling plates are perforated so that the cooling air is redirected to form jets of air impacting perpendicularly to the platform bases. This increases the cooling over what would result if the cooling air merely passed over the base of each platform. Other designs align the perforation holes to direct the jets of cooling air in other advantageous directions; for example, to direct cooling air to particular hot spots.
Prior art impingement cooling plates are typically welded to the platform bases at the plate edges. These welds add a manufacturing expense and create a thermal fight between the plate and the platform when the turbine is operated. The thermal fight can cause weld cracks. The welds also make repairs more difficult.
With the foregoing in mind, it is, therefore, a principal object of the present invention to provide an impingement cooling plate mounting assembly with a lower manufacturing cost, easier repairability and increased reliability over welded-in-place impingement cooling plates.
SUMMARY OF THE INVENTION
In accordance with the foregoing principles and objects of the present invention, a novel mounting assembly for impingement cooling plates on turbine stator vane platforms is described which utilizes retaining flanges and cooling pins to provide a snap-fit for a flexible sheet metal impingement cooling plate. The snap fit provides positive contact between the impingement cooling plate and the retaining flanges and between the impingement cooling plate and the cooling pins.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will be more clearly understood from a reading of the following detailed description in conjunction with the accompanying drawings.
FIG. 1 is a schematic drawing of a gas turbine engine showing the location of the turbine stator vane assemblies.
FIG. 2 is a cross-sectional view of an example prior art turbine stator vane platform.
FIG. 3 is a schematic cross-sectional drawing of a view taken along line A--A of FIG. 1 of one row of turbine stator vane assemblies only.
FIG. 4 is a cross-sectional view of turbine stator vane platform incorporating the present invention.
FIG. 5 is a perspective view of the turbine stator vane platform incorporating the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Referring now to FIG. 1 of the drawings, there is shown a gas turbine or turbojet engine 10, which has an air inlet 11, a compressor section 12, a combustion section 13 enclosing combustion chambers 14, a turbine section 15, and an exhaust duct 16.
In operation, air enters the engine 10 through the air inlet 11, is compressed as it passes through the compressor section 12, is heated in a power generating function by combustion chambers 14 as its passes through the combustion section 13, then passes through the turbine section 15 in a power extraction function, and, finally, is exhausted in jet fashion through the exhaust duct 16. The compressor section 12 derives its power from a shaft connection to the turbine section 15. The turbine section 15 includes a plurality of alternate rows of rotor blades 17 and stator vanes 18. Each row of stator vanes, comprised of a plurality of turbine vane assemblies connected together to form a fixed ring, directs working medium gases from the combustion section 13 into a downstream rotatable ring of rotor blades 17. The rotor blades 17 then extract energy from the combustion gases to rotate the shaft that drives the compressor section 12.
FIG. 2 shows a cross-sectional view of an example of the bottom portion of a prior art turbine stator vane 20, which has a blade-shaped vane 21 mounted on a wider platform 22, pin fins 24, and an impingement cooling plate 25. The platform further includes wall-like extensions 23. The impingement cooling plate includes holes 26, and is welded to the platform 22 by welds 27.
FIG. 3 shows a schematic cross-sectional view taken along line A--A of FIG. 1 of a row of turbine stator vane assemblies. The stator vane assemblies are arranged with each vane platform 22 abutting its adjacent vane-carrying platform at a slight angle to their vertical axes so that a sufficient number of stator vanes and platforms form a ring. In a typical gas turbine, the angle between adjacent platforms is such that the ring has the stator vanes facing inward and the platforms facing outward and attached to the inside circumference of the outer wall assembly of the gas turbine. In most gas turbine engines, the vanes are additionally connected at their other ends, as shown by the representative dashed line 19, to form an annular path for the combustion gases.
In operation, other passageways (not shown) deliver cooling air to the channel area beneath the impingement cooling plate 25 at a higher pressure than the air between the impingement cooling plate and the bottom of the platform. The higher pressure forces air through the holes 26 which redirect the cooling air into jets which impinge upon the bottom of the platform 22, thereby cooling the platform 22 which has absorbed heat conducted from the vane 21 in contact with the hot combustion gases from the combustion section 13. The impingement process increases the efficiency of the cooling process over simple surface flow cooling by providing greater cooling for the same amount of air transport. The efficiency is a factor of both hole size and the distance of the holes from the surface to be cooled. The pin fins 24 serve to both hold the impingement cooling plate at the optimium distance from the platform surface and to provide additional surface area for contact with the cooling air and to thereby improve cooling.
Referring now to FIGS. 4 and 5, there is shown a cross-sectional and a perspective view of the bottom of a turbine stator vane 30 assembly incorporating the present invention. The vane assembly has a blade-shaped vane 31, a platform 32 with wall-like extensions 33, cast in place pin fins 34, and an impingement cooling plate 35. The platform extensions 33 additionally include cast in place retaining flanges 37. The holes 36 are present in the impingement cooling plate 35 to redirect cooling air to the bottom of the platform as previously described.
Unlike the welds of the prior art, the impingement cooling plate 35 is formed of a resilient sheet metal and snapped into place between the flanges 37 and the pin fins 34 without welds. The flanges 37 shown in this embodiment are full length, but may be interrupted, for example, as tabs, with the same good effect. An example of a suitable impingement cooling plate material is a nickle-based sheet metal alloy such as Inconel 625, of thickness 0.010 to 0.015 inches. The resiliency of the impingement cooling plate 35 material provides a positive pressure load to ensure sealing against the inside of the flanges 37 and to hold the plate in positive contact with the pin fins 34 to ensure an adequate impingement gap during operation. The continuous positive pressure sealing eliminates the manufacturing difficulty of welding the impingement cooling plate in place and avoids the concern with the thermal fight between the weld and the plate and platform causing cracks in the weld. In addition to the inherent increased reliability of this new design, repairs, if ever needed, are made much simpler by this snap-in design.
It is understood that certain modifications to the invention as described may be made, as might occur to one with skill in the field of this invention, within the scope of the claims. Therefore, all embodiments contemplated have not been shown in complete detail. Other embodiments may be developed without departing from the spirit of the invention or from the scope of the appended claims.
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A turbine stator vane assembly for gas turbine or turbojet engines has an improved structure for retention of a cooling impingement plate. Two inwardly directed flanges are added to the wall-like extensions extending from the bottom of the platform upon which the vane is mounted. The cooling impingment plate is resiliently snapped into place between pin fins on the bottom of the platform and the flanges.
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This application is a continuation-in-part of design patent application Ser. No. 29/100,830 filed on Feb. 10, 1999 and still pending.
BACKGROUND OF THE INVENTION
The present invention relates to a currency bank. More particularly, the instant invention relates to a novelty type currency bank in which it appears as if currency that is being fed into the bank is shredded whereas, in reality, it is held in a currency compartment in the bank.
A need has existed for a novelty bank in which currency that is fed into the bank appears to be shredded but in reality is stored.
Accordingly, it has been considered desirable to develop a new and improved currency bank which would meet the above-stated needs and others.
BRIEF SUMMARY OF THE INVENTION
The present invention relates to a currency bank.
More specifically, the instant invention comprises a currency bank having a housing with an inlet and an opening. A shredded currency mechanism is located in the housing and selectively appears in the opening. A feed mechanism is provided for feeding associated currency into the housing at the inlet. A timing assembly is provided for activating the shredded currency mechanism when the feed mechanism is activated so that it appears that the associated currency being fed into the housing is being shredded.
Preferably, the shredded currency mechanism comprises a motor, a gear train coupled to the motor and a belt assembly operatively connected to the gear train. Preferably, the belt assembly comprises a pair of belts and a plurality of gears around which the pair of belts is looped. If desired, the plurality of gears can comprise a spaced upper pair of gears mounted on a first common shaft and a spaced lower pair of gears mounted on a second common shaft. The shredded currency mechanism can further comprise a cross bar connected to the pair of belts and a shredded currency element secured at one end to the cross bar.
Preferably, the motor comprises an electric motor and there is also provided a source of electric power for the motor. If desired, the source of electric power can comprise batteries located in a battery compartment in the housing.
If desired, a speaker can be located in the housing wherein the timing mechanism also activates the speaker. Also, if desired, a photograph holder can be located on the housing. Preferably, a currency compartment is located in the housing for holding associated currency after it has passed through the feed mechanism. A door located on the housing provides access to the currency compartment.
Preferably, the timing assembly comprises a control circuit, a first timing element for actuating the feed mechanism and a second timing element for deactivating the shredded currency mechanism. If desired, the first timing element can comprise a finger located in a currency inlet slot of the housing. The second timing element can comprise a protrusion located on an element of the shredded currency mechanism.
In another aspect of the present invention, a method of operating the currency bank is provided.
More particularly, in accordance with this aspect of the invention, the method comprises the steps of providing a housing having an inlet in a currency compartment and feeding a piece of currency into the inlet. A shredded currency element is moved past the window in the housing. Thereafter, the piece of currency is deposited into the currency compartment.
One advantage of the present invention is the provision of a novelty currency bank.
Another advantage of the present invention is the provision of a novelty currency bank in which currency that is pulled into the bank appears to be shredded but is, in reality, deposited into a currency compartment in the bank.
Still another advantage of the present invention is the provision of a timing mechanism in a currency bank which starts the motion of a piece of shredded currency past a window at the same time that a piece of currency is fed into an inlet slot of the currency bank.
Yet another advantage of the present invention is the provision of a novelty currency bank with a speaker and a voice chip so that an audible message is played when a piece of currency is fed into the bank.
A further advantage of the present invention is the provision of a currency bank with a window in which a photograph can be displayed.
A still further advantage of the present invention is the provision of a currency bank which is digitally controlled so as to activate and deactivate an electric motor. The motor serves both to pull currency into the bank and to start the motion of a piece of shredded currency past a window in the bank. Preferably, switches are used to activate and deactivate the motor.
Still other benefits and advantages of the present invention will become apparent to those of average skill in the art upon a reading and understanding of the following detailed specification.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention may take form in certain parts and arrangements of parts, a preferred embodiment of which will be described in detail in this specification and illustrated in the accompanying drawings which form a part hereof and wherein:
FIG. 1 is a perspective view of a currency bank according to a preferred embodiment of the present invention, with a part partially broken away for clarity;
FIG. 2 is a rear elevational view of a currency bank of FIG. 1 with a part partially broken away for clarity;
FIG. 3 is a top plan view of the currency bank of FIG. 1;
FIG. 4 is a bottom plan view of the currency bank of FIG. 1 with a part partially broken away for clarity;
FIG. 5 is a perspective view of the currency bank of FIG. 1 with a part partially broken away for clarity;
FIG. 6 is an exploded perspective view of the currency bank of FIG. 1;
FIG. 7 is a front elevational view of the currency bank of FIG. 1 with a front housing half removed for clarity;
FIG. 8 is a left side cross sectional view of the currency bank of FIG. 1;
FIG. 9 is a flow chart illustrating the steps performed by the currency bank of FIG. 1;
FIG. 10 is a diagrammatic view of the control elements of the currency bank of FIG. 1;
FIG. 11A is an enlarged side elevational view of the belt of the currency bank of FIG. 6;
FIG. 11B is a greatly enlarged side elevational view of a portion of the belt of FIG. 11A; and,
FIG. 12 is a circuit diagram of another control assembly for the currency bank according to the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings wherein the showings are for purposes of illustrating preferred embodiments of the present invention only and not for purposes of limiting same, FIG. 1 illustrates a currency bank A having a housing 10 with a first half 12 and a second half 14 . A picture opening 20 is provided in the first half 12 . Also, spaced from the picture opening are a plurality of speaker apertures 22 which comprise a speaker grille. As shown in FIG. 8, a top indentation 24 is located on the first half along with a bottom indentation 26 .
With reference now to FIG. 6, the second half 14 comprises a currency compartment opening 30 which is covered by a selectively openable door 32 . Also provided is a top indentation 34 and a bottom indentation 36 .
Covering the picture opening 20 and the housing first half 12 is a window 40 . The window is selectively removable so that a user of the currency bank A can position a user selected picture 42 behind the window. To this end, a set of four corners 44 are provided on a first frame 50 . The four corners of the picture 42 can be tucked behind the corners 44 so as to secure the picture in place.
The front frame 50 is positioned adjacent a main frame 52 . These elements are secured together with the first and second housing halves 12 and 14 . To this end, a plurality of spaced ears 54 are provided on the front frame. These ears are aligned with spaced ears 56 located on the main frame and mounts 58 located on the second half. Aligned with all of the foregoing ears and mounts are mounts 60 (see FIG. 8) located on the first half. Suitable fasteners 62 (FIG. 2) secure the front frame 50 , main frame 52 , first half 12 and second half 14 to each other.
Positioned in the respective top indentations 24 and 34 of the first and second housing halves 12 and 14 is a currency entrance frame 70 . With reference now also to FIG. 3, a slot 72 is defined in the entrance frame 70 . The slot is sized so as to accommodate a variety of sizes of bills or currency such as U.S. dollars, British pounds, Mexican Pesos and the like. Extending into the slot 72 are a front finger 74 and a pair of rear fingers 76 . In the preferred embodiment, the front finger 74 is moveable, whereas the rear fingers 76 are stationary. However, it should be apparent to those of average skill in the art that all of the fingers can be moveable if so desired. Alternatively, the rear fingers 76 could be moveable with the front finger being stationary. With reference now also to FIG. 7, the front finger 74 is wired to a front switch 78 . Thus, when the front finger is depressed, the switch is activated. The signal from the front switch is transmitted via suitable wiring to a suitable digital control chip 80 (FIG. 10) located in the housing.
With reference again to FIG. 6, positioned adjacent the switch 78 are a pair of front rollers 82 mounted on a common shaft. The front rollers are rotatably mounted via the shaft on the front frame 50 . Located adjacent the front rollers are a pair of rear rollers 84 mounted on a common shaft. The shaft is rotatably mounted on a pusher plate 86 . As is evident from FIG. 3, the front and rear rollers 82 and 84 are aligned with each other.
The pusher plate 86 is resiliently biased forward by a spring (not visible) so that the rollers 82 and 84 normally contact each other. They form between them a nip for accommodating a piece of currency.
Positioned below the sets of rollers 82 and 84 is a pair of spaced upper belt gears 90 mounted on a common shaft. Spaced therefrom is a pair of spaced lower belt gears 92 also mounted on a common shaft. Looped around the upper and lower belt gears 90 and 92 are a left belt 94 and a right belt 96 . It is apparent that these belts are endless belts. With reference now also to FIG. 5, a cross bar 100 is mounted on the left and right belts 94 and 96 . A piece of shredded currency 102 is secured at a proximal end 104 to the cross bar 100 . The proximal end of the shredded currency is looped around the cross bar 100 so as to form a single element. However, a distal end 106 of the currency presents a shredded appearance. The distal end is not secured to the pair of spaced belts.
With reference now again to FIG. 8, a motor 110 is located in the housing 10 . The motor includes an output shaft 112 which is connected to a lower gear train 113 . The lower gear train 113 comprises a worm gear 114 which is mounted on the output shaft 112 , an intermediate gear 115 and a primary drive gear 116 . The drive gear 116 is coupled to the lower belt gears 92 . The lower gear train 113 drives the pair of belts 94 , 96 and, hence, the shredded currency 102 . A positive drive is provided. To this end, there are teeth 118 located on the lower belt gears 92 and teeth 120 located on the upper belt gears 90 . These teeth engage corresponding teeth 122 on the belts 94 and 96 .
Coupled to the shaft of upper belt gears 90 is an upper gear train 126 . With reference again to FIG. 6, the upper gear train 126 drives the front rollers 82 . When the motor 110 rotates the lower gear train 113 , and hence, the left and right belts 94 and 96 , the upper gear train 126 is also rotated. In this way, the front rollers 82 are correspondingly rotated. The rear rollers 84 are freely rotatable and will move when they are in contact with the moving front rollers 82 .
Preferably, the motor 110 is an electric motor. Electricity is provided for the motor 110 via a battery compartment 130 . As is illustrated in FIG. 4, suitable batteries 132 are located in the battery compartment 130 . Preferably, a door 134 selectively closes the battery compartment.
With reference again to FIG. 8, a currency storage area 140 is located beneath the front and rear rollers 82 and 84 and somewhat behind them. With reference now to FIG. 5, when a piece of currency 142 is pulled into the housing 10 at the nip formed between the front and rear rollers 82 and 84 , the currency is deposited in the storage area 140 . At the same time, due to the coordinated movement of the shredded currency 102 via the cross bar 100 , when the belts 94 and 96 are actuated, it appears as if the currency 142 is being shredded.
With reference again to FIG. 7, a speaker 146 can be mounted on the housing 10 . The speaker 146 is located directly behind the speaker apertures 22 illustrated in FIG. 1 . Electrically connected to the speaker 146 is a voice chip 148 (FIG. 10 ). The control chip 80 selectively activates the voice chip 148 , and hence, the speaker. Alternatively, operation could be controlled more simply by an off switch and an on switch as illustrated in FIG. 12 . Preferably, the operation of the speaker is coordinated with the rotation of the belts 94 and 96 . The speaker can be actuated during the time when the currency is pulled into the housing and the shredded currency is moving past the window. In one embodiment, the speaker broadcasts the message: “ha, ha, ha . . . easy come, easy go.” It is evident that the speaker 146 could broadcast whatever message is encoded in the voice chip 148 .
With reference again to FIG. 6, a respective protrusion or bump 150 , 152 is provided on each of the belts 94 and 96 . In one preferred embodiment, the bump 150 comprises a pair of spaced elements. With reference now particularly to FIGS. 11A and 11B, the bump 150 can comprise a first element 160 and, slightly spaced therefrom, a second element 162 and a third element 163 . The first element 160 serves a timing function and sends an initial signal to the control chip 80 when it activates a second switch 164 (FIG. 10) to stop rotation of the motor. The second and third elements 162 and 163 serve as a means for spacing the front and rear rollers 82 and 84 away from each other. This is done by the bumps pushing the pusher plate 86 , and hence the rear rollers 84 , away from the front rollers, against the bias of the spring which urges the upper end of the pusher plate 86 forward. Also, the second bump element 162 holds the bill shaft 100 . A plurality of slits 166 is cut into the underside of the several bump elements in order to allow the elements to flex as the belt 90 travels around the upper and lower gears 90 , 92 . This is best shown in FIG. 11 B. It should be apparent to those in the art that a single long element bump could be employed instead of the two element design illustrated in FIGS. 11A and 11B.
As mentioned, the bumps serve a timing function. Also serving a timing function is the front finger 74 (FIG. 3 ). The front finger serves as a first timing element, whereas the bumps 150 , 152 serve as a second timing element in controlling the operation of the motor, and hence, the currency bank.
With reference now to FIG. 9, the operation of the currency bank will now be described. Operation begins when a piece of currency, such as the bill 142 , is inserted into the housing 10 . A proximal edge of the bill activates the front switch 78 by a movement of the front finger 74 . When the front switch is activated, a signal is sent to the control chip 80 which then starts the motor 110 as is illustrated in block 204 . The belts 94 and 96 then begin to move past the window 40 as is illustrated in block 206 . The rollers 82 and 84 , since they form a nip, grab the currency 142 and pull it into the currency storage area 140 . At the same time, the shredded currency 102 travels past the window 40 . This coordinated movement simulates the shredding of the currency 142 to the observer whereas, in reality, the currency is being preserved.
During the time when the shredded currency 102 is moving past the window and the currency 142 is being taken into the housing 10 , an impulse is sent to the voice chip 148 on the circuit board thereby activating the speaker 146 as shown in box 212 . Subsequently, the currency is pulled entirely through the front and rear rollers 82 and 84 and is deposited into the storage area 140 as shown in block 214 . Thereafter, the front switch 78 turns off as shown in block 260 . At this time, the belts 94 and 96 with the shredded currency 102 return to their original position as shown in block 218 . The bumps 150 and 152 on the pair of belts 94 and 96 move the pusher 86 back, against the biasing of the spring, turning off the back switch 164 as shown in block 220 . More importantly, the bumps keep the front and rear rollers separated. Such separation is necessary in order that a nip is formed by the facing rollers when a piece of currency is inserted between the rollers and trips the front switch. This action brings the opposed rollers together grabbing the currency and preventing its removal. When the back switch is off, the motor 110 stops as shown in block 222 . This brings the process to an end.
The main housing 52 and the pusher plate 86 cooperate to define a screen behind the window 20 . In this way, the shredded currency 102 can not be seen as it is moved along the belts 94 , 96 behind the picture 42 back to the start position of the shredded currency.
The invention has been described with reference to several preferred embodiments. Obviously, modifications and alterations will occur to others upon a reading and understanding of the preceding detailed description. It is intended that the invention be construed as including all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalence thereof.
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A currency bank includes a housing having an inlet and an opening. A shredded currency mechanism is located in the housing and selectively appears in the opening. A feed mechanism is provided for feeding associated currency into the housing at the inlet. A motor powers the shredded currency mechanism and the feed mechanism. A timing assembly is provided for activating the shredded currency mechanism when the feed mechanism is activated by an associated piece of currency so that it appears that the associated currency being fed into the housing is being shredded.
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CROSS-REFERENCE TO RELATED APPLICATIONS
The present application is a continuation of International Application No. PCT/CN2007/002843, filed Sep. 28, 2007, which claims the benefit of Chinese Patent Application No. 200610140661.X, filed Sep. 29, 2006, both of which are hereby incorporated by reference in their entireties.
FIELD OF THE INVENTION
The present invention relates to mobile communication technologies, and in particular, to a method, terminal, server and system for processing a notification message.
BACKGROUND OF THE INVENTION
After decades of years of development, more and more people benefit from the mobile communication. However, the services provided by the mobile communication are still mainly voice services and message services. With the rapid development of the Internet, a large number of multimedia services come forth, and people are gradually requiring that the multimedia services can be supported by the mobile communication. Some multimedia applications provided by the Internet require that multiple terminal users receive the same data simultaneously, such as the mobile video, television broadcasting, video conference, online education and interaction game. The mobile video gradually becomes a hot subject at home and abroad.
In the present mobile video technology, an important technology is the application layer technology which is independent from the bearer network. The application layer technology includes aspects such as audio/video encoding of the channel content, electronic service guide (ESG), content protection technology as well as service authentication, user management and charging. The relevant standardization organizations include the Convergence of Broadcast and Mobile Service (CBMS) work group of the Digital Video Broadcast (DVB) organization, the Broadcast (BCAST) work group of the Open Mobile Alliance (OMA) organization, etc. With the application layer technology, the available contents of the IP programs on the Internet may be used directly and broadcast to terminal users via a broadcast network, so that the existing content resources may be protected to the greatest extent.
FIG. 1 is a schematic diagram showing an implementation of the networking of the broadcast service in the prior art. As shown in FIG. 1 , a broadcast application server locates in the IP network and is connected to a broadcast network via IP encapsulation equipment (IPE), so as to realize key functions such as real-time program broadcasting, assembling and transmitting of the electronics service guide, encrypting of the program contents and transmitting of the notification message. A client operating server connected to an exchange network is adapted to provide program purchasing information for the terminal user, receive and process the purchasing request of the user and provide service for the user. The terminal has the capability of accessing the broadcast network and exchange network simultaneously. The DVB-H technology, T-DMB technology and so on may be employed in the broadcast network, and the Code Division Multiple Access (CDMA) technology, Global System for Mobile Communication (GSM) technology and so on may be employed in the exchange network. Different notification service servers broadcast notification messages of the corresponding services to the terminal via the broadcast application server.
The electronic service guide (ESG) is constituted by a plurality of different fragments according to the internal logic relations of these fragments. As shown in FIG. 2 , the purchase item and purchase channel belong to the service provision, whereas the service bundle, service, schedule event and content belong to the service core, and the service acquisition and session description belong to the service access, where the session description does not belong to the fragments. With respect to different implementations, the structure of ESG may be different. The specific meaning of each fragment in FIG. 2 is as shown in Table 1. The line connection relations between the fragments represent the corresponding relations between different fragments. For example, the relation between the service and schedule event is that one service fragment may correspond to 0 to n fragments of the schedule event.
TABLE 1
Example of specific meanings of the fragments
Fragments
of ESG
Meaning
Service Bundle
Collection of services, which is corresponding to the
purchase item
Service
Collection of services
Service
Fragment of Service Acquisition is associated with the
Acquisition
session description of the transmission stream of program
content and indicates the distribution manner. For a
terminal, the Service Acquisition indicates the method
and approach to access the transmission stream
of program content
Schedule Event
Time table of the content or service
Content
The content or program included in a service
Purchase Item
Purchase unit visible to a terminal user
Purchase
Approach and address for purchasing the purchase item
Channel
A notification is used to send messages to the terminal user in a mobile broadcast system to notify the terminal user of events that are about to happen, and the terminal user or terminal performs a corresponding processing. The messages include, but not limited to: message of emergencies; notification message relevant to the system, such as a message for notifying the terminal user that a function of the system fails; event message relevant to a program, such as relevant material of a program actor; and notification message of software update, etc.
The notification message broadcasted has a fixed structure, and the terminal can only obtain values of some fixed parameters such as service identification and time in the notification message according to the structure of the notification message, and use these values of the fixed parameters to implement specific functions such as filtering the notification message. However, because the parameters that can be carried in the notification message are very limited, and these parameters can only be fixed parameters, the information obtained by the terminal user from the notification message is very limited. Furthermore, when the terminal user configures the filtering condition, only these fixed parameters may be used as the filtering condition. Thus, the configuration of the filtering condition is limited by the fixed parameters contained in the notification message, the terminal user is not able to configure the filtering condition flexibly, and the individual demands of the terminal user cannot be satisfied.
Moreover, because the parameters contained in the notification message are very limited, the terminal user cannot quickly obtain the value of the parameter concerned, such as the value of a parameter relevant to the notification message. Thus, the notification message cannot be processed flexibly.
SUMMARY OF THE INVENTION
Various embodiments of the present invention provide a method, terminal, server and system for processing a notification message, so that more information may be provided for the terminal user via the notification message. Further, the terminal and the server cooperate with each other to implement various processing for the notification message.
A method for processing a notification message according to an embodiment of the present invention includes: sending, by a server, a notification message carrying description information to a terminal, where the description information includes a parameter; and parsing, by the terminal, the notification message according to the parameter.
A terminal for processing a notification message according to an embodiment of the present invention includes: a receiving unit, adapted to receive a notification message carrying description information, where the description information includes a parameter; and a processing unit, adapted to parse the notification message according to the parameter.
A server for processing a notification message according to an embodiment of the present invention includes: a message generating unit, adapted to add description information into the notification message; and a sending unit, adapted to send the notification message carrying the description information.
A system for processing a notification message according to an embodiment of the present invention includes a server and a terminal. The server is adapted to add description information into the notification message, and send the notification message to the terminal; and the terminal is adapted to parse the notification message received according to a parameter contained in the description information.
In the embodiments of the present invention, the server sends a notification message carrying description information to the terminal, where the description information includes a parameter. When receiving the notification message, the terminal parses the notification message according to the parameter, where one or more parameters may be included in the description information, so that more information may be provided for the terminal via the notification message, and the terminal may promptly obtain the information required.
Further, when the description information is added in the notification message, the terminal may perform various processing on the received notification message, and realize various new functions on the terminal. For example, the terminal may implement filtering of the notification message with the filtering rules stored, the terminal user may configure the filtering rules satisfying the individual requirements of the terminal user himself, and the terminal may determine whether the parameter value in the notification message satisfies the filtering rules stored when receiving a message of a notification service, and processing the notification message accordingly, such as only store or display the notification in which the terminal user is interested. The terminal user may configure the filtering rules according to a filtering condition list containing a plurality of parameters, or the terminal or user may configure the filtering rules according to one or more parameters in the description information and the relationship between the parameters. Because various parameters may be contained in the description information, the filtering rules obtained in the embodiments of the present invention are flexible and diversified.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic diagram showing a networking for implementing a broadcast service in the prior art;
FIG. 2 is a schematic diagram showing an ESG model in the prior art;
FIG. 3 is a schematic diagram showing structured description information according to an embodiment of the present invention;
FIG. 4 is a schematic diagram showing that a terminal obtains the structure of description information via a parameter MediaLocator according to an embodiment of the present invention;
FIG. 5A is a flow chart for configuring filtering rules according to an embodiment of the present invention;
FIG. 5B is a schematic diagram showing the processing of a notification message according to the filtering rules according to an embodiment of the present invention;
FIG. 6 is a schematic diagram showing that the terminal obtains a filtering condition list via the parameter MediaLocator according to an embodiment of the present invention;
FIG. 7A is a flow chart of configuring filtering rules by the terminal according to an embodiment of the present invention;
FIG. 7B is a flow chart of processing a notification message according to the filtering rules by the terminal according to an embodiment of the present invention;
FIG. 7C is a schematic diagram showing data structure of the filtering rules stored in the terminal according to an embodiment of the present invention;
FIG. 8A shows a specific example of structure of a decision tree according to an embodiment of the present invention;
FIG. 8B is a schematic diagram showing a specific example of values of the decision tree according to an embodiment of the present invention;
FIG. 9A is a schematic diagram showing structure of a terminal processing a notification message according to an embodiment of the present invention;
FIG. 9B is a schematic diagram showing structure of a server processing a notification message according to an embodiment of the present invention; and
FIG. 9C is a schematic diagram showing structure of a system processing a notification message according to an embodiment of the present invention.
DETAILED DESCRIPTION OF THE EMBODIMENTS
In an embodiment of the present invention, a server sends a notification message carrying description information to a terminal. When receiving the notification message, the terminal processes the notification message according to parameters contained in the description information. One or more parameters may be included in the description information. The description information carried in the notification message may be structured description information, i.e., the description information includes the structure and content of the description information. Alternatively, the structure of description information may be provided to the terminal in advance, so that the description information carried in the notification message only includes the content of the description information, and the content of the description information may only be parameter values.
In a specific embodiment when the description information carried in the notification message is the structured description information, the server may use parameter information to constitute the description information according to a configured structure, and send the description information with the configured structure to the terminal. The server may structure the description information according to the format of a parameter list. The data structure of the parameter list is as shown in Table 2.
TABLE 2
Schematic data structure of structured description information
Occurrence
Parameter
Type
Number
Meaning
Data Type
ParameterList
E
0 . . . 1
Parameter
NA
list
ParameterNumber
A
1
Parameter
Integer, which indicates the number of
number
parameters
Parameter
E1
0 . . . N
Parameter
NA
ParameterIdentifier-
E2
1
Length of
Integer
Length
parameter
identifier
ParameterIdentifier
E2
1
Parameter
Character string, the length of which is
identifier
specified by ParameterIdentifierLength
ParameterEncoding
E2
1
Type of
Character string with a fixed length,
parameter
which defines the encoding mode and
value
character string of ParameterValue,
where following types are included:
string, signed short, long, Boolean,
float, double and date
ParameterValue-
E2
1
Length of
Integer
Length
parameter
value
ParameterValue
E2
1
Parameter
Character string, the encoding mode is
value
specified by ParameterEncoding, and
the length is determined by
ParameterValueLength
In the above table, E represents Element, A represents Attribute, E1 represents a first layer element, E2 represents the sub-element of the first layer element, and the rest may be deduced by analogy.
FIG. 3 illustrates structured description information according to an embodiment of the present invention. As shown in FIG. 3 , in combination with Table 2, the description information with the configured structure includes N parameters. The value of ParameterIdentifierLength determines the byte length occupied by the ParameterIdentifier, and the value of ParameterValueLength determines the byte length occupied by the ParameterValue. When receiving the notification message carrying the structured description information, the identifier of each parameter and the corresponding parameter value are determined according to the configured structure of the description information.
Alternatively, the server may also send the structure of the description information to the terminal in advance, and the terminal stores the structure of the description information. In the subsequent procedure, only the content of the description information is carried in the notification message sent to the terminal by the server. When the notification message is received, the terminal may process the content of the description information, such as determine the parameter value corresponding to the parameter identifier in the structure of the description information, according to the stored structure of the description information.
The server may send relevant information of the structure of the description information to the terminal with the data structure RelatedMaterial in the existing ESG.
When the server sends the relevant information of the structure of the description information to the terminal with the data structure RelatedMaterial, two modes, i.e., Pull mode and Push mode, may be employed. The Pull mode is initiated by the terminal. The terminal obtains the address of the structure of the description information with the parameter MediaLocator of ESG, and submits application to the server. Then the server sends the structure of the description information to the terminal according to the application of the terminal. The Push mode is initiated by the server. The server puts the structure of the description information in the ESG and sends the ESG to the terminal via the broadcast network.
Specifically, the process of sending relevant information of the structure of the description information to the terminal with the data structure RelatedMaterial may be implemented in following three modes.
Mode I: The server performs configuration to make the parameter MediaLocator in the data structure RelatedMaterial include the structure of the description information, and then sends the data structure RelatedMaterial to the terminal. The terminal obtains the structure of the description information from the parameter MediaLocator in the received data structure RelatedMaterial directly, and stores the structure of the description information. The structure of the description information may be included in the parameter MediaLocator of the data structure RelatedMaterial of the service fragment, or may be included in the parameter MediaLocator of the data structure RelatedMaterial of the content fragment, or may be included in the parameter MediaLocator of respective data structure RelatedMaterial of the service fragment and content fragment simultaneously. This mode is referred to as the Push mode.
Mode II: The server performs configuration to make a file in the structure of Auxiliary Data of ESG include the structure of the description information, performs configuration to make the parameter MediaLocator in the data structure RelatedMaterial include Uniform Resource Identifier (URI) of the file, and then sends the data structure RelatedMaterial to the terminal. The terminal obtains the URI through the parameter MediaLocator of the received data structure RelatedMaterial, finds the file corresponding to the URI in the structure of Auxiliary Data according to the URI, and obtains the structure of the description information from the file. For example, as shown in FIG. 4 , the structure of the description information is configured in a file of the structure of Auxiliary Data of ESG by the server. The URI of this file is metadataURI=“urn:dvb:ipdc:esg:FilterConstruct”. The parameter MediaLocator in the data structure RelatedMaterial sent to the terminal by the server includes a URI, this URI=“urn:dvb:ipdc:esg:FilterConstruct”. When receiving the data structure RelatedMaterial, the terminal obtains the URI in the parameter MediaLocator, finds the corresponding file in the structure of Auxiliary Data according to the URI, obtains the structure of the description information from the file, and stores the structure of the description information. The URI may be included in the parameter MediaLocator of the data structure RelatedMaterial of the service fragment, or may be included in the parameter MediaLocator of the data structure RelatedMaterial of the content fragment, or may be included in the parameter MediaLocator of respective data structure RelatedMaterial of the service fragment and content fragment simultaneously. This mode is referred to as the Push mode.
Mode III: The server performs configuration to make a file in the server include the structure of the description information, performs configuration to make the parameter MediaLocator in the data structure RelatedMaterial include a Uniform Resource Locator (URL) of effective “http”, “ftp”, “rtsp” or “tftp” addresses of this file, such as http://www.kbs.co.kr/FilterConstruct.xsd, and then sends the data structure RelatedMaterial to the terminal. The terminal obtains the URL through the parameter MediaLocator of the received data structure RelatedMaterial, and accesses the server. The terminal finds the file corresponding to the URL according to the URL, and requests the server to provide this file. The server sends the file to the terminal. Finally, the terminal obtains the structure of the description information from this file and stores the structure of the description information. The URL may be included in the parameter MediaLocator of the data structure RelatedMaterial of the service fragment, or may be included in the parameter MediaLocator of the data structure RelatedMaterial of the content fragment, or may be included in the parameter MediaLocator of respective data structure RelatedMaterial of the service fragment and content fragment simultaneously. This mode is referred to as the Push mode.
In order to achieve the object that the terminal obtains the address of the structure of the description information through ESG, other parameters including (but not being limited to) Server fragment parameter may be extended except for configuring the extended parameter MediaLocator in ESG, where the Server fragment parameter may be used to carry the structure of the description information. This structure may bear an address for obtaining the specific structure of the description information, or may bear the structure of the description information itself directly.
When the structure of the description information is stored in the terminal, the notification message sent by the server to the terminal in the subsequent procedure may only carry the content of description information. When receiving the notification message, the terminal may process the content of description information according to the stored structure of the description information, such as determine the parameter value corresponding to a parameter identifier in the structure of the description information.
For example, the XML file format of the structure of the description information that is obtained and stored by the terminal is as follows:
<element name=“MSG” type=“MSGType”>
<complexType name=“MSGType”>
<element name=“film type” type=“string”/>
<element name=“actor name” type=“string”/>
<element name=“film introduction” type=“string”/>
</complexType>
The notification message sent by the server to the terminal only carries the content of description information. The XML file format of the content of description information is as follows:
<MSG>
<film type> “action film” </film type>
<actor name> “Jackie Chan” </actor name>
<film introduction> “This story happened in ...” </film introduction>
</MSG>
Thus, the terminal can determine the specific parameter value of the corresponding parameter identifier in the structure of the description information according to the content of the description information received. In the practical application, the content of the description information may be only the parameter value, and the terminal determines the parameter identifier corresponding to the parameter value according to the stored structure of the description information. For example, with the help of the byte length occupied by each parameter identifier in the structure of the description information, the terminal extracts the parameter value of a corresponding length from the notification message as the parameter value of the parameter identifier corresponding to the length.
Further, when the server needs to provide more parameter information to the terminal via the notification message, it is required to send a new structure of the description information to the terminal, and the terminal processes the content of the received description information according to the new structure of the description information.
In the embodiment of the present invention, because the description information carried in the notification message may be structured description information, it is possible to provide the structure of the description information to the terminal in advance, and the description information carried in the notification message is only the parameter value. Thus, various parameters may be carried in the description information by configuring different structures of description information, so that the parameters obtained by the terminal through the description information carried in the notification message are more diversified and more flexible.
FIG. 5A shows a flow chart for configuring filtering rules according to an embodiment of the present invention. As shown in FIG. 5A , the specific processing procedure for configuring the filtering rules includes following steps:
Step 501 -Step 502 : A server configures a filtering condition list, and sends the filtering condition list to a terminal.
Step 503 : When the terminal receives the filtering condition list, a terminal user is prompted to configure filtering conditions and a relation between the filtering conditions according to the contents in the filtering condition list. The terminal user selects the filtering conditions and configures the relation between the filtering conditions, so as to generate the filtering rules. Then the terminal stores the filtering rules. Thus, the configuration procedure of the filtering rules is finished.
It is described above that the terminal prompts the terminal user to configure the filtering rules according to the filtering condition list from the server. However, the filtering rules may also be configured and stored in the terminal by the terminal user directly. For example, the terminal user configures the filtering rules according to one or more parameters and the relation between the parameters contained in the description information, and then the terminal stores the filtering rules. Alternatively, the filtering rules may also be provided to the terminal by the server. For example, the server configures the filtering rules according to one or more parameters and the relation between the parameters contained in the description information, and provides the filtering rules to the terminal for saving.
The terminal user may configure the filtering rules according to the filtering condition list that includes a plurality of parameters, or the terminal or server may configure the filtering rules according to one or more parameters and the relation between the parameters contained in the description information. Because the parameters contained in the description information are diversified, the filtering rules obtained in the present invention are flexible and diversified.
Step 504 -Step 505 : After the filtering rules are stored, when a notification message carrying description information sent by the server is received subsequently, the terminal processes the notification message according to the stored filtering rules and the received description information, such as filtering the parameters contained in the description information according to the stored filtering rules, determining whether the parameters in the description information satisfy the filtering rules, and processing the notification message accordingly. When the parameters in the description information are filtered according to the stored filtering rules, the terminal user may directly obtain notification message in which he is more interested, as shown in FIG. 5B .
The data structure of the filtering condition list containing filtering parameters that is sent to the terminal by the server via ESG is as shown in Table 3.
TABLE 3
Schematic data structure of the filtering condition list
Occurrence
Parameter
Type
Number
Meaning
Data Type
Filtering-
E
0 . . . 1
Filtering
NA
ConditionList
condition
list
FilteringConditionRelation
E1
1
Relation
Character string, optional relations
of filtering
between filtering rules, which may be
condition
“not”, “or”, “and”. This parameter may
include a plurality of relations.
FilterCondition
E1
0 . . . N
Filtering
NA
condition
FilteringInput-
A
1
Selecting
Character string, optional selecting modes,
Style
mode of
for example, following arbitrary strings
the
may be included: “input by user”,
filtering
“selected by user in a pull down menu”,
parameter
“user can input or select in a pull down
menu”
FilteringParameterIdentifier
E2
Identifier
Character string
of filtering
parameter
FilteringParameterOperator
E2
1
Operator
Character string, optional operators
of filtering
between the filtering parameter identifiers
parameter
or values of the filtering parameters
selected by the user, which may be:
equals, not_equals, greater_than,
greater_than_or_equal, less_than,
less_than_or_equal. This parameter may
include a plurality of operators.
FilteringParameterEncoding
E2
0 . . . 1
Type of
Character string, which defines the
filtering
encoding mode of
parameter
FilteringParameterValue, the string
value
multimedia digital signal encoding
(StringCodec) may be employed, the
available types of filtering parameter value
is as follows: string, signed short, long,
boolean, float, double, date
FilteringParameterValue
E2
1
Optional
Character string, the filtering parameter
value of
values available for the user to select, the
filtering
encoding mode is determined by
parameter
FilteringParameterEncoding. There may
be arbitrary number of parameter values.
In the above table, E represents Element, A represents Attribute, E1 represents the first layer element, E2 represents the sub-element of the first layer element, and the rest may be deduced by analogy.
The server may send the filtering condition list to the terminal with the data structure RelatedMaterial in the existing ESG.
When the server sends the filtering condition list to the terminal with the data structure RelatedMaterial, two modes, i.e., Pull mode and Push mode, may be employed. The Pull mode is initiated by the terminal. The terminal obtains the address of the filtering condition list with the parameter MediaLocator of ESG, and submits application to the server. Then the server sends the filtering condition list to the terminal according to the application of the terminal. The Push mode is initiated by the server. The server puts the filtering condition list in the ESG and sends the ESG to the terminal via the broadcast network.
Specifically, the process of sending the structure of the description information to the terminal may be implemented in following three modes.
Mode I: The server performs configuration to make the parameter MediaLocator in the data structure RelatedMaterial include the filtering condition list, and then sends the data structure RelatedMaterial to the terminal. The terminal obtains the filtering condition list from the parameter MediaLocator in the received data structure RelatedMaterial directly, and stores the filtering condition list. The filtering condition list may be included in the parameter MediaLocator of the data structure RelatedMaterial of the service fragment, or may be included in the parameter MediaLocator of the data structure RelatedMaterial of the content fragment, or may be included in the parameter MediaLocator of respective data structure RelatedMaterial of the service fragment and content fragment simultaneously. This mode is referred to as the Push mode.
Mode II: The server performs configuration to make a file in the structure of Auxiliary Data of ESG include the filtering condition list, performs configuration to make the parameter MediaLocator in the data structure RelatedMaterial include Uniform Resource Identifier (URI) of the file, and then sends the data structure RelatedMaterial to the terminal. The terminal obtains the URI through the parameter MediaLocator of the received data structure RelatedMaterial, finds the file corresponding to the URI in the structure of Auxiliary Data according to the URI, and obtains the filtering condition list from the file. For example, as shown in FIG. 6 , the filtering condition list is configured in a file of the structure of Auxiliary Data of ESG by the server. The URI of this file is metadataURI=“urn:dvb:ipdc:esg:filter”. The parameter MediaLocator in the data structure RelatedMaterial sent to the terminal by the server includes a URI, this URI=“urn:dvb:ipdc:esg:filter”. When receiving the data structure RelatedMaterial, the terminal obtains the URI in the parameter MediaLocator, finds the corresponding file in the structure of Auxiliary Data according to the URI, obtains the filtering condition list from the file, and stores the filtering condition list. The URI may be included in the parameter MediaLocator of the data structure RelatedMaterial of the service fragment, or may be included in the parameter MediaLocator of the data structure RelatedMaterial of the content fragment, or may be included in the parameter MediaLocator of respective data structure RelatedMaterial of the service fragment and content fragment simultaneously. This mode is referred to as the Push mode.
Mode III: The server performs configuration to make a file in the server include the filtering condition list, performs configuration to make the parameter MediaLocator in the data structure RelatedMaterial include a Uniform Resource Locator (URL) of effective “http”, “ftp”, “rtsp” or “tftp” addresses of this file, such as http://www.kbs.co.kr/Filter.xml, and then sends the data structure RelatedMaterial to the terminal. The terminal obtains the URL through the parameter MediaLocator of the received data structure RelatedMaterial, and accesses the server. The terminal finds the file corresponding to the URL according to the URL, and requests the server to provide this file. The server sends the file to the terminal. Finally, the terminal obtains the filtering condition list from this file and stores the filtering condition list. The URL may be included in the parameter MediaLocator of the data structure RelatedMaterial of the service fragment, or may be included in the parameter MediaLocator of the data structure RelatedMaterial of the content fragment, or may be included in the parameter MediaLocator of respective data structure RelatedMaterial of the service fragment and content fragment simultaneously. This mode is referred to as the Push mode.
Hereinafter, the present invention is further illustrated by taking it as an example that the terminal determines whether the parameter in the received description information satisfies the stored filtering rules.
FIG. 7A shows a flow chart of configuring the filtering rules by the terminal according to an embodiment of the present invention. As shown in FIG. 7A , the specific implementing procedure of configuring the filtering rules by the terminal according to the filtering condition list from the server includes following steps:
Step 701 -Step 702 : The server configures a filtering condition list relevant to a specific notification service, and configures relevant information of the filtering condition list in ESG For example, the server performs configuration to make the parameter MediaLocator of the data structure RelatedMaterial of ESG include the filtering condition list, and then provides the data structure RelatedMaterial to the terminal. Alternatively, the server performs configuration to make a file in the structure of Auxiliary Data of ESG include the filtering condition list, and provide the URI of this file to the terminal. Alternatively, the server performs configuration to make a file in the server include the filtering condition list, and provides the URL of this file to the terminal.
Step 703 -Step 704 : The server sends relevant information of the filtering condition list to the terminal. The terminal obtains the filtering condition list according to the received relevant information of the filtering condition list. For example, when the server performs configuration to make the parameter MediaLocator of the data structure RelatedMaterial of ESG include the filtering condition list, the terminal obtains the filtering condition list in the parameter MediaLocator directly. Alternatively, when the server performs configuration to make the parameter MediaLocator of the data structure RelatedMaterial of ESG include the URI of the file of the filtering condition list, the terminal finds the file corresponding to the URI in the structure of Auxiliary Data according to the URI in the parameter MediaLocator, and obtains the filtering condition list from the file. Alternatively, when the server performs configuration to make the parameter MediaLocator of the data structure RelatedMaterial of ESG include the URL of the file of the filtering condition list, the terminal accesses the server according to the URL in the parameter MediaLocator, and requests the server to provide this file. The server obtains the filtering condition list from the file provided by the server.
Step 705 -Step 707 : The terminal analyzes the filtering condition list, prompts the terminal user to configure the filtering conditions and the relation between the filtering conditions according to the specific contents of the filtering condition list, generates the filtering rules, and stores the filtering rules.
FIG. 7B shows a flow chart of processing the notification message according to the filtering rules by the terminal according to an embodiment of the present invention. As shown in FIG. 7B , the specific implementing procedure of processing the notification according to the filtering rules by the terminal includes following steps:
Step 708 -Step 709 : The server needs to send a notification message to the terminal, the description information is added in the notification message, and then the notification message carrying the description information is sent to the terminal.
Step 710 -Step 711 : When receiving the notification message, the terminal obtains the parameters from the description information, and determines whether the parameters satisfy the stored filtering rules. If the parameters satisfy the stored filtering rules, the terminal displays the notification message to the terminal user; otherwise, the terminal discards this notification message directly. Thus, the notification message obtained by the terminal user is the most interesting notification message for the terminal user. When the parameters satisfy the filtering rules, the terminal may also store the notification message. If the description information satisfies a configured structure, obtaining the parameters from the description information by the terminal refers to determining the parameter value corresponding to the parameter identifier according to the configured structure. When the description information only includes the content of the description information, obtaining the parameters from the description information by the terminal refers to determining the parameter value corresponding to the parameter identifier according to the stored structure of the description information.
The terminal stores locally the filtering rules. The filtering rules may constitute a decision tree with respect to the data structure. As shown in FIG. 7C , the decision tree is constituted by a root node and individual sub nodes included by the root node. The top node is the root node, and the bottom nodes are leaf nodes. The root node includes a plurality of sub nodes, and the relation between each sub nodes from top to bottom is an iterative relation and/or inclusion relation. The leaf nodes refer to the nodes that have no sub nodes, and the non-leaf nodes refer to the nodes that have sub nodes. The data structure of the root node of filtering rules is as shown in Table 4.
TABLE 4
Schematic data structure of the root node of filtering rules
Parameter
Data Type
Node {
Node
JudgeValue
Boolean
FilteringConditionRelation
Integer
If(FilteringConditionRelation = null) {
}
else if(FilteringConditionRelation = operator “not”) {
SingleNode
Node
}
else if(FilteringConditionRelation=operator “or” or
“and”) {
DoubleNodeL
Node
DoubleNodeR
Node
}
}
In above table, JudgeValue is a judgment value. When the node is a leaf node, the judgment value of this node is determined according to whether the filtering condition of the node is satisfied. When the node is a non-leaf node, the judgment value of this node is determined through a calculation according to the filtering condition relation based on the judgment values of individual sub-nodes. FilteringConditionRelation is the filtering condition relation. SingleNode is a single sub-node, and when the filtering condition relation is the “not” operation, the SingleNode is a corresponding node of this operation. DoubleNodeL is a left sub-node. When the filtering condition relation is the “or” or “and” operation, the corresponding node is the sub-node on the left of the operator. DoubleNodeR is a right sub-node. When the filtering condition relation is the “or” or “and” operation, the corresponding node is the sub-node on the right of the operator.
In the data structure of the node, the data structure behind the filtering condition relation is determined by the value of the filtering condition relation: when the filtering condition relation is null, SingleNode, DoubleNodeL and DoubleNodeR do not exist; when the filtering condition relation is the “not” operation, only a parameter SingleNode exists, which indicates that only one sub-node is included; when the filtering condition relation is the “or” or “and” operation, only DoubleNodeL and DoubleNodeR exist.
The judgment value of the leaf node is determined by each filtering condition. When the parameter in the description information carried in the notification message satisfies the filtering condition, the judgment value of the leaf node is “true”, and when the parameter in the description information carried in the notification message does not satisfy the filtering condition, the judgment value of the leaf node is “false”. The judgment value of the non-leaf node is determined by a value obtained through a filtering condition relation calculation of the judgment values of the sub-nodes included in the non-leaf node. The judgment values of the leaf nodes are inserted into the decision tree, when the judgment value obtained through calculation of the judgment values of individual nodes according to the filtering condition relation is “true”, i.e., the judgment value of the root node is “true”, it is indicated that the parameters in the description information satisfy the filtering rule; when the judgment value obtained through calculation of the judgment values of individual nodes according to the filtering condition relation cannot be determined or is “false”, i.e., the judgment value of the root node cannot be determined or is “false”, it is indicated that the parameters in the description information do not satisfy the filtering rule. In other words, the judgment value of the leaf node is determined according to whether the filtering condition of the leaf node is satisfied. When the calculation of the judgment values of the leaf nodes according to the filtering condition relation is implemented, the judgment value of the non-leaf node where the leaf nodes are located is obtained. It is determined whether the non-leaf node is the root node. If the non-leaf node is not the root node, calculation is further implemented with respect to the judgment value of the non-leaf node according to the filtering condition relation, until the judgment value of the root node is obtained, and then it is determined whether the parameters satisfy the filtering rule according to the judgment value of the root node.
Hereinafter, the present invention is illustrated more explicitly by taking the filtering of the notification message of a film playing arrangement as an example.
A terminal user subscribes for a service relevant notification from the ESG, such as a notification of the latest film playing arrangement of a cinema. The server provides the terminal with relevant information of the filtering condition list, and the terminal obtains the filtering condition list, as shown in Table 5.
TABLE 5
Schematic contents of filtering condition list
Parameter
Data Type
FilteringConditionList {
FilteringConditionRelation
“not”, “or”, “and”
FilterCondition {
FilteringInputStyle
“terminal user selects in the
pull-down menu”
FilteringParameterIdentifier
“film type”
FilteringParameterOperator
“equal”, “not equal”
FilteringParameterEncoding
“character string”
FilteringParameterValue
“action film”, “disaster film”,
“comedy film”, “horror film”
}
FilterCondition {
FilteringInputStyle
“terminal user can input or select in the
pull-down menu”
FilteringParameterIdentifier
“actor name”
FilteringParameterOperator
“equal”, “not equal”
FilteringParameterEncoding
“character string”
FilteringParameterValue
“Jackie Chan”, “Jet Li”
}
FilterCondition {
FilteringInputStyle
“user input”
FilteringParameterIdentifier
“film introduction”
FilteringParameterOperator
“equal”, “not equal”
}
}
According to the specific contents in the filtering condition list, the terminal prompts the terminal user to select the filtering conditions and configure the relation among the filtering conditions. The filtering conditions that can be selected by the terminal user in the filtering condition list mainly include “film type”, “actor name” and “film introduction”. The terminal user is interested in the action film and disaster film, configures the “film type” twice in the filtering condition list, and sets the “film type” to be “action film” and “disaster film” respectively by performing selection in the pull-down list. Then the terminal user configures the relation between the filtering conditions. Because the terminal user is interested in both the action film and the disaster film, the filtering condition relation is set to be the operation “or”. Thus, the final filtering rule is displaying “a notification message whose film type is action film or whose film type is disaster film” to the terminal user. The decision tree generated by the filtering rules is as shown in FIG. 8A . The terminal stores the filtering rules. Thus, the judgment value of the leaf node 11 is determined according to whether the filtering condition is satisfied that “film type” is an action film, and the judgment value of the leaf node 12 is determined according to whether the filtering condition is satisfied that “film type” is a disaster film. The filtering rule condition of the root node is the operation “or”, the DoubleNodeL of the operation is the node 11 , and the DoubleNodeR of the operation is the node 12 . The judgment value of the root node is the judgment value obtained by performing an “or” operation with the judgment values of the node 11 and node 12 .
The server sends a notification message carrying the description information to the terminal. If the description information is structured description information, the description carried in the notification message is as shown in Table 6. If the structure of the description information is sent to the terminal by the server in advance, the content of the description information carried in the notification message is as shown in Table 7.
TABLE 6
Schematic structured description information
Parameter-
Parameter-
Parameter-
Parameter-
IdentifierLength
Identifier
Encoding
ValueLength
ParameterValue
8
Film type
Character
6
Action film
string
8
Actor name
Character
4
Jackie Chan
string
8
Film
Character string
100
This story happened
introduction
in . . .
TABLE 7
Schematic contents of the description information
ParameterIdentifier
ParameterValue
ParameterEncoding
Film type
Action film
Character string
Actor name
Jackie Chan
Character string
Film introduction
This story happened
Character string
in . . .
When receiving the notification message, the terminal extracts the parameters from the description information, and determines whether the parameters satisfy the filtering rules stored. Because the parameter value of the parameter identifier “film type” of the description information carried in the notification message is action film, the filtering condition of the leaf node 11 is satisfied, so the judgment value of the node 11 is true, and the filtering condition of the leaf node 12 is not satisfied, so the judgment value of the node 12 is false. The judgment value obtained by performing an “or” operation with the judgment values of the node 11 and node 12 is the judgment value of the root node. Finally, the judgment value of the root node is true, which indicates that the parameters in the description information satisfy the filtering rule, as shown in FIG. 8B . The terminal displays this notification message to the terminal user. The data structure of the node 11 is as shown in Table 8, the data structure of the node 12 is as shown in Table 9, and the data structure of the root node is as shown in Table 10.
TABLE 8
Schematic data structure of node 11
Parameter
Data value
Node {
JudgeValue
true
FilteringConditionRelation
null
}
TABLE 9
Schematic data structure of node 12
Parameter
Data value
Node {
JudgeValue
false
FilteringConditionRelation
null
}
TABLE 10
Schematic data structure of root node
Parameter
Data value
Node {
JudgeValue
true
FilteringConditionRelation
or
DoubleNodeL
Node 11
DoubleNodeR
Node 12
}
The terminal can not only implement filtering for the notification message according to the parameters in the description information and the filtering rules, but also perform other operations on the notification message according to the description information. For example, the terminal looks for a parameter in the description information. If the parameter can be found in the description information, the terminal processes the notification message, and if the parameter cannot be found in the description information, the notification message is discarded directly. Another example is that the terminal makes statistics on the number of times that the notification message appears, where configured parameter is included in the description information, i.e., when the description information includes the configured parameter, a counter is increased by 1, so as to make statistics on the number of times that the configured parameter appears in the notification message, etc.
In an embodiment of the present invention, the terminal that processes the notification message includes a receiving unit and a processing unit, as shown in FIG. 9A , where the receiving unit is adapted to provide the processing unit with the received notification message that carries description information, and the processing unit is adapted to process the received notification message according to the parameter included in the description information.
When the description information refers to the content of the description information, the terminal further includes a storing unit, where the receiving unit is further adapted to provide the storing unit with the received description information structure; the storing unit is adapted to store the description information structure and provide the processing unit with the description information structure; the processing unit is further adapted to process the content of the description information according to the description information structure, such as determine the parameter value corresponding to the parameter identifier in the description information structure. The receiving unit may further be adapted to provide the storing unit with the received description information structure.
The terminal further includes a storing unit, where the storing unit is adapted to store the filtering rule, and provide the processing unit with the filtering rule. The processing unit is further adapted to process the notification message, such as perform filtering, according to the filtering rule from the storing unit and the parameters in the description information.
On the basis that the receiving unit, processing unit and storing unit are included, the receiving unit is further adapted to provide the processing unit with the information of the received filtering condition list; the processing unit is further adapted to obtain the filtering condition list according to the information of the filtering condition list, analyze the filtering condition list, configure the filtering relation and the relationship between filtering conditions to generate the filtering rule, and provide the storing unit with the generated filtering rule.
In an embodiment of the present invention, a server that processes the notification message includes a message generating unit and a sending unit, as shown in FIG. 9B . The message generating unit is adapted to add the description information into the notification message, and provide the sending unit with the notification message. The sending unit is adapted to send the notification message carrying the description information. The server further includes a list generating unit, where the list generating unit is adapted to generate the filtering condition list, and provide the sending unit with the information of the filtering condition list. The sending unit is further adapted to send the information of the filtering condition list. When the description information refers to the content of the description information, the server further includes a structure generating unit, where the structure generating unit is adapted to determine the structure of the description information and provide the sending unit with the structure. The sending unit is further adapted to send the structure of the description information.
In an embodiment of the present invention, the system that processes the notification message includes a server and a terminal, as shown in FIG. 9C , where the server is adapted to add the description information into the notification message, and send the notification message to the terminal. The terminal is adapted to process the received notification message according to the parameter included in the description information. When the description information refers to the content of the description information, the server is further adapted to determine the structure of the description information and send the structure to the terminal. The terminal is further adapted to store the structure of the description information, and determine the parameter according to the structure of the description information and the content of the description information when the notification message is received. The terminal is further adapted to store the filtering rule, and process the received notification message according to the filtering rule and the parameter included in the description information. The server is further adapted to generate a filtering condition list, and send information of the filtering condition list to the terminal. The terminal is further adapted to obtain the filtering condition list according to the information of the filtering condition list, analyze the filtering condition list, and prompt the terminal user to configure the filtering conditions and the relationship between the filtering conditions, so as to generate the filtering rule.
The terminal includes a receiving unit and a processing unit. The receiving unit is adapted to provide the processing unit with the received notification message that carries the description information, and the processing unit is adapted to process the received notification message according to the parameter included in the description information. When the description information refers to the content of the description information, the terminal further includes a storing unit, where the storing unit is adapted to store the structure of the description information, and provide the processing unit with the structure of the description information. The processing is further adapted to process the content of the description information according to the structure of the description information, such as determine the parameter value corresponding to a parameter value in the structure of the description information. The terminal further includes a storing unit, where the storing unit is adapted to store the filtering rule, and provide the processing unit with the filtering rule. The processing unit is further adapted to process the notification message according to the parameter included in the description information and the filtering rules from the storing unit. On the basis that the receiving unit, processing unit and storing unit are included, the receiving unit is further adapted to provide the processing unit with the information of the received filtering condition list; the processing unit is further adapted to obtain the filtering condition list according to the information of the filtering condition list, analyze the filtering condition list, configure the filtering relation and the relationship between filtering conditions to generate the filtering rule, and provide the storing unit with the generated filtering rule.
The server includes a message generating unit and a sending unit. The message generating unit is adapted to add the description information into the notification message, and provide the sending unit with the notification message. The sending unit is adapted to send the notification message carrying the description information. The server further includes a list generating unit, where the list generating unit is adapted to generate the filtering condition list, and provide the sending unit with the information of the filtering condition list. The sending unit is further adapted to send the information of the filtering condition list. When the description information refers to the content of the description information, the server further includes a structure generating unit, where the structure generating unit is adapted to determine the structure of the description information and provide the sending unit with the structure. The sending unit is further adapted to send the structure of the description information.
It is obvious that various modifications and variations will occur to those skilled in the art without departing from the spirit and scope of the present invention. Therefore, when such modifications and variations of the present invention fall within the scope of the claims of the present invention and the equivalent technology, they are intended to be included by the present invention.
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A method, terminal, server and system for processing the notification message are disclosed. According to the method, the server transmits the notifying message with description information. The description information contains the parameter; the terminal parses the notifying message after receiving the notifying message. The description message may contain one or more parameter, thereby providing more messages through the notifying message to the terminal, making the terminal user getting the wanted information quickly. After the description message is added to the notifying message, the terminal can perform a variety of processes on the received notifying message.
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FIELD OF THE INVENTION
The present invention relates to a connector assembly for tubular members and more particularly to an improved connector assembly for tubular members used as decorative elements for mounting on beds of open backed trucks.
DESCRIPTION OF THE PRIOR ART
It is not uncommon for owners of open backed vehicles such as open back trucks to install tubular decorative bars, for example, on the bed of the truck and to the rear of the passenger cab. Typically one or more decorative tubular elements are bolted to the open backed bed of the truck, extend above the truck bed to about the height of the cab and extend transversely across the bed of the truck from one side edge of the truck bed to the other. Normally such decorative bar assemblies also include spaced tubular bars which are mounted on the transverse bar(s) and extend axially along the back and along each side of the truck.
One end of the axially extending tubular member is affixed at an angle to the transverse bar and slopes downwardly from the transverse bar towards the rear of the truck bed and the other end is normally bolted to the truck bed. It is not unusual to mount lights or other items on the transverse portion of the decorative bar structure. The decorative bars are generally tubular in cross-section and normally are chromed for attractive appearance.
It is also the case that these decorative bar assemblies are fabricated into sets, a kit so-called, depending upon the type of truck and are most frequently installed by the user. While the kits are intended to fit the various types and styles of trucks, sometimes due to manufacturing or condition of the truck itself, the axially extending side tube sections do not mount properly to the transverse section or to the floor or bed of the truck.
While these tubular members are not structural roll-over bars, they are of such a structure that they are not easily bent, as may be needed if there are installation problems. Since the principal function of these decorative roll-over bars is enhancement of the appearance of the vehicle, improperly fitting parts tend to distract from the very purpose for which they are most often used, i.e., to enhance the attractiveness of the vehicle itself.
Heretofore, it was known to provide the transverse tubular member with pre-drilled holes in the region where the transverse and axially extending bars were to be joined. A threaded bolt passed through the transverse bar and was used to bolt the axial bar in place. One end of the axial bar was provided with a foot with pre-drilled holes for mounting on the bed of the truck. The other end of the axial bar, i.e., the end which mounts to the transverse bar, was contoured so that it fit with the contour of the transverse bar, the orientation being such that the axial bar is at an angle, normally a right angle plane, with respect to the transverse bar. The contouring essentially involved shaping the end of the axial bar such that it mated with the opposing curved surface of the transverse bar.
On the interior of the shaped hollow end of the axially extending tubular element, a flat planar cross-piece was affixed, as by welding to the interior of the axially extending tubular element such that the latter extended across the diameter of the open end of the axial member, but recessed sufficiently to allow the axial member to fit snugly against the transverse member. This planar cross-piece was provided with a nut which mated with the bolt. The location of the nut was fixed so that the installation involved aligning the axial member to the region of the transverse member through which the bolt passed and then tilting the contoured end of the axial member until the threaded end of the bolt could be threaded into the nut.
Since the orientation of the bolt is fixed, depending on the angle of the bolt as controlled by the line of sight bolt openings in the transverse member, proper alignment and installation also required that the nut be properly oriented to mate with the bolt. Like the bolt, the orientation of the nut was also fixed. If there was a mismatch, it became difficult to assemble the axial member to the transverse member.
If there was a mismatch, it was necessary to move the mounting end of the axial member through an arc until mating was achieved. To move the axial member through an arc, typically the entire axial member was rotated, i.e., the other end of axial member or that which bolted to the bed of the truck had to be lowered or raised. If matching required a lifting of the end of the axial member, there was no major problem. However, if matching required lowering the end of the axial member, the truck bed created interference which limited the downward movement of the end of the axial member to achieve a match to permit the connection to be made.
A mismatch could arise for several reasons including unevenness of the truck bed or simply non-matching due to manufacturing problems such as worn or misaligned tooling.
Thus, there is a need for an improved connection assembly which allows the axially aligned tubular member to be adjustably and arcuately rotated about the transverse tubular member to achieve the required rotational or arcuate angle, according to the fixation points, just prior to securing the connection of the two tubular members.
It is thus an object of this invention to provide an improved and relatively simple connecting assembly for transverse and axial tubular members such that there is ample adjustment available in either direction of the axial member in order to achieve assembly thereof to the transverse member.
Another object of this invention is to provide a relatively simple structure for quick and easy connection of a tubular member to a transverse tubular member such that the arcuate angle of the axial member about the transverse member may be easily adjusted so as to allow proper assembly of the two members while permitting the end of the axial member to be securely fixed to a support structure.
Still another object of this invention is to provide a decorative bar structure for mounting on the bed of a vehicle, such as an open bed truck, and which includes at least one transverse tubular member and at least one axially extending tubular member wherein an improved interconnection assembly is provided to assure some adjustment of the axial member with respect to the transverse member in order to compensate for misalignment of the parts to be interconnected.
Still another object of this invention is to provide an improved connecting assembly whose manufactured parts are not significantly more complicated or costly than existing connecting assemblies.
SUMMARY OF THE INVENTION
These and other objects of the present invention are achieved through the use of a tubular transverse member which is preferably pre-drilled to provide an opening through which a threaded fastener extends at a predetermined angle. At least one tubular axially extending member is provided which includes one end having a contour which basically matches that of the transverse member at the mounting region and another end which is adapted to be mounted on the support surface, typically the bed of the open backed vehicle. Typically, there are two spaced axial members mounted in spaced relation to each other along the side of the vehicle.
To permit arcuate adjustment of the axial members relative to the transverse member, the contoured end of the axial member is provided with a carrier which is fixed to the interior thereof, the latter being generally arcuate, and which supports a movable carrier. The carrier, in turn supports a threaded member which mates with the threaded member on the transverse tubular element. In this way, the axial member may be arcuately adjusted relative to the transverse member so that the threaded members mate and the other end of the axial member may be fixed to its support structure. If arcuate movement is needed, it is provided for by the arcuately movable threaded member carried by the carrier. Once adjusted and fixed to the support, the other end of the axial member may be securely fastened to the transverse member.
Thus, the improved connector assembly in accordance with this invention is relatively simple to manufacture and relatively simple to install which providing the advantage of compensating for any mismatch of the types described.
DETAILED DESCRIPTION OF THE DRAWINGS
FIG. 1 is a view in perspective illustrating a typical tubular assembly in accordance with the present invention, in the form of a decorative bar for a vehicle;
FIG. 2 is a developed view of the tubular assembly in accordance with this invention;
FIG. 3 is a view, partly in section and partly in elevation, of the tubular assembly in accordance with this invention;
FIG. 4 is view in perspective of the carrier and threaded element in accordance with this invention; and
FIG. 5 is a side view of the carrier and threaded element in accordance with this invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to the drawings which illustrate a preferred form of the present invention, FIG. 1 is a diagrammatic view of the tubular assembly 10 in accordance with this invention. As illustrated, the tubular assembly 10 includes at least one transversely positioned tubular element 12, the latter located to the rear of the passenger section 14 of the vehicle 15. The transverse element is mounted on the bed 17 of the rear of the truck and extends from one side to the other of the truck bed. It is recognized that the configuration of the transverse member may be any one of several possible configurations and that the member shown is for purposes of illustration. Further, the tubular assembly is illustrated as mounted on a vehicle body for purposes of illustration only.
As shown, the legs 20, 21 of the transverse member are also tubular and are bolted or otherwise affixed to the bed 17. The transverse member 12 may carry lights or other items 24 and the height of the transverse element 12 is such that it is about equal to the top of the passenger section 14. It is understood that the tubular assembly is a decorative unit and is not intended to be a structural roll-over bar assembly.
Cooperating with the transverse tubular element 12 are a pair of spaced axially oriented elements 25 and 30. The term axial is intended to be a relative orientation with respect to a vehicle axis, again for purposes of illustration. Each of the axial tubular elements is of essentially the same general configuration and includes one end 25a and 30a which is affixed to the transverse element 12 and another end 25b and 30b (not visible) which is affixed to the bed.
The transverse member 12 and the axial members 25 and 30 usually come in a kit form dimensioned for each type of vehicle size and of different decorative combinations and are assembled to the support structure, in this case an open bed truck, by the user. Typically, the tubular elements are tubular steel elements, which may be chrome or painted finished, and of a generally circular cross-section. Other cross-sectional shapes may be used and generally include a curved or arcuate surface portion at the connection between the axial and transverse members. As shown, the plane of the axial members is in a perpendicular relation with the plane of the transverse member.
For example, as seen in FIGS. 2 and 3, the interconnection between the axial members 25 and 30 and the transverse member 12 is basically the same. The transverse member includes pre-drilled apertures 35 in a predetermined orientation depending on the factory set angular connection with the axial member, 25, for purposes of explanation. The portion of the surface between the apertures generally includes a curved surface portion 37, as shown. Received in the apertures 35 is a threaded fastener 40, in the form of a bolt, the latter having a length sufficient to extend some distance through element 12, as will be described.
The end 25a of the member 25 is configured to follow and mate with the contour of the surface portion 37, as shown. The result is that two spaced ears 41 and 42 are formed. The end 25a of member 25 includes a carrier 45 which is arcuate in shape, see also FIG. 5, the arc following generally the arc of the curved surface portion 37. The carrier also is slotted as at 47, but not slotted all the length, for ease of mounting in the tubular element 25. Mounted on the carrier 45 is a slidable fastener element 50 which ultimately mates with threaded fastener 40 to join the two parts together securely.
In a preferred form, the slidable fastener includes a locator hole 51 on one side and which is not threaded and which is of a diameter slightly larger than the diameter of the fastener 40. On the side opposite the locator hole 51 and in alignment therewith and carried on the carrier is a threaded member 53 which mates with member 40. The slidable fastener includes side walls 56 and 57 through which the carrier passes so that there is a guiding movement.
As seen in FIGS. 2 and 3, the carrier is fixed to the interior of the tubular element 25 at end 25a and recessed back from the open end thereof. In effect, each leg 45a and 45b is aligned with an ear 41 and 42. The carrier is oriented such that the locator hole 51 faces toward the open end, i.e., towards the transverse member, while the threaded member is facing the interior of the member 25, i.e., away from the transverse member. In assembly, the slidable fastener 50 is slipped over the carrier, correctly oriented as described and the carrier is then affixed to the interior of the end 25a of the tubular element as by welding and the like. Since the carrier is slightly spaced from the open end and the legs thereof are aligned with the ears, this is a relatively simple assembly and manufacturing operation.
In assembling the transverse and axial members together, the transverse member 12 is first mounted to the support structure. Thereafter, one of the axial member 25 or 30 is mounted on the transverse member by locating the end of threaded member 40 in the locator hole 51 and threading enough of that member into the slidable member 50 to mate with the threads on threaded element 53. The other end of the axial member is then assembled to the support structure. This is followed by tightening fastener 40. If the alignment is ideal in the sense that the end 25b or 30b of the axial members are properly positioned on the support structure, then the slidable threaded element 50 should be located at about the mid-point of the carrier.
The advantage of this invention now becomes clear in that instance in which the alignment is not ideal, i.e., the end 25b or 30b of the axial member is not properly seated on the support structure. If there is improper seating, the axial member may be moved arcuately relative to the transverse member to achieve proper seating. This is possible in accordance with this invention since the slidable fastener 50 is movable along the carrier, from one interior wall portion to the other of the interior of the axial member. The position of threaded fastener 40 is fixed by the orientation of the apertures 35, thus, it is not free to move arcuately.
The outer tubular element 25 or 30, however, is arcuately movable relative to the fastener 40 by virtue of the effectively arcuate movement of the slidable fastener element 50 on the arcuate carrier 45. This arcuate movement is illustrated in the phantom lines in FIG. 3. It is for this reason that the length of the fastener 40 should be sufficient to engage the threaded portion 53 of the slidable carrier 45 and why the slidable carrier is of an arcuate configuration generally following the contour of the transverse element. The effect is adjustment in an arcuate manner on each side of a center line which is the center axis of the threaded element 40. Such adjustment is sufficient to permit proper installation and to compensate for irregularity of the support surface or misalignment due to manufacturing or both.
It is apparent from the foregoing detailed description that an improved connector assembly is provided. It will also be apparent that various modifications thereof may be made without departing from the invention as set forth in the appended claims.
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Apparatus for connecting two tubes in a T-shape which permits the tube which is extended perpendicular from the middle of the other tube to be adjusted to a certain degree about the circumference of the other tube before the tubes are secured to one another.
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RELATED APPLICATION DATA
This application claims benefit under 35 U.S.C. Section 119(e) of U.S. Provisional Applications 60/901,426 and 60/901,509, both filed Feb. 13, 2007, both of which are incorporated by reference in their entirety.
BACKGROUND
The present invention relates to a window assembly for a door of a construction vehicle. More specifically, the present invention relates to a window assembly that inhibits breakage of the window due to impact or vibrations caused by operation of the vehicle, but allows an operator to escape the vehicle in case of emergency.
SUMMARY
In one embodiment, the invention provides a door assembly for a construction vehicle. The door assembly includes a frame member that has an inside surface and an outside surface and is releasably coupled to the vehicle. A window pane is positioned proximate one of the inside surface and outside surface. A first resilient member is positioned between the frame member and the window pane, to substantially vibrationally isolate the frame member and the window pane. A fastener extends through the frame member, window pane and first resilient member to couple the window pane to the frame member. A second resilient member is positioned between the window pane and the fastener to substantially vibrationally isolate the window pane and the fastener. A pair of hinges are coupled to the frame member and a pair of hinge pins selectively extend into the respective one of the pair of hinges. A lever is coupled to the pair of hinge pins for moving the pair of hinge pins relative to the pair of hinges upon movement of the lever, to selectively detach the door assembly from the vehicle.
In another embodiment, the invention provides a door assembly having a frame member that defines a window aperture and a frame hole. A gasket is constructed of a resilient material and is adjacent the frame member and substantially surrounds the window aperture. The gasket defines a gasket hole substantially aligned with the frame hole. A windowpane is positioned adjacent the gasket and the windowpane substantially covers the window aperture and defines a window hole substantially aligned with the gasket hole. A washer constructed of a resilient material is adjacent the windowpane. The washer defines a washer hole substantially aligned with the window hole. At least one fastener assembly extends through the substantially aligned frame hole, gasket hole, window hole, and washer hole, and has a first end that defines a first enlarged portion that abuts against the frame member, and a second end opposite the first end. The second end defines a second enlarged portion, and abuts against the washer. A lever is coupled to the frame member, and at least one hinge pin is coupled to the lever for movement in response to movement of the lever.
In another embodiment, the invention provides a method of opening a door of a construction vehicle. The door includes at least one resilient member positioned between a frame member and a window pane, and the door is rotatable with respect to the vehicle about at least one hinge. The method includes rotating a lever positioned on the inside of the vehicle, removing at least one hinge pin from the at least one hinge, pushing the door open, and detaching the door from the vehicle.
In some embodiments, a plurality of fastener assemblies support the windowpane in the absence of a rigid structural element, such as an external frame positioned between the windowpane and the plurality of fastener assemblies.
In other embodiments, the second enlarged portions of the fastener assemblies abut directly against the resilient washers.
In some embodiments, the window holes define counter bore portions extending from the outer surface and the resilient washers are positioned within the counter bores. The second enlarged portions of the fastener assemblies are at least partially disposed within the counter bores.
In some embodiments a stack height of the fastener assembly equals the sum of the thickness of the gasket, distance from the inner surface of the windowpane to the resilient washer, and thickness of the resilient washer. Each fastener assembly includes a shoulder having a diameter larger than the diameter of the frame holes, such that the shoulder abuts against the frame member around the frame hole. Abutment of the shoulder against the frame member fixes the distance between the second enlarged portion and the frame member to be slightly smaller than the stack height of the fastener assembly to slightly preload the gasket and resilient washer.
Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side view of a skid steer loader according to one embodiment of the present invention.
FIG. 2 is a perspective view of the skid steer loader of FIG. 1 .
FIG. 3 is an exploded view of a door assembly of the skid steer loader of FIG. 1 .
FIG. 4 is a cross-sectional view of a portion of the door assembly of FIG. 1 , taken along line 4 - 4 of FIG. 2 .
FIG. 4A is a close-up section view of a portion of the door assembly of FIG. 1 , taken from FIG. 4 .
FIG. 5 is a front view of the door assembly in a locked position from inside the skid steer loader of FIG. 1
FIG. 6 is a front view of the door assembly from outside the skid steer loader of FIG. 1 .
FIG. 7 is a front view of the door assembly in an unlocked position from inside the skid steer loader of FIG. 1 .
FIG. 8 is a partial side view of the door assembly of FIG. 7 .
DETAILED DESCRIPTION
Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms “mounted,” “connected,” “supported,” and “coupled” and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings.
FIGS. 1 and 2 depict a skid steer loader 10 having a frame member 15 supported by two right side wheels 20 and two left side wheels 25 , an internal combustion engine 30 , an operator compartment 35 that contains an operator control 37 , right and left lift arms 40 , and a bucket 45 mounted for tilting between the distal ends of the lift arms 40 . Although the invention is illustrated embodied in a skid steer loader 10 , the invention may be embodied in other construction vehicles and machines, including for example, excavators, track loaders, skid steer loaders, front end loaders, utility vehicles and other similar vehicles and machines. Although the illustrated operator control 37 takes the form of a joystick, in other embodiments, the operator control 37 may include multiple joysticks, foot pedals, and/or steering wheels.
The right side wheels 20 are driven independently of the left side wheels 25 . When all four wheels 20 , 25 rotate at the same speed, the loader 10 moves forward and backward, depending on the direction of rotation of the wheels 20 , 25 . The loader 10 turns by rotating the right and left side wheels 20 , 25 in the same direction but at different rates, or turns about a substantially zero turn radius by rotating the right and left side wheels 20 , 25 in opposite directions.
The lift arms 40 raise (i.e., rotate counterclockwise in FIG. 1 ) and lower (i.e., rotate clockwise in FIG. 1 ) with respect to the frame member 15 under the influence of lift cylinders 50 mounted between the frame member 15 and the lift arms 40 . The bucket 45 tilts with respect to the arms 40 to curl (i.e., rotate counterclockwise in FIG. 1 ) and dump (i.e., rotate clockwise in FIG. 1 ) under the influence of tilt cylinders 55 mounted between the lift arms 40 and the bucket 45 . Various auxiliary implements or devices may be substituted for or used in conjunction with the bucket 45 . An exemplary, but by no means exhaustive, list of auxiliary implements includes augers, jack hammers, trenchers, grapples, rotary sweepers, stump grinders, saws, concrete mixers, pumps, chippers, snow throwers, rotary cutters, and backhoes.
FIG. 3 depicts an exploded view of a door assembly 200 for accessing the operator compartment 35 . The door assembly 200 includes a door frame 210 , a gasket 220 , a windowpane 230 , and a plurality of fasteners 240 , nuts 250 , and resilient washers 260 . The door frame 210 defines a window aperture 270 and includes both inside and outside surfaces 280 , 290 . The door frame 210 is made of steel or any other suitably rigid material. The door frame 210 includes a plurality of frame apertures 300 around a perimeter of the window aperture 270 . The gasket 220 substantially follows the shape of the window aperture 270 and is abutted against the outside surface 290 of the door frame 210 . In this regard, the outside surface 290 of the door frame 210 may be termed a bearing surface. The gasket 220 is made of resilient, shock absorbing material and includes a plurality of gasket apertures 310 . The windowpane 230 substantially follows the shape of the window aperture 270 and is made from a sheet of LEXAN® or other suitable see-through material. In this regard, the windowpane 230 may be transparent, translucent, tinted, or otherwise customized for the desired application. The windowpane 230 has inside and outside surfaces 313 , 317 . The windowpane 230 substantially covers at least a portion of the window aperture 270 , and at least a portion of the inside surface 313 of the windowpane 230 abuts against the gasket 220 . Located around a perimeter of the windowpane 230 are a plurality of window holes 320 . The fasteners 240 are shoulder bolts in the illustrated embodiment. The nuts 250 are threaded to mate with the fasteners 240 . The resilient washers 260 are made of resilient, shock absorbing material.
FIG. 4 is a cross-sectional view of a fastener assembly 400 used in the door assembly 200 . Each fastener assembly 400 includes: one fastener 240 , one resilient washer 260 , and one nut 250 to secure the windowpane 230 and gasket 220 to the door frame 210 . The frame holes 300 , gasket holes 310 , and window holes 320 are substantially aligned to allow for the passage of the fastener 240 therethrough. The window hole 320 has a through bore 410 extending from the inside surface 313 and a larger diameter counter bore 420 extending from the outside surface 317 and communicating with the through bore 410 . The fastener 240 has a threaded end 430 , a head 440 , and a shoulder 450 between the threaded end 430 and head 440 . The head 440 has a larger diameter than the shoulder 450 , and the shoulder 450 has a larger diameter than the threaded end 430 . The length of the shoulder 450 on the fastener 240 is slightly less than the combined uncompressed stack height of the resilient washer 260 , the length of the through bore portion 410 of the window hole 320 , and the gasket 220 , to allow for slight compression or preloading of the resilient gasket 220 and washer 260 upon assembly.
As shown in FIG. 4 , the threaded end 430 of the fastener 240 passes through the frame hole 300 . The nut 250 is threaded onto the threaded end 430 of the fastener 240 and tightened so the nut 250 rests on the inside surface 280 of the door frame 210 and the end of the shoulder 450 rests against the outside surface 290 of the door frame 210 . The head 440 and nut 250 may be termed enlarged portions of the fastener assembly 400 . The fastener assembly 400 can be inverted such that the head 440 is against the door frame 210 and the nut 250 is against the resilient washer 260 . If the fastener assembly 400 is inverted, a combination of a standard bolt and a sleeve having outer dimensions similar to that of the shoulder 450 of the fastener 240 may be used in place of the fastener 240 .
FIG. 4A shows the resilient washer 260 having an inner and outer diameter 460 , 470 . The resilient washer 260 separates the head 440 from the bottom of the counter bore portion 420 of the window hole 320 . The outer diameter 460 of the resilient washer 260 is slightly smaller than the diameter of the window hole counter bore 420 . The inner diameter 460 of the resilient washer 260 is slightly larger than the diameter of the shoulder 450 , and smaller than the diameter of the head 440 . In this regard, the inner diameter 460 of the resilient washer 260 may be termed a washer hole. When seated, the head 440 of the fastener 240 rests upon the resilient washer 260 and is partially recessed with respect to the outer surface 317 of the windowpane 230 in the window hole counter bore 420 . The shoulder 450 of the fastener 240 passes through the inner diameter 460 of the resilient washer 260 , through the through bore 410 , and through the gasket hole 310 .
The windowpane 230 can move along the axis of the fastener 240 upon impact. The gasket 220 and the resilient washer 260 absorb forces causing deflection of the windowpane 230 upon impact. The gasket 220 and the resilient washer 260 also substantially vibrationally isolate the windowpane 230 from the frame member 210 . Further, the fastener 240 resists movement of the windowpane 230 in directions parallel to the fastener axis.
FIGS. 5 and 6 show the door assembly 200 including the door frame 210 and the windowpane 230 with the door assembly 200 in a locked position. FIG. 5 is the view from inside the operator compartment 35 , whereas FIG. 6 is the view from outside of the operator compartment 35 . The door assembly 200 further includes first and second hinges 500 , 510 , respectively, coupled to the door frame 210 . First and second hinge pins 520 , 530 , respectively are coupled to the loader 10 and are inserted into the respective first and second hinges 500 , 510 in the illustrated configuration. The hinge pins 520 , 530 are rotatable within the hinges 500 , 510 to allow the door assembly 200 to rotate with respect to the loader 10 .
The door assembly 200 further includes a latching mechanism 550 on the opposite side of the door assembly 200 as the hinges 500 , 510 and hinge pins 520 , 530 . When an operator desires to enter or exit the loader 10 , the latching mechanism 550 can be actuated to allow the door assembly 200 to pivot at the hinges 500 , 510 about hinge pins 520 , 530 .
In some circumstances, the door assembly 200 cannot pivot about the hinges 500 , 510 and hinge pins 520 , 530 due to lack of space, an object in the way of the door path or various other reasons. Also, in some emergency cases, it may be desirable to detach the door assembly 200 from the loader 10 to allow for quick egress from the operator compartment 35 .
A lever 560 is provided on the interior of the operator compartment 35 for rotation relative to the door frame 210 . The lever 560 is coupled to a cam member 570 for rotation with the cam member 570 . The hinge pins 520 , 530 are coupled to the cam member 570 for substantially linear movement into and out of the hinges 500 , 510 , in response to rotation of the lever 560 and cam member 570 . The illustrated hinge pins 520 , 530 and the cam member 570 are positioned on the exterior of the loader 10 . Rotation of the lever 560 causes the door assembly 200 to detach from the loader 10 , and thereby allow for egress from the loader 10 when the door assembly 200 cannot pivot about the hinges 500 , 510 .
FIGS. 7 and 8 show the door assembly 200 with the lever 560 and cam member 570 pivoted along arrow A to an open position so that the hinge pins 520 , 530 are withdrawn from hinges 500 , 510 . Therefore, the door assembly 200 can be detached from the loader 10 allowing quick egress of an operator, even if the door assembly 200 is blocked from pivoting about the hinges 500 , 510 . With the hinge pins 520 , 530 withdrawn from the hinges 500 , 510 , the door assembly 210 is no longer coupled to the loader 10 . Both of the hinges pins 520 , 530 are simultaneously withdrawn from the respective hinges 500 , 510 when the lever 560 is rotated about arrow A.
In the illustrated embodiment, the hinge pins 520 , 530 are inserted into sleeves 580 , 590 on the door assembly 200 prior to insertion into the hinges 500 , 510 on the loader 10 . Therefore, the hinge pins 520 , 530 only need to be withdrawn from the hinges 500 , 510 on the loader 10 and need not be withdrawn from the sleeves 580 , 590 on the door assembly 200 as well. In other non-illustrated embodiments, no sleeves are utilized, so that the hinge pins 520 , 530 are received into the respective hinges 500 , 510 directly. In another embodiment, the hinges 500 , 510 are positioned on the door assembly 200 and the hinge pins 520 , 530 and sleeves 580 , 590 are coupled to the loader 10 .
The door assembly 200 is easily re-mounted to the loader 10 after being detached. In order to re-attach the door assembly 200 to the loader 10 , the door assembly 200 is held in abutment with the loader 10 such that the hinge pins 520 , 530 are adjacent the hinges 500 , 510 . The lever 560 is pivoted to insert the hinge pins 520 , 530 into the respective hinges 500 , 510 .
The substantially linear movement of the hinge pins 520 , 530 is shown more clearly in FIGS. 7 and 8 as being substantially vertical, but in another embodiment, depending on the orientation of the hinges, the movement is substantially horizontal, whereas in yet another embodiment, the movement is substantially diagonal, and in yet another embodiment, the hinge pin 520 , 530 movement is substantially skew. Further, the cam member 570 is illustrated as being diamond-shaped, but other shapes, such as ovals, circles, rectangles, squares and so on are possible and are considered to be within the scope of the present invention.
Thus, the invention provides, among other things, a more secure method of mounting an impact resistant window to the door frame of a utility work vehicle than has been previously employed. The plurality of fastener assemblies 400 resist movement of the windowpane 230 in directions perpendicular to the longitudinal axes of the fastener assemblies 400 . The resilient gasket 220 and resilient washers 260 substantially absorb forces causing deflection of the windowpane 230 in directions parallel to the longitudinal axes of the fastener assemblies 400 . The fastener assemblies 400 support the windowpane in the absence of a rigid structural element, such as an external frame, extending along the outer surface 317 of the windowpane 230 between the plurality of fastener assemblies 400 . The invention further provides a door assembly 200 with a lever 560 for detaching the door assembly 200 from the loader 10 to allow for egress from the loader 10 in case of emergency. Various features and advantages of the invention are set forth in the following claims.
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A construction vehicle door assembly includes a frame member having an inside surface and an outside surface, a window pane is positioned proximate one of the inside surface and outside surface, and a first resilient member substantially vibrationally isolates the frame member and the window pane. A fastener extends through the frame member, window pane and first resilient member to couple the window pane to the frame member. A second resilient member substantially vibrationally isolates the window pane and the fastener. A pair of hinges are coupled to the frame member, a pair of hinge pins are selectively extended into the respective one of the pair of hinges, and a lever is coupled to the pair of hinge pins for moving the pair of hinge pins relative to the pair on hinges upon movement of the lever, to detach the door assembly from the vehicle.
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application is the National Stage of International Application No. PCT/NL2008/050101, filed Feb. 21, 2008, the contents of which is incorporated by reference herein.
FIELD OF THE INVENTION
The present invention relates to a laser catheter for bypass surgery, wherein the distal part of the catheter is provided with:
a tubular arrangement of optical fibres having distal ends defining a ring-shaped light emergence surface for emitting a tubular bundle of light beams in the distal direction of the catheter, a stop surface extending around the tubular arrangement of optical fibres and facing in the distal direction, the stop surface being arranged at a distance proximally from the light emergence surface.
BACKGROUND OF THE INVENTION
Such a laser catheter for bypass surgery is known from EP 750,476. This document describes the use in the ELANA (Excimer Laser Assisted Non-occlusive Anastomosis) operating technique. This Elana technique was developed by neurosurgeon C. A. F. Tulleken. For the Elana technique, one requires an Elana catheter and an Elana ring, which are jointly called Elana Arteriotomy System.
The catheter disclosed in EP 750,476 is used for performing an ETS-anastomosis (ETS=End To Side) between a graft vessel and a target vessel. The graft is fixed with an end to the side of the target vessel, while the blood flow through the target vessel, also called recipient vessel, is not interrupted, i.e. blood continues to flow through the target vessel while performing the anastomosis. For this purpose, first the graft vessel is fixed to the target vessel and subsequently, after this fixation is established, the flow connection between the target vessel and graft vessel is made by removing the part of the wall of the target vessel which lies in front of the fixed end of the graft vessel. Said part of the wall of the target vessel is removed by means of an tubular arrangement of optical fibres emitting a tubular bundle of laser light beams originating from the fibres and a suction gripper provided inside the tubular arrangement of optical fibres. The tubular bundle of laser light beams burns a circle into the wall of the target vessel, resulting in a circular passage connecting the lumens of the graft vessel and target vessel. The circular wall part of the target vessel—i.e. the part lying inside said burned circle—is gripped by the suction gripper and removed together with the withdrawal of the catheter after the burning operation. The distal ends of the optical fibres of this known laser catheter define a circle extending in a plane essentially perpendicular to the longitudinal axis of the catheter. During use the laser catheter extends perpendicular to the target vessel, resulting in a perpendicular ETS-anastomosis with a circular passage between the graft vessel and target vessel. In order to ensure a complete cutting away of tissue along the said circle, the teaching is that the cutting laser light beams should impinge on the target vessel as perpendicular as possible. This in order to avoid scattering of the laser light beams by inter alia reflection effects, which would maker the cutting action less effective and less reliable. A perpendicular impinging from the laser light beams further keeps the required depth of tissue to be burned away as short as possible. For example, in case the laser beams impinge at about 45° on the wall of the target vessel, the depth of tissue to be burned away is about 40% more than in case the laser beams impinge perpendicular.
There are however also applications, for example in the field of cardiovascular surgery but also in the field of surgery of intracranial arteries, in which a slanting ETS-anastomosis is desired or required. In a slanting ETS-anastomosis define the graft vessel and target vessel an angle different from 90°, in general in the range of 30°-60°.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a laser catheter for bypass surgery, which is suitable for use in a slanting ETS-anastomosis procedure.
According to the invention this object is achieved by providing a laser catheter for bypass surgery, wherein the distal part of the catheter is provided with:
a tubular arrangement of optical fibres having distal ends defining a ring-shaped light emergence surface for emitting a tubular bundle of light beams in the distal direction of the catheter, a stop surface extending around the tubular arrangement of optical fibres and facing in the distal direction, the stop surface being arranged at a distance proximally from the light emergence surface; characterized in that the light emergence surface slants at a slanting angle in the range of [20°, 60°]—i.e. from and including 20° up to and including 60°—with respect to the longitudinal axis of the catheter.
A catheter provided with such a slanting light emergence surface can and may not be rotated along its longitudinal axis during the cutting procedure. This could result in failure of the cutting procedure, if not in a disaster, because, in case the slanting light emitting surface would be in a position which is not parallel to the wall of the target vessel, not all the laser light beams will impinge on the wall of the target vessel but some or many of them will impinge on the wall of the graft vessel and thus would burn a—not intended—whole in the graft vessel. Further assuming, as is the case during the cutting procedure, the light emergence surface extends close and parallel to the wall surface of the target vessel, the light emergence surface would push the adjacent wall tissue of the target vessel away in case the light emergence surface would be rotated with respect to the longitudinal axis of the catheter. However, it appears that this adjacent wall tissue of the target vessel develops a reaction force counter acting the pushing away of this adjacent wall tissue—thus functioning as a resistance force—and that this reaction force—or resistance force—helps preventing inadvertent rotation of the catheter during the cutting procedure and is slightly tangible for the surgeon. Applicant also surprisingly found that, the laser light beams also perform their cutting action very well in case they impinge upon the wall of the target vessel under an angle of 60° or even 20° (instead of 90°, as is the case in the prior art device).
According to a further embodiment, said slanting angle is in the range of [40°, 50°], such as about 45°. In practise this appears to be a frequently occurring anastomosis angle.
According to another further embodiment, the tubular arrangement of optical fibres has, viewed in a cross-section transverse to the longitudinal axis of the catheter, a circular cross section, wherein, viewed perpendicular to the light emergence surface, the shape of the light emergence surface is elliptical. This ensures that the aperture created in the wall of the target vessel allows for a optimal flow characteristics of the blood flowing from the target vessel into the graft vessel or from the graft vessel into the target vessel.
According to still another further embodiment, the stop surface and light emergence surface are parallel to each other. The stop surface forms locally a radial bulge on the outer surface of the catheter. When the catheter is inserted into the graft vessel, this bulge will be visible as a bulge in the wall of the graft vessel or at least tangible with the fingers of the surgeon. Taking into account that the stop surface and light emergence surface are parallel to each other, this means that the surgeon can use the bulge as a reference for the orientation of the light emergence surface. This enables the surgeon to control or correct the orientation of the light emergence surface with respect to the wall of the target vessel.
In order to remove the flap of wall tissue left after burning away the ring of tissue, it is advantageous to provide the distal part of the catheter with a gripper for gripping tissue inside the tubular bundle of light beams. According to the invention, the gripper preferably comprises a hollow channel extending within the tubular arrangement of fibres and connectable to a vacuum source, wherein the distal end of the channel defines a suction mouth. In order to ensure a reliable cutting through of the wall tissue of the target vessel by the laser light beams as well as a firm gripping of the cut out part of the wall tissue, it is according to the invention advantageous to arrange the suction mouth at a distance proximally from the light emergence surface and so that it defines a suction surface parallel to the light emergence surface. The suction surface parallel to the light emergence surface ensures an easy gripping of the cut out part all over its surface.
According to a further aspect, the invention relates to an assembly for bypass surgery, comprising:
a laser catheter according to the invention; and a ring member having dimensions adapted for, on the one hand, insertion of the distal end of the tubular arrangement of optical fibres through said ring member and for, on the other hand, preventing passage of the stop surface through said ring member.
Before connecting the graft vessel to the target vessel, the graft vessel will be prepared for the bypass procedure by inserting one end of the graft vessel through the ring member and folding back the end of the graft vessel over the ring member. Before using the laser catheter, this folded end of the graft vessel, enclosing the ring member, will be attached to the wall of the target vessel. Subsequently, when the laser catheter has been introduced into the graft vessel and the laser operation is performed, the ring member will prevent the laser catheter from advancing too far into the target vessel as soon as the stop surface comes to rest onto the ring member.
According to a further embodiment of the assembly according to the invention it is advantageous when the ring member has an axial height which is at least 1 mm, such as in the range of [1, 5] mm or preferably in the range of [1, 3] mm, when the ring member has two opposing axial end faces, and when the angle between at least one of said axial end faces and the axial direction of the ring member corresponds to said slanting angle. A ring member having a axial height of at least 1 mm, such as 1 to 3 mm (including both 1 and 3 mm), provides a tubular guide for the distal ends of the optical fibres. This tubular guide helps preventing tilting of the laser catheter with respect to the target vessel during the laser procedure. The angle of the end face of the ring member, which faces the target vessel, being equal to the slanting angle, assists in ensuring that the light emergence surface is kept parallel to the wall of the target vessel during the laser operation. Preferably, both the axial end faces of the ring member are mutually parallel. This provides that the resting surface for the stop surface lies all around the ring member at the same distance from the target vessel.
According to a further embodiment, the assembly according to the invention, further comprises a graft vessel having diameter dimensions allowing, on the one hand, passage of the laser catheter and, on the other hand, insertion through said ring member. According to the invention, this graft vessel can be an artificial vessel as well as a donor vessel obtained from an animal, the patient or another person. Preferably, one end of the graft vessel is inserted through said ring member and folded back over said ring member.
As will be clear, the present invention might be used in many medical fields, especially in the field of surgery of blood vessels. Specific examples of use of the invention are endovascular surgery, especially endovascular bypass surgery, and surgery of intracranial arteries. The present invention might be used with the so called Elana technique.
BRIEF DESCRIPTION OF THE DRAWINGS
Below, the present invention will be described further with reference to the schematic drawing. In this schematic drawing:
FIG. 1 shows a longitudinal cross section of a laser catheter according to the invention;
FIG. 2 shows an end view according to arrow II in FIG. 1 ;
FIG. 3 shows a perspective view of the laser catheter of FIG. 1 ;
FIG. 4 shows a longitudinal cross section of a ring member belonging to an assembly according to the invention;
FIG. 5 shows a perspective view of the ring member of FIG. 4 ;
FIG. 6 shows a longitudinal cross section of a part of an assembly according to the invention;
FIG. 7 shows a sequence of steps in a ETS-anastomosis procedure according to the invention, which FIG. 7 is sub-divided into the FIGS. 7 a , 7 b , 7 c and 7 d ; and
FIG. 8 shows an ETS anastomosis very similar to the one shown in FIG. 7 d , the difference being essentially the design of the ring member.
DETAILED DESCRIPTION OF THE INVENTION
FIGS. 1 , 2 and 3 show a laser catheter 1 according to the invention. The distal part 2 of the laser catheter 1 is provided with a tubular arrangement 3 of optical fibres 4 . The optical fibres 4 have distal ends 5 , which together define a ring-shaped light emergence surface 6 . When a laser source is connected to the proximal ends 28 of the optical fibres 4 , a laser light beam will emit from each of these distal ends 5 of the optical fibres 4 . The distal ends of the optical fibres 4 extend parallel to the longitudinal axis 8 of the catheter, so that the emitted laser light beams will extend parallel to the longitudinal axis 8 in the distal direction indicated by arrow D. This results in a tubular bundle of laser light beams in the distal direction D of the catheter.
The laser catheter 1 further comprises a casing surrounding the tubular arrangement 3 of optical fibres. The tubular arrangement 4 encloses a channel 9 . The proximal end 29 of the channel 9 can be connected to a vacuum source 10 (see FIG. 7 c ) in order to apply a suction force to the channel 9 . The distal end of the channel 9 is provided with a plate, defining the suction surface 13 and provided with suction apertures 12 . The distal end of the channel 9 thus forms a suction mouth 11 , which acts as a gripper when vacuum is applied at the proximal end 29 . The suction mouth is provided at a distance B proximally from the light emergence surface 6 . This distance B will at least be about the thickness of the wall of the target vessel.
The distal end of the casing 25 is provided with a radial bulge 22 . The distal side of the radial bulge 22 forms a stop surface 7 . This stop surface lies proximally at a distance A from the light emergence surface 6 . This distance A will at least be about the axial height H (see FIG. 4 and discussion further below) plus twice the wall thickness of the graft vessel (which follows from FIG. 7 c discussed below) plus the wall thickness of the target vessel 21 (which also follows from FIG. 7 c ).
The laser catheter as described up to here with reference to FIGS. 1 , 2 and 3 is essentially identical to the laser catheter disclosed in EP 750,476, i.e. the differences are not yet addressed.
The distal ends 5 of the optical fibres 4 lie closely packed together with the longitudinal walls of adjacent fibres against each other to form together a tubular arrangement 3 having a circular cross-section as can be seen in FIG. 2 . The distal end faces of all the optical fibres 4 together define an essentially flat light emergence surface 6 , which—according to this invention—slants at an angle α of between 30° to 60° (including both 30° and)60°, preferably about 45°, with respect to the longitudinal axis 8 of the catheter.
Due to the distal ends 5 of the optical fibres being closely packed, the bundle of light beams, which are emitted when a laser light source is connected, form an essentially continuous circular bundle which is capable of burning away a continuous ring of tissue from a target vessel. Rotation of this bundle of laser beams during laser operation for ensuring a complete cut through appears to be superfluous and can be dispensed with.
Due to the slanting light emergence surface, the light emergence surface can lie closely adjacent or against the wall of the target vessel during the laser operation—i.e. the application of the laser beams for burning away tissue—. This results in a very controlled application of the laser beams without the risk that those laser beams damage other surrounding tissue. This also results in that the laser beams, although they impinge under an angle α different from 90°, are still able to transfer sufficient energy to the tissue for burning it away.
In order to ensure a good gripping of the flap 14 ( FIG. 7 c )—i.e. the tissue part separated after burning away the ring of tissue—by the suction mouth 11 , the suction surface 13 of the suction mouth extends parallel to the light emergence surface 6 .
The bulge 22 with the stop surface 7 also extends parallel to the light emergence surface 6 . For the stop function, a bulge and stop surface extending in a plane perpendicular to the longitudinal axis 8 would suffice. This bulge 22 however will provide the surgeon a visible or tangible reference for controlling the position of the light emergence surface with respect to the wall of the target vessel 21 . It will be clear that the bulge 22 is preferably a bulge extending continuously around the catheter, but that, within the scope of the claims, it may also be a discontinuous bulge.
Referring to FIG. 3 , it can be seen that the cross sectional shape—in a plane perpendicular to the longitudinal axis 8 —of the catheter is circular, but that as such the light emergence surface 6 , the stop surface 7 , the bulge 22 and the gripper surface 13 have an oval shape (when viewed in a plane perpendicular to the viewing direction of arrow X in FIG. 1 ).
FIGS. 4 and 5 show a ring member 15 , which together with the laser catheter of FIGS. 1-3 forms an assembly according to the invention. This ring member 15 is preferably made from a material which is inert for the human body, such as a metal alloy like a platinum-iridium alloy. This ring member 15 has a longitudinal axis 30 defining its axial direction. The ring member further has an axial height H of at least about 2-3 mm and two opposing axial end faces 16 , 17 . The axial height of at least about 2-3 mm provides a guiding sleeve for the distal end of the tubular arrangement 3 of fibres 4 , which sleeve prevents tilting of the tubular arrangement 3 of fibres 4 with respect to the sleeve and consequently the target vessel. The two opposing axial end faces 16 , 17 are preferably mutually parallel and have a slanting angle β with respect to the longitudinal axis 30 . The slanting angle β is preferably identical to the angle α (see FIG. 1 ). The angle β of the distal axial surface 16 determines in fact the angle γ (see FIG. 7 a ) of the graft vessel 18 with respect to the target vessel 21 , i.e. the slanting angle of the ETS-anastomosis. The proximal axial end face 17 being parallel to the distal axial end face 16 , has the advantage that the slanting stop surface 7 can come to a firm rest along the entire circumference of the ring member 15 .
FIG. 6 shows a configuration of ring member 15 and a graft vessel 18 , which configuration together with the laser catheter of FIGS. 1-3 forms an assembly according to the invention. The graft vessel 18 can be an artificial vessel or donor vessel originating from an animal, human or the patient itself In all these cases, the configuration shown in FIG. 6 is a prothese ready for implantation into the patient. In case the graft vessel originates from the patient itself the prothese can be prepared well in advance of the ETS-anastomosis procedure or shortly before the actual ETS-anastomosis procedure while the patient is waiting on the operation table.
The configuration of FIG. 6 is obtained by inserting the graft 18 with its distal end stretched (not shown) through the ring member 15 and subsequently folding back the distal end of the graft vessel as is indicated with the arrows E. This folding back can be a complete folding back over 180° as is shown in the drawings with solid lines, but it can, within the scope of the claims, also be a partial folding back as is indicated in FIG. 6 with broken lines 31 .
Referring to FIGS. 7 a - 7 d , a ETS-anastomosis procedure with the laser catheter according to the invention will be described.
FIG. 7 a shows a first step. The graft vessel 18 is attached to the side wall of the target vessel 21 , leaving the part 32 of the wall tissue of the target vessel 21 in front of the lumen of the graft vessel 18 intact so that the blood flow in the target vessel 21 can be left undisturbed as there is no leakage possible. The graft vessel 18 can be fixed to the target vessel 21 by means—not shown—of suture wires, gluing, staples or an other connection technique know from the prior art, which does not require the part 32 of wall tissue to be removed before. The angle γ will be about the same as the angle β (see FIG. 4 ).
After a firm and sufficiently leak tight connection 23 between the graft vessel 18 and target vessel 21 has been established, the laser catheter of FIGS. 1-3 is inserted into the proximal end of the graft vessel 18 , see FIG. 7 b . As can be seen in FIG. 7 b , the bulge 22 on the outer circumference of the laser catheter 1 causes a similar bulge 24 in the wall of the graft vessel. This bulge 24 allows the surgeon to see whether the light emergence surface 6 inside the graft vessel 18 is parallel to the wall part 32 to be removed from the target vessel and to control the correction of the position of the light emergence surface 6 by rotation of the catheter along its axis 8 in case it might not be parallel.
The laser catheter 1 is advanced distally (arrow D in FIG. 7 b ) up to the light emergence surface 6 contacts the wall part 32 to be removed from the target vessel. In case not already done before, the channel 9 and optical fibres 4 are, subsequently, connected to a vacuum source 10 and laser light source 33 , respectively. A vacuum is applied to the channel 9 and the laser procedure is started. Laser light is emitted into the optical fibres 4 . This laser light can be applied continuously or as a series of pulsations, for example during 5 seconds with a frequency of 40 Hz and an energy of about 10-25 mJ. Thus doing, the light emergence surface 6 gradually advances forward through the wall of the target vessel until said surface 6 faces or protrudes into the lumen 34 of the target vessel 21 . The so called flap 14 is gripped by the suction mouth 11 . At this moment, the laser procedure is finished and the laser light source can be switched off Subsequently, the laser catheter is retracted in the direction opposite to arrow D, whilst the flap 14 is being removed by the suction gripper 11 .
As soon as the laser catheter has been retracted over a sufficient distance, a clip 26 ( FIG. 7 d ) is placed on the graft vessel 18 in order to close it off Blood will be allowed to enter the graft vessel through the aperture 27 , but will not be able to pass the clip 26 . After removing the laser catheter completely, the proximal end 20 can be connected by a ETE-anastomosis (ETE=End To End) to another vessel, such as an other graft vessel, or it can be connected by an ETS-anastomosis to the same or another target vessel. The other graft or target vessel might be an artificial vessel or a natural vessel obtained from a donor.
FIG. 8 shows an ETS anastomosis, very similar to the one showed in FIG. 7 d . The difference between FIG. 8 and FIG. 7 d is the design of the ring member. In the embodiment according to FIG. 7 d , the ring member 15 is so to say a short tube, whilst in the embodiment of FIG. 8 , the ring member 115 is so to say a pure ring having an axial height which is smaller than or equal to the radial thickness of the wire from which the ring is made. The ring member 115 will have an oval shape (viewed in a plane parallel to the side wall of the target vessel). Taking into account this difference between FIGS. 8 and 7 d , only the reference number for the ring member is taken differently, the other reference numbers, relating to the same parts, are the same. As will be clear, the embodiment with the ring member 115 also falls within the scope of the claims. Further, it will be clear that the ETS anastomosis of FIG. 8 can be made using the same procedure and laser catheter as shown in the FIGS. 1-7 .
With respect to the ring member 15 , 115 , it is further noted that according to this invention, i.e. within the scope of the claims, this ring member might be provided with one or more protrusions, like anchoring pins, for penetrating through the wall of the graft vessel and/or target vessel.
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The invention is directed to a laser catheter ( 1 ) for bypass surgery, wherein the distal part ( 2 ) of the catheter ( 1 ) is provided with: a tubular arrangement ( 3 ) of optical fibers ( 4 ) having distal ends ( 5 ) defining a ring-shaped light emergence surface ( 6 ) for emitting a tubular bundle of light beams in the distal direction (D) of the catheter ( 1 ); and a stop surface ( 7 ) extending around the tubular arrangement ( 3 ) of optical fibers ( 4 ) and facing in the distal direction (D), the stop surface ( 7 ) being arranged at a distance (A) proximally from the light emergence surface ( 6 ). The light emergence surface ( 6 ) slants at a slanting angle (α) in the range of [20°, 60°] with respect to the longitudinal axis ( 8 ) of the catheter ( 1 ). The invention further relates to an assembly comprising such a catheter.
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FIELD OF THE INVENTION
This invention relates to a continuous recirculation milling process for obtaining small particles of a material, such as pigments for use in paints and compounds useful in imaging elements.
BACKGROUND OF THE INVENTION
Conventional mills used for size reduction in a continuous mode usually incorporate a means for retaining milling media in the milling zone of the mill (e.g., milling chamber) while allowing passage of the dispersion or slurry through the mill in recirculation to a stirred holding vessel. Various techniques have been established for retaining media in these mills, including rotating gap separators, screens, sieves, centrifugally-assisted screens, and similar devices to physically restrict passage of media from the mill. Over the last ten years there has been a transition to the use of small milling media in conventional media mill processes for the preparation of various paints, pigment dispersions and photographic dispersions. This transition has been made possible due primarily to the improvements in mill designs (eg. Netzsch LMC mills and Drais DCP mills) which allow the use of media as small as 250 μm. The advantages of small media include more efficient comminution (ie. faster rates of size reduction) and smaller ultimate particle sizes. Even with the best machine designs available, it is generally not possible to use media smaller than 250 μm due to separator screen plugging and unacceptable pressure build-up due to hydraulic packing of the media. In fact, for most commercial applications, 350 μm media is considered the practical lower limit for most systems due to media separator screen limitations.
PROBLEMS TO BE SOLVED BY THE INVENTION
We have discovered a continuous milling process for preparing extremely fine particles which avoid various problems, e.g., separator screen plugging and unacceptable pressure build up due to hydraulic packing of the media, associated with prior art processes requiring the separation of the dispersed particles from the milling media in the milling chamber.
SUMMARY OF THE INVENTION
We have found that previous problems of media separation during milling can be avoided by 1) adjustment of media separator to allow passage of media through the separator, and 2) providing a means of continuous recirculation of the media/product mixture throughout the process.
One aspect of this invention comprises a continuous method of preparing submicron particles of a compound useful in imaging elements, said method comprising the steps of:
a) continuously introducing said compound and rigid milling media into a milling chamber,
b) contacting said compound with said milling media while in said chamber to reduce the particle size of said compound,
c) continuously removing said compound and said milling media from said milling chamber, and thereafter
d) separating said compound from said milling media.
Another aspect of this invention comprises a continuous method of preparing submicron particles of a compound useful in imaging, said method comprising the steps of:
a) continuously introducing said compound, rigid milling media and a liquid dispersion medium into a milling chamber,
b) wet milling said compound with said milling media while in said chamber to reduce the particle size of said compound,
c) continuously removing said compound, said milling media and said liquid dispersion medium from said milling chamber, and thereafter
d) separating said compound from said milling media.
During the process of the invention, particles of a compound useful in imaging elements and particles of a rigid milling media are continuously introduced into the mill where milling occurs to reduce the average particle size of the compound and are continuously.
ADVANTAGEOUS EFFECT OF THE INVENTION
A material, such as a compound useful in imaging elements, is milled in a continuous process using small particle milling media to obtain submicron particles.
It is another advantageous feature of this invention that there is provided a milling method which enables the use of ultra-fine milling media, e.g., of a particle size less than 300 μm, in a continuous milling process.
Still another advantageous feature of this invention is that there is provided a continuous milling process which avoids problems, e.g., separator screen plugging, associated with prior art processes requiring the separation of the dispersed compound from the milling media in the milling chamber.
Yet another advantageous feature of this invention is that there is provided a method of fine milling compounds useful in imaging elements, which method generates less heat and reduces potential heat-related problems such as chemical instability and contamination.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1-3 are graphs presenting the results obtained in the examples set forth below.
FIG. 4 is a schematic view of a preferred embodiment of a continuous milling process in accordance with this invention.
DETAILED DESCRIPTION OF THE INVENTION
This invention is directed to milling materials, such as pigments for paints and compounds useful in imaging elements, to obtain extremely fine particles thereof. By "continuous method" it is meant that both the dispersed compound and the milling media are continuously introduced and removed from the milling chamber. This can be contrasted to a conventional roller mill process wherein the compound to be milled and the milling media are introduced and removed from the milling chamber in a batch process.
The term "compounds useful in imaging elements" refers to compounds that can be used in photographic elements, electrophotographic elements, thermal transfer elements, and the like. While this invention is described primarily in terms of its application to compounds useful in imaging, it is to be understood that the invention can be applied to a wide variety of materials.
In the invention, media is incorporated as an addenda to the dispersion to be milled at a concentration comparable to that which would exist in the milling chamber of a conventional process. Such media concentrations may vary from 10-95% by volume depending on the application and would be selected based on milling performance requirements and the flow characteristics of the combined mixture of media and dispersion.
Media sizes of interest may range from 5 μm to 1000 μm and media separator gaps would be adjusted accordingly to a size approximately 2X-10X the size of the largest media particles present. Media compositions may include glass, ceramics, plastics, steels, etc.
In a preferred embodiment, the milling material can comprise particles, preferably substantially spherical in shape, e.g., beads, consisting essentially of a polymeric resin.
In general, polymeric resins suitable for use herein are chemically and physically inert, substantially free of metals, solvent and monomers, and of sufficient hardness and friability to enable them to avoid being chipped or crushed during milling. Suitable polymeric resins include crosslinked polystyrenes, such as polystyrene crosslinked with divinylbenzene, styrene copolymers, polyacrylates such as polymethyl methylacrylate, polycarbonates, polyacetals, such as Derlin™, vinyl chloride polymers and copolymers, polyurethanes, polyamides, poly(tetrafluoroethylenes), e.g., Teflon™, and other flouropolymers, high density polyethylenes, polypropylenes, cellulose ethers and esters such as cellulose acetate, polyhydroxymethacrylate, polyhydroxyethyl acrylate, silicone containing polymers such as polysiloxanes and the like. The polymer can be biodegradable. Exemplary biodegradable polymers include poly(lactides), poly(glycolids) copolymers of lactides and glycolide, polyanhydrides, poly(hydroxyethyl methacrylate), poly(imino carbonates), poly(N-acylhydroxyproline) esters, poly(N-palmitoyl hydroxyprolino)esters, ethylene-vinyl acetate copolymers, poly(orthoesters), poly(caprolactones), and poly(phosphazenes).
The polymeric resin can have a density from 0.9 to 3.0 g/cm 3 . Higher density resins are preferred inasmuch as it is believed that these provide more efficient particle size reduction.
Furthermore, Applicants believe that the invention can be practiced in conjunction with various inorganic milling media prepared in the appropriate particle size. Such media include zirconium oxide, such as 95% ZrO stabilized with magnesia, zirconium silicate, glass, stainless steel, titania, alumina, and 95% ZrO stabilized with yttrium.
The media can range in size up to about 100 microns. For fine milling, the particles preferably are less than about 90 microns, more preferably, less than about 75 microns in size and most preferably less that about 50 microns. Excellent particle size reduction has been achieved with media having a particle size of about 25 microns, Media milling with media having a particle size of 5 microns or less is contemplated.
The milling process can be a dry process, e.g., a dry roller milling process, or a wet process, i.e., wet-milling. In preferred embodiments, this invention is practiced in accordance with the wet-milling process described in U.S. Pat. No. 5,145,684 and European Patent Application 498,492, the disclosures of which are incorporated herein by reference. Thus, the wet milling process can be practiced in conjunction with a liquid dispersion medium and surface modifier such as described in these publications. Useful liquid dispersion media include water, aqueous salt solutions, ethanol, butanol, hexane, glycol and the like. The surface modifier can be selected from known organic and inorganic materials such as described in these publications. The surface modifier can be present in an amount 0.1-90%, preferably 1-80% by weight based on the total weight of the dry particles.
In preferred embodiments, the compound useful in imaging elements can be prepared in submicron or nanoparticulate particle size, e.g., less than about 500 nm. Applicants have demonstrated that particles having an average particle size of less than 100 nm have been prepared in accordance with the present invention. It was particularly surprising and unexpected that such fine particles could be prepared free of unacceptable contamination.
Milling can take place in any suitable milling mill. Suitable mills include an airjet mill, a roller mill, a ball mill, an attritor mill, a vibratory mill, a planetary mill, a sand mill and a bead mill. A high energy media mill is preferred when the milling media consists essentially of the polymeric resin. The mill can contain a rotating shaft. This invention can also be practiced in conjunction with high speed dispersers such as a Cowles disperser, rotor-stator mixers, or other conventional mixers which can deliver high fluid velocity and high shear.
The preferred proportions of the milling media, the compound useful in imaging, the optional liquid dispersion medium and surface modifier can vary within wide limits and depends, for example, upon the particular material selected, the size and density of the milling media, the type of mill selected, etc. Milling media concentrations can range from about 10-95%, preferably 20-90% by volume depending on the application and can be optimized based on milling performance requirements, and the flow characteristics of the combined milling media and compound to be milled.
The attrition time can vary widely and depends primarily on the compound useful in imaging elements, mechanical means and residence conditions selected, the initial and desired final particle size and so forth. Residence time of less than about 8 hours are generally required using high energy dispersers and or media mills.
The process can be carried out within a wide range of temperatures and pressures. The process preferably is carried out at t temperature which should cause the compound useful in imaging to degrade. Generally, temperatures of less than about 30° C.-40° C. are preferred. Control of the temperature, e.g., by jacketing or immersion of the milling chamber in ice water are contemplated.
The process can be practiced with a wide variety of materials, in particular pigments useful in paints and especially compounds useful in imaging elements. In the case of dry milling the compound useful in imaging elements should be capable of being formed into solid particles. In the case of wet milling the compound useful in imaging elements should be poorly soluble and dispersible in at least one liquid medium. By "poorly soluble", it is meant that the compound useful in imaging elements has a solubility in the liquid dispersion medium, e.g., water, of less that about 10 mg/ml, and preferably of less than about 1 mg/ml. The preferred liquid dispersion medium is water. Additionally, the invention can be practiced with other liquid media.
In preferred embodiments of the invention the compound useful in imaging elements is dispersed in water and the resulting dispersion is used in the preparation of the imaging element. The liquid dispersion medium comprises water and a surfactant. The surfactant used can be, for example, a polymeric dispersing aid and other surfactants described in copending applications Ser. Nos. 228,839, 228,971, and 229,267 all filed on Apr. 18, 1994, the disclosures of which are incorporated herein by reference.
The compound useful in imaging elements and the milling media are continuously removed from the milling chamber. Thereafter, the milling media is separated from the milled particulate compound useful in imaging elements using conventional separation techniques, in a secondary process such as by simple filtration, sieving through a mesh filter screen, and the like. Other separation techniques such as centrifugation may also be employed.
Suitable compounds useful in imaging elements include for example, dye-forming couplers, development inhibitor release couplers (DIR's), development inhibitor anchimeric release couplers (DI(A)R's), masking couplers, filter dyes, thermal transfer dyes, optical brighteners, nucleators, development accelerators, oxidized developer scavengers, ultraviolet radiation absorbing compounds, sensitizing dyes, development inhibitors, antifoggants, bleach accelerators, magnetic particles, lubricants, matting agents, etc.
Examples of such compounds can be found in Research Disclosure, December 1989, Item 308,119 published by Kenneth Mason Publications, Ltd., Dudley Annex, 12a North Street, Emsworth, Hampshire P010 7DQ, England, Sections VII and VIII, which are incorporated herein by reference, and in Research Disclosure, November 1992, Item 34390 also published by Kenneth Mason Publications and incorporated herein by reference.
Preferred compounds useful in imaging elements that can be used in dispersions in accordance with this invention are filter dyes, thermal transfer dyes, and sensitizing dyes, such as those described below. ##STR1## It is to be understood that this list is representative only, and not meant to be exclusive. In particularly preferred embodiments of the invention, the compound useful in imaging elements is a sensitizing dye, thermal transfer dye or filter dye.
In general, filter dyes that can be used in accordance with this invention are those described in European patent applications EP 549,089 of Texter et al, and EP 430,180 and U.S. Pat. Nos. 4,803,150; 4,855,221; 4,857,446; 4,900,652; 4,900,653; 4,940,654; 4,948,717; 4,948,718; 4,950,586; 4,988,611; 4,994,356; 5,098,820; 5,213,956; 5,260,179; and 5,266,454; (the disclosures of which are incorporated herein by reference).
In general, thermal transfer dyes that can be used in accordance with this invention include anthraquinone dyes, e.g., Sumikaron Violet RS® (product of Sumitomo Chemical Co., Ltd.), Dianix Fast Violet 3RFS® (product of Mitsubishi Chemical Industries, Ltd.), and Kayalon Polyol Brilliant Blue N-BGM® and KST Black 146® (products of Nippon Kayaku Co., Ltd.); azo dyes such as Kayalon Polyol Brilliant Blue BM®, Kayalon Polyol Dark Blue 2BM®, and KST Black KR® (products of Nippon Kayaku Co., Ltd.), Sumikaron Diazo Black 5G® (product of Sumitomo Chemical Co., Ltd.), and Miktazol Black 5GH® (product of Mitsui Toatsu Chemicals, Inc.); direct dyes such as Direct Dark Green B® (product of Mitsubishi Chemical Industries, Ltd.) and Direct Brown M® and Direct Fast Black D® (products of Nippon Kayaku Co. Ltd.); acid dyes such as Kayanol Milling Cyanine 5R® (product of Nippon Kayaku Co. Ltd.); basic dyes such as Sumiacryl Blue 6G® (product of Sumitomo Chemical Co., Ltd.), and Aizen Malachite Green® (product of Hodogaya Chemical Co., Ltd.); or any of the dyes disclosed in U.S. Pat. Nos. 4,541,830, 4,698,651, 4,695,287, 4,701,439, 4,757,046, 4,743,582, 4,769,360, and 4,753,922, the disclosures of which are hereby incorporated by reference.
In general, sensitizing dyes that can be used in accordance with this invention include cyanine dyes, merocyanine dyes, complex cyanine dyes, complex merocyanine dyes, homopolar cyanine dyes, hemicyanine dyes, styryl dyes, and hemioxonol dyes. Of these dyes, cyanine dyes, merocyanine dyes and complex merocyanine dyes are particularly useful.
Any conventionally utilized nuclei for cyanine dyes are applicable to these dyes as basic heterocyclic nuclei. That is, a pyrroline nucleus, an oxazoline nucleus, a thiazoline nucleus, a pyrrole nucleus, an oxazole nucleus, a thiazole nucleus, a selenazole nucleus, an imidazole nucleus, a tetrazole nucleus, a pyridine nucleus, etc., and further, nuclei formed by condensing alicyclic hydrocarbon rings with these nuclei and nuclei formed by condensing aromatic hydrocarbon rings with these nuclei, that is, an indolenine nucleus, a benzindolenine nucleus, an indole nucleus, a benzoxazole nucleus, a naphthoxazole nucleus, a benzothiazole nucleus, a naphthothiazole nucleus, a benzoselenazole nucleus, a benzimidazole nucleus, a quinoline nucleus, etc., are appropriate. The carbon atoms of these nuclei can also be substituted.
The merocyanine dyes and the complex merocyanine dyes that can be employed contain 5- or 6-membered heterocyclic nuclei such as pyrazolin-5-one nucleus, a thiohydantoin nucleus, a 2-thioxazolidin-2,4-dione nucleus, a thiazolidine-2,4-dione nucleus, a rhodanine nucleus, a thiobarbituric acid nucleus, and the like.
Solid particle dispersions of sensitizing dyes may be added to a silver halide emulsion together with dyes which themselves do not give rise to spectrally sensitizing effects but exhibit a supersensitizing effect or materials which do not substantially absorb visible light but exhibit a supersensitizing effect. For example, aminostilbene compounds substituted with a nitrogen-containing heterocyclic group (e.g., those described in U.S. Pat. Nos. 2,933,390 and 3,635,721), aromatic organic acid-formaldehyde condensates (e.g., those described in U.S. Pat. No, 3,743,510), cadmium salts, azaindene compounds, and the like, can be present.
The sensitizing dye may be added to an emulsion comprising silver halide grains and, typically, a hydrophilic colloid at any time prior to (e.g., during or after chemical sensitization) or simultaneous with the coating of the emulsion on a photographic support). The dye/silver halide emulsion may be mixed with a dispersion of color image-forming coupler immediately before coating or in advance of coating (for example, 2 hours). The above-described sensitizing dyes can be used individually, or may be used in combination, e.g. to also provide the silver halide with additional sensitivity to wavelengths of light outside that provided by one dye or to supersensitize the silver halide.
In a preferred embodiment, the compound to be milled and milling media are recirculated through the milling chamber. Examples of suitable means to effect such recirculated through the milling chamber. Examples of suitable means to effect such recirculation include conventional pumps such as peristaltic pumps, diaphragm pumps, piston pumps, centrifugal pumps and other positive displacement pumps which do not use sufficiently close tolerances to damage the milling media. Peristaltic pumps are generally preferred.
Another variation of this process includes the use of mixed media sizes. For example, larger media may be employed in a conventional manner where such media is restricted to the milling chamber. Smaller milling media may be continuously recirculated through the system and permitted to pass through the agitated bed of larger milling media. In this embodiment, the smaller media is preferably between about 1 and 300 μm in mean particle and the larger milling media is between about 300 and 1000μm in mean particle size.
With reference to FIG. 4, the process of this invention can be carried out as follows. The compound useful in imaging elements 10 and rigid milling media 12 are continuously introduced into milling chamber 14 which, as illustrated, contains rotating shaft 16. Peristaltic pump 18 provides the energy to recirculate the dispersion containing both the compound and milling media through the milling chamber to holding tank 20. As opposed to conventional prior art process, there is no means for retaining the milling media within the milling chamber, such as a screen or rotating gap separator.
The following examples illustrate the process of this invention.
EXAMPLE 1
An aqueous premix slurry of a yellow filter dye was prepared by combining the following ingredients with simple mixing:
______________________________________component Amount (g)______________________________________Dye 30Triton X-200 (surfactant) 3Polyvinyl pyrolidone (mw -37,000) 4.5Water 562.5Total 600______________________________________
The dye used has the structural formula: ##STR2##
This slurry was combined with 750 g of polystyrene milling media of an average diameter of 50 μm. The combined mixture of filter dye slurry and media was processed in a 0.6 liter Dyno Mill (Chicago Boiler Company, Buffalo Grove, Ill.) media mill at 3000 rpm for 60 minutes residence time. This processing included continuously recirculating the mixture from a stirred holding vessel through the media mill by means of a peristaltic pump at 100 g/min flow rate. The media separator gap in the media mill, which is normally adjusted to restrict the media to the milling chamber, was adjusted to 500 μm clearance to allow free passage of the media from the chamber back to the holding vessel. This configuration ensured no significant accumulation of media within the milling chamber. A mixture ratio of media:slurry of 1.25 was maintained throughout processing. A processing temperature of 20° C.±5° C. was maintained.
After 60 minutes residence time, the milled slurry was separated from the milling media using an 8 μm filter. Samples of the unmilled premix slurry and milled slurry were characterized for particle size distribution by Capillary Hydrodynamic Fractionation (Matec Applied Sciences, 75 House Street, Hopkinton, Mass., 01748) using a high resolution capillary cartridge Serial #208 and eluted with a 10 wt % dilution GR-500 aqueous eluent.
FIGS. 1 and 2 compare the particle size number and weight distributions for the unmilled premix and milled slurry, respectively. The following table compares the weight average particle diameters for each variation:
______________________________________Sample mean diameter (nm)______________________________________1-1 unmilled premix 164.91-2 milled slurry 123.3______________________________________
As shown, processing with 50 μm media in a continuous media recirculation process resulted in a significant reduction in the average particle diameter and reduced the number of unwanted particles larger than 200 nm.
EXAMPLE 2
A second premix slurry of the same yellow filter dye was prepared as in Example 1. 600 g of this slurry was combined with 1170 g of 75 μm mean diameter polymethyl methacrylate milling media. This mixture was processed as in Example 1 and the particle size distributions of both the premix slurry and milled slurry were measured. The attached FIG. 3 shows the particle size number and weight distributions for the milled slurry relative to the unmilled slurry in FIG. 1. The following table compares the weight average particle diameters for each variation:
______________________________________sample mean diameter (μm)______________________________________2-1 unmilled premix 164.92-2 milled slurry 79.3______________________________________
These data confirm that media of a different size and composition used in the process described in Example 1 may be used to achieve large reduction in mean particle diameter.
EXAMPLE 3
An aqueous premix slurry of a yellow filter dye was prepared by combining the following ingredients with simple mixing:
______________________________________Component Amount (g)______________________________________Dye 40Oleoylmethyltaurine, sodium salt 8Water 752Total 800______________________________________
The dye used in this example has the following structural formula: ##STR3##
The filter dye slurry was processed in a 0.6 liter Dyno Mill media mill at 3000 rpm for 60 minutes residence time. The media mill chamber was charged with 0.48 liters of 500 μm polystyrene milling media, and the media separator gap was adjusted to 100 μm to retain the media in the mill during processing. Processing included continuously recirculating the slurry from a stirred holding vessel through the media mill by means of a peristaltic pump at 100 g/min flow rate. A processing temperature of 20C±5C was maintained during milling. 10 g samples were removed during milling at 10, 20, 40, and 60 minutes residence time and were characterized for particle size distribution as in Example 1.
After 60 minutes residence time, 200 g of 50 μm polystryene milling media was added to the slurry while in recirculation through the media mill. The 50 μm media were of sufficiently small size to allow passage through the agitated bed of 500 μm media in the mill chamber and through the 100 μm media separator gap. In this way milling was accomplished by both the larger 500 μm media and smaller 50 μm in the milling chamber. Samples were removed at 80, 100 and 120 minutes residence time during this stage of milling, and the 50 μm media was removed using an 8 μm filter. The samples were characterized as before.
______________________________________ Residence media size meanSample time (min) (μm) diameter (nm)______________________________________3-1 10 500 277.13-2 20 500 208.13-3 40 500 206.33-4 60 500 191.33-5 80 50 + 500 156.53-6 100 50 + 500 136.93-7 120 50 + 500 124.4______________________________________
After the addition of 50 mm media to the system, there is further particle size reduction to a very small mean diameter. There was no evidence of erosion or fracture of the smaller media by the larger media after processing.
EXAMPLE 4
Another aqueous premix slurry of the same yellow filter dye used in Example 3 was prepared by combining the following ingredients with simple mixing:
______________________________________Component Amount (g)______________________________________Dye 50Oleoylmethyltaurine, sodium salt 10Water 440Total 500______________________________________
This slurry was combined with 625 g of polystryene milling media of an average diameter of 50 μm. The combined mixture of filter dye slurry and media was processed in a 0.6 liter Dyno Mill as in Example 1 for 120 minutes residence time, and samples were removed at 20, 40, 60 and 120 minutes for characterization as before.
______________________________________residence time (min) mean diameter (nm)______________________________________20 245.440 196.160 174.4120 127.3______________________________________
These data confirm that the process described in Example 1 may be applicable to materials of other compositions and be an effective means of particle size reduction for such materials.
The invention has been described in detail with particular reference to certain preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention.
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A continuous method of preparing submicron particles of a compound useful in imaging elements (or other materials, such as pigments, etc.) comprises the steps of continuously introducing the compound and rigid milling media into a milling chamber, contacting the compound with the milling media while in the chamber to reduce the particle size of the compound, continuously removing the compound and the milling media from the milling chamber, and thereafter separating the compound from the milling media. In a preferred embodiment, the milling media is a polymeric resin having a mean particles size of less than 300 μm. The method enables the use of fine milling media in a continuous milling process which provides extremely fine particles of the compound useful in imaging elements while avoiding problems, e.g., separator screen plugging associated with prior art processes requiring the separation of compound from the milling media in the milling chamber.
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FIELD OF INVENTION
[0001] The present inventions relate to dry pipe sprinkler systems or pre-action systems and, more particularly, to auxiliary drains, also known as condensate collectors or drum drips.
BACKGROUND
[0002] A dry pipe sprinkler system or pre-action system comprises a fire suppression system that is typically used in structures and areas that are oftentimes unheated and subject to freezing temperatures. The dry pipe sprinkler system includes a network of pipes including branch lines servicing sprinkler heads, risers, and feed mains for delivering water from a water supply to the branch lines. Under normal conditions, this network of pipes contains a pressurized gas, such as air or nitrogen, which holds closed a dry pipe valve that connects the main supply pipes of main feeds of the sprinkler system to the water supply. When heat from a fire opens a sprinkler, the compressed gas is released from the system. The resulting drop in pressure causes the dry pipe valve to open, or trip, thereby releasing water into the main supply lines or main feeds.
[0003] When the network of pipes is filled with the pressurized gas and the ambient temperature lowers, condensate can collect in the network of pipes. If the condensate builds up in the system, then there is a risk that the condensate will freeze in the pipes. Freezing condensate can cause pipes to leak or burst, or inhibit the flow of water through the branch lines in the event of fire. For this reason, dry pipe systems often include one or more auxiliary drains, also known as condensate collector arrangements or drum drips which collect condensate from the network of pipes. These auxiliary drains are typically located at low points of the dry pipe system and made of a section of larger diameter pipe serving as a condensate collection area, with a smaller diameter pipe at the top and bottom, serving as supply and drain respectively. An upper valve functions as a shut-off valve and a lower valve as a drainage valve. An auxiliary drain is drained of condensate by first closing the upper valve. This prevents pressurized gas from exiting the system when the auxiliary drain is being drained. The drain valve is then opened and condensate is drained from the condensate collection area. Then the drain valve is closed again and the upper valve may be reopened to again allow condensate to be collected.
[0004] Whether an auxiliary drain uses a two valve or other arrangement, it may itself be subject to freezing temperatures, and so be in danger of damage from the condensate it collects freezing and/or alternately freezing and thawing. Such damage could lead to failure of the drain and/or the entire system to which the drain is connected. The damage may be limited through a rigorous drainage schedule and/or insulation on the drain, but such measures may be less than ideal and/or poorly implemented.
SUMMARY
[0005] The preferred embodiments provide apparatus, methods, and articles of manufacture for maintaining the integrity or pressurization of a dry pipe sprinkler system by preventing damage to auxiliary drains from freezing temperatures. A housing is used for providing a controlled environment about an auxiliary drain, insulated and with a heater. The housing is weather resistant and a locking door is provided for access to the auxiliary drain.
[0006] The heater is thermostatically controlled so that it operates when the ambient temperature is below 40 degrees Fahrenheit. There are various entry ways or penetrations into the housing, for the dry pipe, power for the heater and the like, and these are sealed, minimizing penetration into the interior by nuisances such as bees or other unwanted intruders.
[0007] An alarm, which may or may not include a trigger component as used herein, may be provided as well in order to provide warning if said auxiliary drain retains a predetermined amount of condensate. (for example, a float switch alone, a float switch connected to an alarm, etc.) Embodiments may, as well, provide a housing that is retrofit about an existing auxiliary drain or be provided with an auxiliary drain for installation upon a dry pipe sprinkler system.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 shows a view of a preferred embodiment.
[0009] FIG. 2 shows a side view of the embodiment of FIG. 1 .
[0010] FIG. 3 shows a front view of the embodiment of FIG. 1 .
[0011] FIG. 4 shows a side view of the embodiment of FIG. 1 .
[0012] FIG. 5 shows a view of another preferred embodiment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0013] FIG. 1 shows a preferred embodiment with open door 10 . Door 10 is hinged on piano hinge 15 and closes on housing 20 . Door 10 and housing 20 are made of steel and insulated with ½ inch thick foil faced foam board insulation provided to retain heat, as will be further described below. It should be noted that in this and other embodiments alternative construction may be used as well, all of which are intended to be within the scope of the inventions as defined in the claims herein.
[0014] Tabs 21 - 24 are for mounting upon a concrete pillar, wall or other surface as may be desired, and turning briefly to FIG. 5 a schematic of a dry pipe sprinkler system is seen as might be present on a floor of a parking garage or the like with embodiments shown at 1 - 6 depending from corners of the system. Returning to FIG. 1 , key lock 25 and attendant latch 26 is shown on the inside of door 10 . Within housing 20 , auxiliary drain 30 is shown, and is mounted to housing 20 with top u-bolt 28 and bottom u-bolt 29 . Extending from the top of housing 20 is input pipe 31 , which is connected in turn to a dry pipe sprinkler system (not shown.) Upper valve 32 controls input pipe 31 which then leads into condensate collection area 33 . Also at the top of the condensate collection area 33 is float type level switch 35 which allows the unit to fill. As is further described below however if the unit does fill to a preset level, alarm 52 will be triggered. In this and other embodiments, the float type level switch 35 may be set so various levels of condensate may trigger an alarm. Of course, yet other embodiments may dispense with a float type level switch entirely, and an alarm be set to trigger with any amount of condensate. The alarm, it should be noted, may be pre-set, set upon installation, or set during operation, and be set locally and/or from a central location in various embodiments.
[0015] Depending from condensate collection area 33 is lower drainage valve 34 which, when opened, provides for drainage from condensate collector 33 through drain 36 .
[0016] Input pipe 31 travels into housing 20 via pass-through 41 , which, as had been described above, is sealed to prevent nuisances such as bees or other unwanted intruders from entering. There may or may not be a seal, a seal may be water resistant or proofed, other protections as known in the art, etc. may be used as desired in various embodiments. Drain pipe 36 travels through pass-through 46 , which is also sealed in a similar manner to pass-through 41 . Cap 39 can be removed to drain the auxiliary drain 30 , desirably in an appropriate procedure that maintains pressurization, as is described for example in NFPA 25 guidelines. Although the preferred embodiments are within a locking cabinet, and it may not be desired to have an Anti-Trip device, e.g., a wire or plate, other embodiments may use an Anti-Trip device e.g., a wire or plate as desired.
[0017] Thermometer 40 displays the temperature inside the housing 20 though its external dial (not shown.) In various embodiments that temperature may be monitored and an alarm be set to provide warning if the inside temperature fell below a predetermined level. That alarm may be local and/or be sent to a central location as desired. It should be noted that, although the preferred embodiments contain an auxiliary drain, it might be desired in other embodiments to provide a retrofit embodiment to install around an existing auxiliary drain.
[0018] Electrical enclosure 50 contains components for an alarm as well as other components such as circuit protection, a relay and terminal blocks. The alarm 52 extends through recess 53 and provides an audible sound (e.g., buzzer) and light when the auxiliary drain is full of condensate. In other embodiments, it should be noted and as was described above, the alarm may trigger when varying amounts, or any at all, of condensate accumulates. The alarm enclosure 50 is at least a NEMA 4X enclosure in the preferred embodiments as set forth in the National Electrical Manufacturers Association Standards Publication 250-2003.
[0019] Conduit 66 provides power to a heater (or heating element, the words are used interchangeably herein) (not shown here, see FIG. 2 ) and alarm 52 , which in the preferred embodiments is 120V and enters the housing 20 through pass-through 67 , which is sealed similarly to the other pass-through 41 and 46 .
[0020] Turning to FIG. 2 , a side view of the embodiment of FIG. 1 , a heater 65 is behind enclosure 50 . In the preferred embodiments, the heater is sized appropriately, (e.g., a 60 W heater in the preferred embodiments) and provides the interior of housing 20 with an air temperature of from 40 to 60 degrees F., which may be set by thermostat, be preset, allow for setting during or after installation, be set from a central control area, etc.
[0021] It should be noted that embodiments may provide for centralized control as well, with the alarm settings, drainage, heater and other components being monitored and/or manipulated from a central location. Embodiments may include as well a test device to confirm the alarm and other components are working correctly, which may as well be local and/or activated and/or monitored from a central location. The embodiment of FIG. 1 shows a test pushbutton 54 , for example, for testing functionality of the alarm system.
[0022] Turning briefly to FIGS. 3 and 4 , a view of housing 20 with door 10 closed is seen. FIG. 3 is a front view with thermometer 40 , alarm 52 and key lock 25 visible. FIG. 4 is a side view of housing 20 with the door closed.
[0023] The foregoing description is provided as an enabling teaching of the inventions in its currently known embodiments. Those skilled in the relevant art will recognize that many changes can be made to the embodiments described while still obtaining the beneficial results of the present inventions. It will also be apparent that some of the desired benefits of the present inventions can be obtained by selecting some of the features of the present inventions without utilizing other features. Accordingly, those who work in the art will recognize that many modifications and adaptations to the present inventions are possible and may even be desirable in certain circumstances and are a part of the present inventions. Thus, the following description is provided as illustrative of the principles of the present inventions and not in limitation thereof, since the scope of the present inventions is defined by the claims.
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Apparatus, methods, and articles of manufacture for maintaining the integrity or pressurization of a dry pipe sprinkler system by preventing damage to auxiliary drains from freezing temperatures are taught. An insulated, heated housing, which may be thermostatically controlled provides a controlled environment about an auxiliary drain, insulated and with a heater. An alarm may be used as well to provide warning if said auxiliary drain retains a predetermined amount of condensate and embodiments may be retrofit about an existing auxiliary drain or be provided with an auxiliary drain for installation upon a dry pipe sprinkler system.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a step motor controller for accelerating and decelerating a step motor so as to position the motor to the target stop position that changes constantly. More particularly, the invention relates to a step motor controller that reduces beat vibrations resulting from repeated acceleration and deceleration of the step motor connected thereto.
2. Description of the Related Art
Recently, there exist schemes whereby the throttle valves of automotive engines are controlled electronically using step motors. These step motors in the vehicle operate in conjunction with step motor controllers that are used extensively to control the actuation and stopping of the motors.
What is required is to control the opening of each of the throttle valves in keeping with the extent to which the accelerator is operated. The requirement is met by the step motor controller which first of all measures the amount of accelerator operation using a potentiometer or the like. The measured value of the potentiometer is sampled at predetermined intervals and converted from analog to digital format for use as the target value. The controller controls the stop position of the step motor in accordance with that target value, thereby controlling the opening of each of the throttle valves.
The difference between the step motor controller to control the stop position of the step motor for control of the throttle valve opening and ordinary step motor controllers is as follows. For one thing, the amount of accelerator operation varies constantly with the operating status of the vehicle. For another, the opening of the throttle valves needs to be controlled quickly in response to the extent to which the accelerator is operated. On the other hand, for ordinary step motor controllers, the target stop position of the step motor is not supposed to vary at short notice. Thus, with these controllers, what is important is how precisely to drive and stop the step motor to its target stop position in accordance with a predetermined speed pattern.
There have been growing needs for controllers by which to control electronically the amount of accelerator operation by use of the step motor. One such controller for controlling the step motor in opening and closing throttle valves is disclosed illustratively in Japanese Patent Laid-Open No. 138855/1986. The disclosed step motor controller involves comparing the target value designated by accelerator with the current value of the step motor and, if a difference exists between the two values, controlling the revolutions of the step motor in accordance with a previously stored table.
Conventional step motor controllers of the above kind have two major disadvantages.
(1) One major disadvantage is as follows. The step motor controller samples at predetermined intervals the measured value from the potentiometer measuring the amount of accelerator operation. The step motor is controlled so as to approach the target value thus sampled. When the target value becomes constant, the step motor is stopped. It is common practice to rotate the step motor up to the target value as quickly as possible by accelerating the motor at the start of its rotation and by decelerating it when the target value is approached. The process of repeatedly accelerating and decelerating the step motor tends to cause the step motor-driven system, including the throttle valves, to generate beat vibration. The vibration destabilizes the throttle valve positions and thus causes the flow rate of mixture intake into the engine to become unstable. As a result, the speed of the vehicle can fail to keep pace with the extent to which the accelerator is operated.
FIG. 6 is a view showing how a step motor is controlled illustratively by a conventional step motor controller, with the step motor generating vibration. In FIG. 6, reference character M represents those changes in the target value which are taken of the amount of accelerator operation by potentiometer, sampled as analog data at intervals of a predetermined sampling time A, and converted from analog to digital format. The sampling time A is generally about 6 milliseconds (abbreviated as ms hereinafter), determined in view of the tasks of the CPU that provides main vehicle control while also controlling various auxiliary devices configured.
Reference character P denotes the current step that the step motor is in. The current step P is, as shown in FIG. 6, changed step by step. MSPD indicates the condition of the driving pulses applied to the step motor. Specifically, the condition is given in terms of driving frequency and excitation time. The driving frequency and excitation time of each of the conditions given to the step motor are set forth illustratively in the table of FIG. 5. The condition made up of the two values is determined by the difference between the target value and the current position of the step motor.
When the value M varies during operation, a difference MA occurs between the target value and the current position of the step motor. The step motor is then accelerated from MSPD=1 to MSPD=2 to eliminate the difference MA. As the current position of the step motor approaches the target value, the step motor is decelerated from MSPD=2 to MSPD=1 so as to reduce the vibration that will occur upon motor stop.
According to the table of FIG. 5, the total time B during which the step motor is accelerated and decelerated in the above manner amounts to 6.858 ms, as shown in FIG. 6. This is because the excitation time at MSPD=1 is 2,000 μs (2.000 ms) and that at MSPD=2 is 1,429 μs (1.429 ms).
The opening of the throttle valves controlled by the above-described step motor controller is known to generate periodic beat vibration when measured, as indicated by reference character S in FIG. 6. The beat vibration of the throttle valves destabilizes their positions and thus causes the flow rate of mixture intake into the engine to become unstable. The result is that the speed of the vehicle can fail to keep pace with the extent to which the accelerator is operated.
The beat vibration of the step motor, if promoted appreciably, can lead to an out-of-step condition in which the step motor fails to follow the command pulses. This also makes it impossible for the vehicle to keep up in speed with the extent to which the accelerator is operated.
(2) The other major disadvantage of the conventional step motor controller is as follows. When the step motor controller stops the step motor, the step motor-driven system still vibrates for some time and thereby causes the flow rate of mixture intake into the engine to be unstable for a certain period of time. This also results in the failure of the vehicle to keep up in speed with the extent to which the accelerator is operated.
In order to avoid these deficiencies, the conventional step motor controller, illustratively in reversing the step motor, is required to set the throttle valves in the target stop position and keep them there for at least 20 to 30 ms before the reversal. This corrective measure necessarily entails a delay in keeping up with the changes in the extent to which the accelerator is operated.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to overcome the above and other deficiencies and disadvantages of the prior art and to provide a step motor controller capable of minimizing beat vibration when periodically accelerating and decelerating the step motor connected thereto.
In carrying out the invention and according to one aspect thereof, there is provided a step motor controller comprising:
means for inputting target values, the target values representing a value of the rotational position at which the step motor is to be stopped; sampling means for periodically sampling the input target values after a predetermined time interval, the interval being a periodic time other than a time period corresponding to a natural frequency of the step motor drive system; means for determining a difference between the sampled target value and a rotational position of the step motor; and step motor accelerating and decelerating means for accelerating the step motor when the difference is greater than a set value and for decelerating the step motor when the difference is less than the set value.
And in a preferred structure according to the invention, the natural frequency of the system driven by the step motor ranges from 150 to 180 Hz inclusive, and the periodic time lies in a range except for 5.5 m sec-6.8 m sec corresponding to the range of the natural frequency, and the periodic time is desirably set to a range of 6.8 ms-11.0 ms.
In operation, the step motor of the invention actuates the throttle valves of the engine via a step motor-driven system. Experiments show that the natural frequency of the step motor-driven system including the throttle valves and the step motor falls within the range of 150 to 180 Hz. The sampling means of the step motor controller samples the target value from a potentiometer measuring the extent to which the accelerator is operated over time. The step motor accelerating and decelerating means calculates the difference between the sampled target value and the current position of the step motor, accelerates the step motor according to the difference calculated, decelerates the step motor when the current position of the step motor approaches the target value, and stops the step motor at the target value. Thus the acceleration and deceleration of the step motor are repeated at intervals of the sampling time.
The sampling time does not coincide with the period of 6.8 to 5.5 ms corresponding to the natural frequency of the step motor-driven system. Thus when the acceleration and deceleration of the step motor are repeated at intervals of the sampling time, the throttle valves are prevented from resonating with beat vibration. This allows the throttle valves to be controlled with precision, whereby the flow rate of air-fuel mixture intake into the engine is accurately controlled. Because there occurs little beat vibration from the throttle valves when the step motor is stopped, the vibration at motor stop time subsides in a very short time. This provides for a quick response to any new change in the amount in which the accelerator is operated.
These and other objects, features and advantages of the invention will become more apparent upon a reading of the following description and appended drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of a step motor controller embodying the present invention;
FIG. 2 is a view showing how a step motor is controlled illustratively by the embodiment of FIG. 1;
FIG. 3 is a flowchart of steps in which the embodiment works;
FIG. 4 is a data chart indicating typical excitation patterns of a step motor;
FIG. 5 is a data chart listing typical driving pulses for accelerating and decelerating a step motor; and
FIG. 6 is a view showing how a step motor is controlled illustratively by a conventional step motor controller.
DESCRIPTION OF THE PREFERRED EMBODIMENT
One preferred embodiment of the invention will now be described with reference to the accompanying drawings. FIG. 1 is a block diagram of a step motor controller embodying the invention. Referring to FIG. 1, an automotive gasoline engine 11 is connected to an intake pipe 13 that admits a mixture of gasoline and air. The intake pipe 13 is equipped with a throttle valve 12 for adjusting the flow rate of air-fuel mixture into the gasoline engine 11, the valve 12 being held rotatably around a throttle shaft 14. The throttle shaft 14 is connected via a reduction gear to the output shaft of a step motor 15.
The step motor 15 is connected to a step motor driving circuit 18 in a step motor controller 17. The driving circuit 18 is in turn connected to a CPU 19 acting as an operation unit. The CPU 19 is connected to a RAM 23 for temporarily accommodating data and the like, and to a ROM 22 that stores control programs and other resources.
The ROM 22 contains a sampling program 24 that samples the acceleration data measured by a potentiometer 16 at intervals of predetermined sampling time T. The ROM 22 also accommodates a step motor acceleration and deceleration program 25. The program 25 calculates the difference between the sampled value and the current position of the step motor, causes the driving circuit 18 to accelerate the step motor 15 according to the difference calculated, decelerates the step motor 15 when its current position approaches the sampled value, and stops the step motor 15 at the sampled value.
The CPU 19 is connected to an analog-to-digital converter 20 for converting the acceleration data, analog data measured by the potentiometer 16, into digital format. The analog-to-digital converter 20 is connected via an input interface 21 to the potentiometer 16 for measuring the extent to which an accelerator 26 is operated.
The step motor controller 17 of the above constitution works as follows: When the driver of the vehicle operates the accelerator 26, the potentiometer 16 measures the amount of accelerator operation as linear analog data. The CPU 19 admits the analog data from the potentiometer 16 through the input interface 21 at intervals of the sampling time T. The data thus admitted is converted from analog to digital format by the analog-to-digital converter 20. The digitized data is placed in the RAM 23 as the sampled target value. With this embodiment, the sampling time T is, for instance, set for 8 ms.
The sampling time T is set for 8 ms because this sampling time does not coincide with any period corresponding to the natural frequency of the step motor-driven system for actuating the throttle valves 12 of the automotive engine, nor does the time T coincide with any period corresponding to the fractional multiples of that natural frequency. More specifically, the system driven by the step motor 15 has the natural frequency ranging from 150 to 180 Hz, and the fractional multiples of that frequency range from 75 to 90 Hz and from 50 to 60 Hz by multiplying the natural frequency by fractions (for example, 1/2 or 1/3). Thus when preset for 8 ms by the sampling program 24, the sampling time T does not coincide with the periods of 6.8 to 5.5 ms corresponding to the natural frequency (150 Hz-180 Hz), the periods of 13.3 to 11.1 ms corresponding to the frequency of 75 HZ-90 Hz, or the periods of 20.0 to 16.6 ms corresponding to the frequency of 50 Hz-60 Hz.
FIG. 2 shows how a step motor is controlled illustratively by the embodiment. In FIG. 2, reference notation TSTEP denotes the value measured by the potentiometer 16 at intervals of the sampling time T (=8 ms) and converted from analog to digital format. That is, TSTEP is the target step position in which the step motor for actuating the throttle valves 12 is to be stopped. Reference notation STEP indicates the step position the step motor 15 is currently in. The current step STEP is, as shown in FIG. 2, changed step by step. Reference notation MSPD represents the condition of driving pulses given to the step motor 15. Specifically, each of such conditions is composed of a driving frequency and an excitation time, as set forth in FIG. 5.
How the step motor 15 is accelerated and decelerated will now be described. FIG. 3 is a flowchart of steps in which the step motor controller 17, specifically the step motor acceleration and deceleration program 25 therein, operates. The processing of FIG. 3 is started by a timer-based interruption when the step motor 15 completes each of its steps. In step 1 of the flowchart, the current step of the step motor 15 (STEP in FIG. 2) is incremented by 1 toward the target step (TSTEP). In step 2, the step motor acceleration and deceleration program 25 calculates the difference between the target step TSTEP and the current step STEP of the step motor 15, and regards the absolute value of the calculated difference as a step difference DSTEP.
In step 3, the step difference DSTEP is compared with a driving pulse condition MSPD. If the step difference DSTEP is not greater than the driving pulse condition MSPD ("NO" in step 3), step 4 is reached. If the step difference DSTEP is not equal to the driving pulse condition MSPD ("NO" in step 4), step 5 is reached. Now that the step difference DSTEP is found to be smaller than the driving pulse condition MSPD, the value of MSPD is decremented by 1 in step 5. Step 5 is followed by step 7.
If comparing the step difference DSTEP with the driving pulse condition MSPD reveals DSTEP>MSPD ("YES" in step 3), then the value of MSPD is incremented by 1 in step 6. Step 6 is followed by step 7. If the step difference DSTEP is equal to the driving pulse condition MSPD ("YES" in step 4), step 7 is reached without any change in MSPD.
The embodiment involves having a four-phase step motor placed under 1-2 phase excitation control. Thus in step 7, the step motor 15 is excited by use of that pattern in FIG. 4 which corresponds to the low-order three-bit value of the current step of the step motor 15 (STEP) which is characterized by 8 bits. The driving frequency and excitation time of the driving pulses used in the excitation are determined as set forth in FIG. 5. After the stipulated excitation time has elapsed, step 1 is reached again.
The processing of FIG. 3 will now be described in more detail.
When the step motor 15 is in step ST1 of FIG. 2, that step may be taken illustratively as the reference step. In that case, STEP=0; incrementing the step then sets STEP=1 (step 1).
Because TSTEP=6 and STEP=1, DSTEP=5 (step 2). DSTEP>MSPD since MSPD=0 and DSTEP=5 ("YES" in step 3). MSPD is then incremented from 0 to 1 (step 6). An excitation pattern is selected from FIG. 4 based on the low-order three bits of the current step of the motor 15. The selected excitation pattern is applied to the step motor 15 via the driving circuit 18 (step 7). Since MSPD=1, the step motor 15 is fed with driving pulses of a driving frequency of 500 pps (pulse per second) over an excitation time of 2,000 μs (2.000 ms), as set forth in FIG. 5 (step 8). This moves the current position of the step motor 15 (STEP) to step ST2.
Step ST2, in which DSTEP=6-2=4 (step 2) and MSPD=1 ("YES" in step 3), is the same as step ST1 and duplicate description thereof will not be made. MSPD is then incremented to 2 (step 6). The step motor 15 starts to be accelerated toward the target step TSTEP. Now that MSPD=2, the step motor 15 is supplied with driving pulses of a driving frequency of 700 pps over an excitation time of 1.429 ms, as set forth in FIG. 5 (step 8). This moves the current position of the step motor 15 (STEP) to step ST3.
In step ST3, DSTEP=6-3=3 (step 2) and MSPD=2 ("YES" in step 3). MSPD is then incremented to 3 (step 6). The step motor 15 is further accelerated toward the target step TSTEP. Now that MSPD=3, the step motor 15 is supplied with driving pulses of a driving frequency of 843 pps over an excitation time of 1.186 ms, as set forth in FIG. 5 (step 8). This moves the current position of the step motor 15 (STEP) to step ST4.
In step ST4, DSTEP=6-4=2 (step 2) and MSPD=3 ("NO" in step 3). MSPD is then decremented to 2 (step 5). The step motor 15 starts to be decelerated toward the target step TSTEP. Now that MSPD=2, the step motor 15 is supplied with driving pulses of a driving frequency of 700 pps over an excitation time of 1.429 ms, as set forth in FIG. 5 (step 8). This moves the current position of the step motor 15 (STEP) to step ST5.
In step ST5, DSTEP=6-5=1 (step 2) and MSPD=2 ("NO" in step 3). MSPD is then decremented to 1 (step 5). The step motor 15 is further decelerated toward the target step TSTEP. Now that MSPD=1, the step motor 15 is supplied with driving pulses of a driving frequency of 500 pps over an excitation time of 2.000 ms, as set forth in FIG. 5 (step 8). This moves the current position of the step motor 15 (STEP) to step ST6.
In step ST6, the total excitation time B1 accumulated from step ST1 on amounts to 8.044 ms. With the sampling time T=8 ms, the target step TSTEP is changed to 12. Because DSTEP=12-6=6 (step 2) and MSPD=1 ("YES" in step 3), MSPD is incremented to 2 (step 6). The step motor 15 is then accelerated toward the target step TSTEP. Further, similarly to the above, driving process of the step motor 15 is conducted according to the flowchart in FIG. 3.
As shown in FIG. 2, the periods in which to accelerate and decelerate the step motor 15 are: B1=8.044 ms, B2=8.270 ms, and B3=8.270 ms. These periods do not coincide with the period of 6.8 to 5.5 ms corresponding to the natural frequency of 150 to 180 Hz of the system driven by the step motor 15 to actuate the throttle valves 12; or with the period of 13.3 to 11.1 ms or that of 20.0 to 16.6 ms corresponding to those fractional multiples of the natural frequency which range from 75 to 90 Hz and from 50 to 60 Hz.
As described above in detail, the step motor controller 17 of the invention has the sampling time T not coinciding with the period of 6.8 to 5.5 ms corresponding to the natural frequency of 150 to 180 Hz of the system driven by the step motor 15, or with the period of 13.3 to 11.1 ms or of 20.0 to 16.6 ms corresponding to those fractional multiples of the natural frequency which range from 75 to 90 Hz and from 50 to 60 Hz. This connotes that accelerating and decelerating the step motor 15 substantially at intervals of the sampling time does not induce in the throttle valves 12 any resonance with beat vibration, as shown in FIG. 2 by the curvature S. The throttle valves 12 are thus controlled with accuracy, whereby the amount of mixture intake into the engine 11 is precisely controlled. Because stopping the step motor 15 causes little beat vibration in the throttle valves 12, the vibration that does occur at motor stop time subsides in a very short time. This provides for a quick response to any new change in the amount in which the accelerator is operated.
Although the description above contains many specificities, these should not be construed as limiting the scope of the invention but as merely providing illustrations of the presently preferred embodiment of this invention. For example, although the sampling time is set for 8 ms with the above embodiment, any other sampling time will do as long as it does not coincide with the periods of 6.7 to 5.6 ms, 13.3 to 11.1 ms or 20.0 to 16.6 ms; such sampling time will not permit the step motor-driven system for actuating the throttle valves to develop resonance. It should be noted that a sampling time of 20 ms or more can pose problems in keeping up with detecting changes in the amount of accelerator operation; the sampling time should preferably be between 6.8 ms 11.0 ms, or 5.5 mm and less. In another example, although the above embodiment is a step motor controller for actuating the throttle valves, the invention may be applied to any other setups in which the step motor is required to respond quickly to a constantly changing target value.
To sum up, the step motor controller of the invention has a sampling time not coinciding with the period corresponding to the natural frequency of the system driven by the step motor, or with the period corresponding to the fractional multiples of the natural frequency. Because accelerating and decelerating the step motor substantially at intervals of the sampling time does not induce in the throttle valves any resonance with beat vibration, the throttle valves are controlled with accuracy. This in turn allows the amount of mixture intake into the engine to be controlled precisely. Because stopping the step motor entails little beat vibration in the throttle valves, the vibration that does occur at motor stop time settles in a very short time. This ensures a quick response of the step motor-driven system to any new change in the amount of accelerator operation.
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A step motor controller including a sampling program for sampling, at predetermined intervals, input target values that represent a position of the step motor. The difference between the sampled target value and a rotational position of the step motor is obtained. A step motor accelerating and decelerating program accelerates the step motor upon finding the difference between the sampled target value and the current position of the step motor is greater than a set value. When the difference is less than the set value the step motor is decelerated. The predetermined sampling time does not correspond to the natural frequency of the step motor system or to a period corresponding to a fractional multiple of the natural frequency.
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BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
This invention relates to a tool for inserting and deploying a medical graft within a body cavity, such as a blood vessel, and more particularly, to a tool for inserting and deploying such graft in a femoral-popliteal artery during an intraluminal graft procedure.
BACKGROUND INFORMATION
Balloon angioplasty and atherectomy have generally not proven to be viable long term options in the treatment of extensive atherosclerotic lesions in femoral-popliteal arteries. Good results are only obtainable with such methods when the flow limiting lesions are short and discrete. It is thus apparent that patients with extensive occlusive disease in a femoral-popliteal artery are presently best treated by bypass surgery. Conduits for such bypass surgery can be either autogenous, such as saphenous vein, or synthetic, such as tetrafluoroethylene polymer sold under the brand name "Goretex". The choice of the graft type employed depends on the preference of the surgeon and on the integrity of the outflow tract. This technique is an effective long term option, with patency rates in the 80 percent range for selected cases. This procedure is one of the most common graft procedures, with 25,000 to 30,000 cases being treated each year.
In accordance with the standard procedure for providing such a bypass, a surgical cutdown is performed in the groin area and in the leg, thereby providing cutdowns above and below the diseased portion of the blood vessel to be bypassed. A tunnel is made along side the diseased artery between the cutdown areas, and the graft or prosthesis is passed through the tunnel. After the graft or prosthesis is sutured to the femoral end of the artery at the cutdown in the groin area and to the popliteal end of the artery at the lower cutdown, blood flow is restored through the affected leg. This procedure generally takes 21/2 to 3 hours, with a recovery time lasting 5 to 6 days. Disadvantages of this procedure include the requisite spinal or general anesthesia, the requirement for two incisions, the length of surgery, with significant morbidity and mortality, and the length of time required for recovery.
DESCRIPTION OF THE PRIOR ART
A number of U.S. patents describe methods for inserting a radially expandable, generally tubular prosthesis, stent or graft in a blood vessel. The prosthesis has a contracted state, in which it is carried to a diseased portion of the blood vessel by means of an insertion tool, and a radially expanded state, which it assumes upon being released by the insertion tool. The insertion tool includes means for holding the prosthesis in its contracted state, whereby narrow and obstructed blood vessels can be traversed. After the deployment, the expansion of the prosthesis forms a central hole suitable for blood flow and, with radial compression forces, seats the prosthesis in place within the blood vessel. After the procedure, the prosthesis continues to be held in place by these compression forces
For example, U.S. Pat. No. 4,665,918, issued to Garza et al on May 19, 1987, describes an implant tool having an outer sheath covering the prosthesis and holding it in a contracted state during the insertion procedure The outer sheath is slidably mounted over a delivery catheter and within a tubular outer catheter. At the proximal end of the device, a first pair of locking arms, variable in effective length through attachment at a plurality of notches, is used to determine how far the delivery catheter extends from the outer catheter; and a second pair of locking arms is used to hold the sheath in place over the prosthesis. When the obstructed portion of the blood vessel is reached, this second pair of locking arms is removed, and the outer sheath is pulled outward, uncovering the prosthesis, which expands radially, pushing away obstructive material in the blood vessel and providing a clear central hole, through which the distal tip of the insertion tool is withdrawn.
In another such example, U.S. Pat. No. 4,732,152, issued to Wallsten et al on Mar. 22, 1988, describes an insertion tool having an outer tip portion consisting of a hose folded back within itself, leaving a double-walled cavity in which a prosthesis is held in its contracted state. The hose is connected to a pressurized cylinder, which is slid outward on a central shaft, pulling the fold in the hose outward to expose the prosthesis, which then expands in the blood vessel. Alternative embodiments of the insertion tool include an inflatable balloon ahead, behind, or around the double-walled cavity, provided for widening the blood vessel before the prosthesis is released at a desired location.
U.S. Pat. No. 4,875,480, issued to Imbert on Oct. 24, 1989, describes a means for providing the circulation of a liquid flushing medium to remove gasses, such as air, which might be trapped in the cavity with the prosthesis prior to deployment of the prosthesis. Means are also described for flushing gasses from the folded back part of the hose to eliminate the danger of releasing gasses into the bloodstream in the event of a rupture in the hose.
U.S. Pat. No. 4,771,773, issued to Kropf on Sep. 20, 1989, describes an insertion tool for placing a prosthesis in the form of a helical spring within a blood vessel. In a released, or deployed state the prosthesis has a larger diameter. For insertion the prosthesis is wound, by the rotation of one end, tightly on a mandrel forming a part of the insertion tube, having a diameter smaller than the inner diameter of the prosthesis. Each end of the prosthesis is fastened to one of a pair of axially separated fasteners, which are in turn mutually connected by a transmission in the area of the mandrel. The transmission allows relative rotation of the fasteners only in the direction which tightens the helical prosthesis, until a clutch is actuated to allow rotation in the opposite direction. Alternately, one of the fasteners includes a triggering member which releases the associated end of the helical prosthesis. The clutch or triggering member can be actuated from the end of the insertion tool opposite to the mandrel.
U.S. Pat. No. 5,026,377, issued to Burton et al on Jun. 25, 1991, describes an insertion tool for deploying a self-expanding tubular prosthesis, or stent, which is preferably a braided type, within a body canal, such as a blood vessel. The tool includes an elongated tubular outer sleeve, having disposed therein an elongated core which is movable relative to the sleeve. The core has a grip member, at or near its distal end, which is adapted to releasably hold the prosthesis within the outer sleeve. This grip member, which provides a high-friction contact surface between the prosthesis and the core, may be a sleeve or coating of a material which takes a set, such a polyurethane, attached to the core. The prosthesis is carried through the blood vessel, in a contracted state, being held in an annular space between the grip member and the outer sleeve. When the correct position is found, deployment of the prosthesis is begun by pulling the outer sleeve backward, allowing the distal end of the prosthesis to expand against the walls of the blood vessel. If the position of the prosthesis, which is then checked by fluoroscopy is correct, the outward motion of the outer sleeve is continued to release the entire prosthesis; otherwise the outer sleeve is moved back inward to retract the part of the prosthesis which has been extended, and the prosthesis is repositioned as desired. During these motions, the prosthesis is held in position relative to the core by contact with the grip member.
While the prior art devices described above rely on the release of mechanical energy stored in the prosthesis to provide compressive forces necessary to hold the prosthesis in place, the intraluminal grafting system described in U.S. Pat. No. 4,787,899, issued to Lazarus on Nov. 29, 1988, employs a pressurized expandable membrane, operating inside a generally cylindrical prosthesis within a blood vessel, to force the points of staples fastened to the outside of the prosthesis outward into the walls of the blood vessel. This device is described for use in the repair of a damaged vessel, such as an aneurysm or a torn vessel. The insertion tool includes a flexible rod and a tube arranged to be slid along the axis of the rod. The distal end of the rod mounts a cup, having an open end facing away from the distal tip, in which a collapsed prosthesis is carried, extending around the distal end of the tube. The prosthesis is preferably made of nylon, dacron, or Teflon, having a number of circumferential bifolds along its length. The expandable membrane forms a part of the distal portion of the tube. To deploy the prosthesis, the expandable membrane is inflated, and the tube is pulled outward, dragging the prosthesis out of the cup and forcing it against the walls of the blood vessel The expansion of the prosthesis forms a large enough internal hole to allow the subsequent withdrawal of the cup.
The prior art intraluminal grafting systems described above each require a special type of graft material formable into a compressed state, and releasable into an expanded state. Thus, these systems share the disadvantage of not being adaptable for the deployment of the types of material commonly used in graft procedures, such as the ribbed Goretex tetrafluoroethylene polymer typically used in femoral-popliteal artery bypass operations.
Furthermore, except for the system described in U.S. Pat. No. 4,787,899 to Lazarus, the prior art systems require that the mechanical strain energy stored within the graft material in its contracted state must exert enough pressure on the walls of the blood vessel to hold the prosthesis in place. U.S. Pat. No. 4,787,899 to Lazarus, on the other hand, depends on staples to perform this function. Thus, none of these systems is configured to be used with the common, effective, reliable and approved method of suturing graft material into the healthy portion of a blood vessel. Further, none of the prior art systems can readily utilize commercially available grafts, which have previously been tested and approved by appropriate authorities.
SUMMARY OF THE INVENTION
In accordance with one aspect of the invention, there is provided apparatus for the intraluminal insertion and deployment of a medical graft within a blood vessel. The apparatus includes a shaft having a tapered tip at a distal end and a body extending from the tapered tip to a proximal shaft end. The medical graft is slideably mounted on the body remote from a distal portion of the shaft. The apparatus further includes a sheath having a proximal portion slideably mounted over the medical graft, the sheath having a distal end removably engaging the distal portion of the shaft to form a taper towards the tapered tip of the shaft. The sheath is fixedly maintained over the medical graft and engages the distal portion of the shaft during insertion and the shaft and sheath are removable for deployment of the medical graft.
BRIEF DESCRIPTION OF THE DRAWINGS
Preferred versions of the subject invention are hereafter described with specific reference being made to the following Figures, in which:
FIG. 1 is an axial cross-sectional view of an intraluminal insertion tool built in accordance with this invention, shown operating on a guide wire;
FIG. 2 is a partly sectional side elevation of the sheath used as a part of the tool of FIG. 1;
FIG. 3 is an isometric view of the distal tip portion of the sheath of FIG. 2;
FIG. 4 is an axial cross-sectional view of a guide funnel provided as an accessory for the assembly of the tool of FIG. 1;
FIGS. 5 through 8 show the manner of assembling the various components of the tool of FIG. 1;
FIG. 9 is an axial cross-section view of an alternative version of the intraluminal insertion tool, including a heated tapered distal section; and
FIG. 10 is an axial cross-sectional view of a second alternative version of the intraluminal insertion tool, including an integral angioplasty balloon.
DETAILED DESCRIPTION
An insertion tool 10 used for performing an intraluminal bypass-type medical procedure in a blood vessel, such as the femoral-popliteal artery, with a conventional and commercially available ringed synthetic graft material, is shown in FIGS. 1 through 8.
Referring first to FIG. 1, insertion tool 10 includes a distal end 12, which extends into the human body during the insertion of a synthetic blood vessel graft 14, and a proximal end 16, which remains outside of the human body, and which is used to manipulate the insertion system so that synthetic graft 14 is delivered to the desired location. Graft 14 is preferably made of a synthetic material, such as a tetrafluoroethylene polymer, and is sold under the brand name "Goretex" by W. L. Gore, of Arizona. Graft 14 includes a number of spaced integral rings 15 around its outer surface, for providing stiffness and to prevent collapse in use, while allowing the flexibility required to traverse the vascular system and to bend with subsequent motion of the patient.
Tool 10 is designed to carry graft 14 into the body on an insertion shaft 18, while graft 14 is covered by a shield, or sheath 19, as tool 10 is advanced within the body. When the proper location for graft 14 is attained, a safety lock tube 20, which holds sheath 19 in place during insertion, is disengaged and removed from insertion shaft 18, and sheath 19 is slid outward from the body, off the proximal end of shaft 18, outwardly exposing graft 14. Insertion shaft 18 is then pulled outward from the body, while a deployment slider 21 is held in place, so that graft 14 is deployed, being left in place within the body.
Insertion shaft 18 extends the length of tool 10, having a male fitting 22 of a type which can be rotationally locked or unlocked from a mating female fitting, such as a luer fitting, at a proximal end, permitting the attachment of standard medical accessories, such as syringes or hemostasis valves. Shaft 18 also includes an axial hole 23 extending its entire length to allow the infusion or aspiration of a fluid and/or to allow the passage therethrough of a guide wire 24, which may be of a conventional type having a "J"-shaped hook at a distal end 26 and a straight proximal end 28. Insertion shaft 18 is fabricated from a somewhat flexible material, such as polycarbonate and may have a diameter of approximately six millimeters, or less, thereby permitting a slight flexure during insertion into an removal from the body. The distal end of insertion shaft 18 has a tapered tip 30, which dilates the treatment area of the body as shaft 18 is advanced into the human body. A circumferential slot 32 extends inward around insertion shaft 18 at an angle pointing toward tapered tip 30. Slot 32 may be axially displaced along the cylindrical portion of shaft 18 by between 2.5 to 12.7 millimeters from the adjacent end of tapered tip 30 and the depth of slot 32 may be from 1.3 to 2.5 millimeters.
The length of insertion shaft 18 depends on the procedure to be accomplished, and particularly on the length of the synthetic graft 14 to be inserted. For intraluminal femoral-popliteal artery procedures, a graft 14 may typically be 300 to 350 mm in length. Insertion shaft 18 must be somewhat longer than twice the length of graft 14 to accommodate the remaining components of tool 10 and to allow tool 10 to be manipulated as intended. The diameter of shaft 18 is selected approximate the inner diameter of graft 14 so that graft 14 closely fits over shaft 18.
FIGS. 2 and 3 show sheath 19 in more detail. Sheath 19 forms the outer portion of insertion tool 10 during the insertion procedure. As seen in FIG. 2, sheath 19 has a thin tubular portion 36 and a relatively rigid collar 38, which, as discussed hereafter, provides a grip for the physician at the proximal end of sheath 19. Four or more Vee shaped cuts 37 are made at the distal end of sheath 38, thereby forming tabs 42 which may thereafter be pressed together to form a tapered end 40, as best seen in FIG. 3, when tabs 42 are inserted in slot 32.
When sheath 19 is assembled on insertion shaft 18 in the manner shown in FIG. 1, tabs 42 fit within slot 32 of shaft 18. A guide funnel 52, seen in FIG. 4, is provided as an accessory to assist in the assembly of tabs 42 into slot 32. Guide funnel 52 has a cylindrical outer surface 54, an axial hole 56, and an internal truncoconical surface 58. After sheath 19 is moved completely past slot 32, guide funnel 52 is placed over tapered tip 30 of shaft 18, to be held in place while sheath 19 is moved toward the distal end of tool 10. This motion causes the inward deflection of tabs 42 upon contacting truncoconical surface 58, so that tabs 42 are simultaneously fed into slot 32. After sheath 19 is slid fully forward, guide funnel 52 is removed from tool 10.
Since sheath 19 covers graft 14 during its advancement into the body on insertion shaft 18, prior to final deployment, sheath 19 must be constructed of a material, such as a tetrafluoroethylene polymer, which slides easily through the body. Alternately, other materials with low friction surfaces or slippery coatings, such as hydrogel, may be used. When flexible tabs 42 are held within slot 32, the distal end of sheath 19 is maintained in a tapered configuration, which permits further dilation of the treatment area of the body through which the insertion tool 10 is advanced. The internal diameter of sheath 19 must be large enough to allow sheath 19 slide over graft 14 during the assembly of tool 10 and during the deployment of graft 14 within the body. To facilitate the advancement of tool 10 through the body, it is desirable that the distance from the inner to outer surfaces of tubular portion 36 be as thin as possible, consistent with requirements for strength and stiffness which may be placed on sheath 19 during the usage of tool 10.
Referring now to FIGS. 5 through 8, the manner of assembling tool 10 and graft 14 is shown. First, as seen in FIG. 5, deployment slider 21 is inserted on shaft 18 and then graft 14 is inserted on shaft 18 in front of slider 21. The resulting subassembly after slider 21 and graft 14 are assembled is seen as the left portion of FIG. 6. As seen, the length of slider 21 and graft 14 substantially equals the length of shaft from fitting 22 to slot 32. Graft 14 is selected to be the appropriate length for the medical procedure to be performed and preferably, the length of deployment slider 21 takes up the remaining available length of shaft 18. Next, as seen in FIG. 6, sheath 19 is inserted over graft 14 and the tabs 42 are inserted into slot 32 using guide funnel 52. At this point, the partially assembled tool 10 appears as in the right portion of FIG. 7. Lastly, as seen in FIG. 7, safety lock tube 20 is slid over deployment slider 21 and against the back end of sheath 19. Then, safety lock tube is rotated 90 degrees and becomes locked with fitting 22 at the proximal end of shaft 18. In this position, safety lock tube maintains tabs 42 of sheath 19 fixedly engaged in slot 32. Now, tool 10 is completely assembled as seen in FIG. 8, and ready for use.
As assembled in FIG. 8, tool 10 is ready for insertion into a body for the purpose of placing graft 14 in the body. For example, graft 14 may be used as a bypass for a blocked artery, such as the femoral-popliteal artery in a patient's leg. The procedure for inserting tool 10 includes first identifying the area to be bypassed. If the bypass area is a blockage in an artery, an inccision is made to expose the lumen of the artery on the proximal side of the blockage. Next, the distal or "J" end 26 of a conventional guide wire 24, as seen in FIG. 1, is inserted within the exposed artery to a point on the distal side of the blockage, with the proximal end 28 of the guide wire 24 remaining outside of the body. Next, tool 10 is guided into the exposed artery by axial hole 23 being inserted over the proximal end 28 of guide wire 24. Tool 10 is then inserted into the interior of the artery through the incision in the artery until the distal end of graft 14 is beyond the blockage. During insertion, tool 10 is guided through the artery by guide wire 24 in a well known manner. In assembling tool 10, the length of graft 14 is selected to be appropriate for the blockage area to be relieved and the length of slider 21 is preferably selected to take up the remaining length of shaft 18. Sheath 19 is further selected to somewhat longer than graft 14, so that when tool 10 is fully inserted, collar 38 of sheath 19 remains outside of the patient's body.
The process of deploying graft 14 into a body begins with safety lock tube 20 being rotated to the unlocked position and then being slidably removed. Then, collar 38 is grasped and sheath 19 is slid outward over deployment slider 21. During this step, tabs 42 are removed from slot 32 and expand to slide over deployment slider 21 as well. After sheath 19 is removed, graft 14 is exposed within the artery, which collapses against the outer surface thereof. The presence of rings 15 particularly maintains graft 14 firmly in place so that it is not easily moved as guide wire 24, slider 21 and lastly shaft 18 are removed. However, to assure that graft 14 remains in position, removal may proceed by the physician holding slider 21 against graft 14 while first removing shaft 18. After shaft 18 is removed, rings 15 provide the strength required to prevent graft 14 from collapsing. After tool 10 is completely removed from the body, the proximal end of graft 14 is preferably attached, by suturing, to a healthy portion of the artery, above the diseased section, and blood flow is restored.
One particular advantage obtained from using tool 10 is that a wide variety of commercially available and thoroughly tested and approved forms of graft material may be used, instead of requiring the use of special forms of graft material having a radially contracted state during insertion and a radially expanded state after deployment, as taught in the prior art. Examples of tools and systems requiring such radially expandable or self-expanding grafts are found in U.S. Pat. No. 4,665,918 to Garza, U.S. Pat. No. 4,732,152 to Wallsten et al, U.S. Pat. No. 4,771,773 to Kropf, U.S. Pat. No. 4,787,899 to Lazarus, U.S. Pat. No. 4,875,480 to Imbert, and U.S. Pat. No. 5,026,377 to Burton et al.
It should be noted that safety lock tube 20 includes a luer type fitting 46 for the attachment to standard medical devices and an axial hole 48 extending through its proximal end and aligned with axial hole 23 when attached. This structure permits the infusion or aspiration of fluid by means of axial hole 23 in insertion shaft 18. During the advancement of tool 10 through a blood vessel, a contrast medium can be infused through axial holes 48 and 23 to allow visualization of tool 10 relative to body structures under fluorosoopy. Placement of the guide wire 24 through axial holes 48 and 23 into the body assists in navigation of tool 10 through the body, thereby increasing the safety of procedures using tool 10 by following well established practices of guide wire navigation. The diameters of axial holes 48 and 23 are large enough to permit the simultaneous extension of a guide wire and fluid motion therethrough.
In one version of insertion tool 10, tapered tip 30 of insertion shaft 18 may include a metal band 50 which becomes visible under fluoroscopy to provide information to the physician regarding the location of tool 10 inside the body. Alternately, tip 30 can be made using a radio-opaque material of many different types.
As noted above, to prepare for the performance of an intraluminal graft procedure a proper length of graft material 14 must be loaded into the tool 10 and the other components have lengths based upon the length of graft and/or the length of shaft 18. It is anticipated that appropriate lengths of graft 14 and deployment slider 21 will be provided in separate, sterile packages, and that a surgeon will typically have several lengths of insertion tools 10 to be used with several corresponding lengths of graft material. Alternately, fully assembled insertion tools 10 may be supplied in sterile packaging with differing lengths of graft 14 pre-loaded therein, ready for the insertion procedure.
As indicated above, one anticipated application of insertion tool 10 is in the treatment of severe occlusive disease in the peripheral arterial system, particularly in the installation of an intraluminal graft in a femoral-popliteal artery. In this procedure, a single incision is made to expose the affected artery and the diseased artery is traversed, employing either a guide wire or an arthrectomy device. In some patients, an angioplasty balloon may first be used to dilate the artery to a diameter of six to seven millimeters. While balloon angioplasty is not generally successful when applied to a lone segment of occluded femoral-popliteal artery as a treatment, it is often a useful initial procedure to open the artery for the subsequent insertion of graft material.
It is anticipated that the medical procedure described herein can be performed under a local anesthetic in one to two hours with a hospitalization of only a few of days. Thus, significant advantages are gained over the conventional procedure, which requires cutdowns to the artery in both the femoral and popliteal locations, the formation of a tunnel space, adjacent to the diseased artery for the deployment of a bypass graft, and suturing of the graft to the artery at both ends. Such conventional procedures, of course, must be done under a general anesthetic and require significantly longer surgical and recovery times.
Referring now to FIG. 9, an insertion tool 60 is shown having an insertion shaft 62 extended and otherwise modified to provide a tapered tip 64 with a circumferential heating element 66, which may be used to soften the treatment site and to assist in the dilation effect needed to advance tool 60 through the body. The temperature range used at this heating element may be from 40 degrees C to 200 degrees C. Heating element 66 may include an inner layer of electrically resistant material, thereby permitting heating by direct current, covered by metal or of some other material capable of sustaining and transmitting the required heat. In tool 60, insertion shaft 62 is formed of a thermoplastic material molded around electrical wires 70 or around wire lumens extending from electrical connectors 72 to heating element 66. A narrow slot 74, extending longitudinally along the tubular portion of safety lock tube 76, allows the assembly and operation of tube 76 as previously described relative to safety lock tube 20 of insertion tool 10, with wires 70 extending outward to connectors 72 through slot 74. Alternately, heating element 66 may be activated by radio frequency energy as can be appreciated by those skilled in the art.
Electrical connectors 72 provide an interface at which wires 70 are connected to a controllable source of electrical current. A number of well known methods for providing and controlling electrical current can be used to control the temperature of heating element 66. For example, a thermistor (not shown) can be located adjacent to heating element 66 to provide an indication of the temperature, with feedback from the thermistor being used to regulate the electrical current provided to element 66.
Referring now to FIG. 10, a cross-sectional view of a second alternative insertion tool 76 is shown. Tool 76 has been modified relative to tool 10 to support an inflatable membrane forming an angioplasty balloon 78 extending from tapered tip 80 of insertion shaft 82. An extended distal cylindrical shaft section 84, having a diameter less than that of main shaft section 86, and a length of 10 to 300 millimeters, is provided for the attachment of balloon 78. A small hole 88, extending along the length of shaft 82, is used to provide a fluid, such as saline solution, water, or contrast media, to inflate balloon 78 at a pressure from one to twenty atmospheres. If insertion shaft 82 is made using a thermoplastic molding process, hole 88 may be provided by including a small diameter multi-lumen extension in the mold as a insert.
Balloon 78 may have an outer diameter of four to thirty millimeters and a length of ten to 200 millimeters and it may be fabricated from irradiated polyethylene, polyvinyl chloride, or other suitable balloon materials well known to those skilled in the angioplasty art. A distal tip 90 of distal shaft section 86 is also tapered, having a profile similar to that of conventional angioplasty catheters. Hole 88 is connected to a tube 90 extending outward to a small luer type fitting 92, which provides a capability for connection to standard medical accessories (not shown). A slot 94 extends along the tubular portion of safety lock tube 96, providing for the installation and removal of tube 96 around outward extending tube 90.
In its anticipated usage, tool 76 provides an additional advantage in simplifying operative procedure by combining the angioplasty procedure required to open the clogged artery, so that the tool can be advanced therethrough, with the advancement of the tool. When compared to the prior art embodiments including angioplasty balloons described in U.S. Pat. No. 4,732,152 to Wallsten et al and U.S. Pat. No. 4,875,380 to Imbert, insertion tool 76 has the advantage of not requiring the use of a radially self-expanding graft. In insertion tool 76, full advantage is taken of the expandable property of angioplasty balloon 78. In its inflated condition, this balloon 76 is capable of opening a blood vessel to a diameter through which tool 76 can pass with the application of a reasonable level of axial force. In its deflated condition, balloon 76 is small enough to pass through the central hole in graft 14. Thus, standard graft materials, not having a self-expanding characteristic, can be used for graft 14, and the complexity included in the Wallsten et al design, required to deploy a self-expanding graft pushing outward on its covering, is not required.
While the invention has been described in its preferred forms or embodiments with some degree of particularity, it is understood that this description has been given only by way of example and that numerous changes in the details of construction, fabrication and use, including the combination and arrangement of parts, may be made without departing from the spirit and scope of the invention.
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A tool for the intraluminal insertion and deployment of a tubular graft within a blood vessel includes a flexible insertion shaft with a tapered distal end, a tubular sheath, a deployment slider and a safety locking tube. The deployment slider and the graft are slideably mounted, end to end, on a cylindrical portion of the shaft. A tubular sheath, which is slideably mounted to cover the graft and a distal portion of the deployment slider, includes a tapered distal end portion with tabs extending into a circumferential groove in the shaft. The graft is deployed, or released, by first removing the safety lock tube and then the tubular sheath is withdrawn over the proximal end of the shaft, exposing the graft from the outside and from the distal end of the tool. Then the shaft is then withdrawn as the deployment slider is held in place to prevent the withdrawal of the graft. Prior to deployment, the safety locking tube is locked on the proximal end of the shaft in an end to end relationship with the tubular sheath, thereby preventing premature deployment by preventing the withdrawal of the tubular sheath. An alternative version of the tool includes an electrical heating element to aid in the softening and dilating of tissues, and a second alternative version of the tool includes an angioplasty balloon at the distal end, so that obstructions can be cleared by angioplasty as the tool is advanced along a blood vessel.
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FIELD OF THE INVENTION
[0001] The present invention is directed towards the production of nonwovens and concerns associated therewith, in particular, air flow and static electricity.
BACKGROUND OF THE INVENTION
[0002] There presently exists apparatus for the production of nonwovens for example, spun-bond webs, structures or articles formed from filaments or fibers typically made from a thermoplastic resin. Such an apparatus is disclosed in U.S. Pat. No. 5,814,349 issued Sep. 29, 1998, the disclosure of which is incorporated herein by reference. These typically include a spinneret for producing a curtain of strands and a process-air blower for blowing process air onto the curtain of strands for cooling the same to form thermoplastic filaments. The thermoplastic filaments are then typically, aerodynamically entrained by the process air for aerodynamic stretching of the themoplastic filaments which are then, after passing through a diffuser, deposited upon a continuously circulating sieve belt for collecting the interentangled filaments and forming a web thereon. The web, structure or article, so formed, is then transferred and subject to further processing.
[0003] Apparatus of the type aforementioned, particularly for high-speed melt-bond web production are currently available from Reifenhauser GmbH Co. Maschinenfabrik, Spicher Strabe D-53839 Troisdort, Germany and sold under the name Reicofil®. The latest generation of such high-speed spun-bond lines is referred to as the Reicofil® 3 type system.
[0004] Another manufacturer of such equipment is Nordson Corporation, 28601 Clemens Road, Westlake, Ohio 44145. Other manufacturers are STP Impianti, Rieter Perfojet, Kobelco, Ason and NWT.
[0005] An airlaid process may also be used to form a non-woven web. The airlaid process begins with a defibration system to open fluff pulp. A conventional fiberizer or other shredding device may also be used to form discrete fibers. Particles of absorbent materials (for example super absorbent powder), abrasives or other materials may then be mixed with the fibers. The mixture is then suspended in an air stream within a forming system and deposited to a moving forming wire, screen or rotating perforated cylinder. The randomly oriented airformed fiber may then be bonded by applying a latex binder and drying, thermally bonding thermoplastic staple fibers in the web, hydrogen or embossed bonding or a combination thereof.
[0006] In addition, the nonwoven web may be optionally compacted before the bonding step noted above. Compaction is typically performed on the forming wire before bonding. During compaction, the absorbents, abrasives or other materials, which are mixed with the fiber, damage the forming wire. A felt may be used on this position during the compaction step to prevent damage to the forming wire. The compressibility of the felt allows the nonwoven web to compact without damaging the felt or the wire.
[0007] There are a number of commercial processes available to produce airlaid nonwoven webs. For example, airlaid processes are available from Dan-Web Corp. having offices in Risskov, Denmark, and from M&J Forming Technologies having offices in Horsens, Denmark.
[0008] The present invention relates to producing nonwovens and the concerns associated therewith, in particular, static electricity.
[0009] In a nonwovens process, there is a large amount of static electricity generated. The present invention relates to addressing this problem. Normally a negative charge builds up on the filaments or fibers as they are being processed. Successive layers of fibers, since they are the same polarity, tend to repel each other. Charged fibers tend to cling to the press rolls. They also tend to be repelled from the forming fabric, since it will develop a charge thereon during the processing of the charged fibers. This charge tends to accumulate.
[0010] In European Patent Application No. EP 0 950 744 A1 it proposes using press rolls having a dielectric surface which is charged with a polarity that will repel the fibers. The forming fabric is also made from a dielectric material and charged such that it is opposite to that of the fibers, thereby attracting the fibers thereto.
[0011] The present invention concerns dissipating static electric charge whilst maintaining air permeability of a transfer belt. Heretofore, U.S. Pat. No. 4,428,736 proposed dissipating the static charge that is built up by a dryer fabric, thereby preventing adhesion of the paper to the fabric when it is transferred from one fabric to another.
[0012] U.S. Pat. No. 4,541,895 is a PM fabric made up of a plurality of impervious non-woven sheets joined together in a laminated arrangement. Each of the layers serves a particular purpose such as resistance to static charge. In addition, yarns could be incorporated between the laminates to add anti-static properties.
[0013] U.S. Pat. No. 6,001,749 provides a patterned conductive textile by applying a finish to selective parts of a fabric which inhibits the formation of a conductive polymer coating in those areas.
[0014] U.S. Pat. No. 6,153,124 is an electrically conductive knitted fabric made of 2-30 percent by weight of a conductor yarn. The conductor yarn is made of 5-30 percent by weight of galvanized iron fiber and 70-95 percent by weight of a polyester fiber. The conductivity is proportional to the concentration of the yarn.
[0015] None of the prior art however provides for an antistatic transfer belt for use in the production of nonwovens having a woven or spiral formed base to which a conductive batt, foam or other material is added whilst maintaining a desired air permeability.
SUMMARY OF THE INVENTION
[0016] It is therefore a principal object of the invention to provide a transfer belt for the production of non-woven webs, structures or articles, which dissipates static electric charge.
[0017] It is a further object of the invention that an adequate air permeability of the antistatic transfer belt is maintained.
[0018] These and other objects and advantages are achieved by the present invention. In this regard the invention is directed towards generally a transfer belt for use in the production of non-woven webs, structure or articles. So as to address the static electricity problem, the transfer belt may include a conductive material which allows the dissipation of the static electric charge on the web whilst maintaining the desired permeability of the belt.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Thus by the present invention, its objects and advantages will be realized, the description of which should be taken in conjunction with the drawings wherein:
[0020] FIG. 1 is a schematic representation of an apparatus wherein a non-woven web, structure or article is transferred; and
[0021] FIG. 2 is an enlarged sectional view of the transfer belt of the present invention taken along the machine direction of the belt.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0022] Turning now more particularly to the figures where like elements will be similarly numbered, FIG. 1 shows schematically a part of an apparatus 10 for producing a non-woven web 12 by a process other than weaving, for example, by airlaid, drylaid, or spunlace processes. During the transfer of the web 12 before handling from a first position 14 to a second position 16 , a large amount of static electric charge is built up on the web 12 and the transfer belt 18 , which is undesirable. Related to this concern is the need for the transfer belt 18 to be permeable to air drawn through a vacuum system 19 that assists with the transfer of the web 12 .
[0023] Advantageously, the present invention is a transfer belt for use in a nonwovens process which dissipates the static electric charge, whilst maintaining the desired air permeability. In this regard, shown in FIG. 2 is a cross section of the antistatic transfer belt 18 used in the present invention. The transfer belt 18 comprises a base substrate or structure 20 made from a woven or spiral polymer material (which itself can be conductive) or of other construction suitable for the purpose covered with an electrically conductive batt, foam or other material 22 able to maintain air permeability in the range of approximately 20 to 200 CFM, or higher when the belt is coated, while having a low resistivity in the range of 10 0 ohm/square to 10 8 ohm/square.
[0024] The base substrate may be any one of the structures used as bases for paper machine clothing, such as, for example, a woven or a spiral-link fabric. The base substrate may also be assembled from a strip of one of woven materials spirally wound in a plurality of turns, each turn being joined to those adjacent thereto by a continuous seam which is disclosed in commonly assigned U.S. Pat. No. 5,360,656 to Rexfelt et al., the teachings of which are incorporated herein by reference. Further, the base substrate may be woven endless, or flat woven and subsequently rendered into endless form with a woven seam.
[0025] The base substrate may also be a laminated structure comprising two or more base substrates, each of which may be one of the structures described above. Where the base substrate is laminated, one of the component base substrates may be an on-machine-seamable fabric, so that the belt may be seamed into endless form during installation on a paper machine.
[0026] The base substrate may be woven, or otherwise assembled, from yarns of any of the varieties used in the manufacture of paper machine clothing and industrial process fabrics. That is to say, the base substrate may include monofilament, plied monofilament, multifilament, plied multifilament or yarns spun from staple-fibers of any of the synthetic polymeric resins used by those skilled in the art.
[0027] In the example shown in FIG. 2 , the substrate 20 imparts dimensional stability and compressibility to the belt 18 ; the conductive batt, foam or other material 22 dissipates the static electricity from the web 12 to the ground through the belt 18 . Note that the substrate 20 may be joined to the batt, foam or other material 22 by needling, thermal bonding, stitching, chemical process, or other means suitable for the purpose.
[0028] In addition, the conductive material 22 may be coating on base substrate or structure 20 . The coated conductive material 22 may be applied to the base substrate or structure 20 by spraying, extruding, or being a layer of thermofusible material.
[0029] As a further advantage, the web-facing surface of the batt, foam or other material 22 is smooth in order to avoid plugging and marking problems associated with certain nonwovens production utilizing a large amount of what is commonly referred to as Super Absorbent Powder or SAP. For example, the surface of a coated conductive material 22 may be made to obtain the desired surface topography or smoothness by compacting or sanding.
[0030] Accordingly, the antistatic transfer belt 18 of the present invention is a multi-layer structure which may contain one or more bases 20 and one or more layers of batt, foam or other material 22 , a portion of which is conductive. Such a transfer belt 18 reduces static electric charge during nonwovens production whilst providing a desired air permeability in the web production process.
[0031] Although a preferred embodiment has been disclosed and described in detail herein, its scope should not be limited thereby; rather its scope should be determined by that of the appended claims.
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In an apparatus for the production of a nonwoven web, structure, or article using a nonwovens process in combination with a transfer belt which includes conductive material so as to dissipate static electric charge whilst maintaining a desired air permeability;
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FIELD OF THE INVENTION
[0001] The present invention relates to a shroud supporting structure for a gas turbine engine, in which: an annular shroud surrounding tip ends of a plurality of turbine blades which are attached to a turbine disk in a radial arrangement is fitted on an inner peripheral surface of an open end of a turbine case; and a retaining ring fitted on an outer peripheral surface of the open end of the turbine case has a retaining part provided thereon to prevent the shroud from being dropped off in an axial direction.
DESCRIPTION OF THE RELATED ART
[0002] Such a shroud supporting structure for a gas turbine engine is known from Japanese Patent Application Laid-open No. 2001-303907. This invention has a configuration in which the shroud is divided into eight parts in the circumferential direction and is fitted on the inner peripheral surface of the turbine case, and in this state, the retaining ring fitted on the outer periphery of the turbine case is connected to the turbine case with eight rivets; and thereby the retaining part of the retaining ring is placed in engagement with the front end of the shroud, so that the shroud is prevented from dropping off from the turbine case.
[0003] Meanwhile, the above conventional configuration has the following problem: since the retaining ring is connected to the turbine case with the rivets, when the retaining ring is to be attached/detached at the time of assembling or doing maintenance on the gas turbine engine, the work to hammer or cut the rivets is necessary, thereby requiring a lot of time and labor for this work.
SUMMARY OF THE INVENTION
[0004] The present invention has been made in view of the foregoing situation, and an object thereof is to enhance attachment/detachment capability of a retaining ring retaining a shroud for a gas turbine engine to a turbine case.
[0005] In order to achieve the object, according to the present invention, there is provided a shroud supporting structure for a gas turbine engine, in which: an annular shroud surrounding tip ends of a plurality of turbine blades which are attached to a turbine disk in a radial arrangement is fitted on an inner peripheral surface of an open end of a turbine case; and a retaining ring fitted on an outer peripheral surface of the open end of the turbine case has a retaining part provided thereon to prevent the shroud from being dropped off in an axial direction, characterized in that an annular groove formed in the outer peripheral surface of the turbine case and an annular groove formed in an inner peripheral surface of the retaining ring are opposed to each other, and a connection wire is inserted so as to straddle both of the annular grooves, thereby connecting the retaining ring to the turbine case.
[0006] According to the above configuration, the annular shroud which surrounds the tip ends of the turbine blades is fitted on the inner peripheral surface of the open end of the turbine case; and, in order to prevent the shroud from being dropped off in the axial direction by the retaining part provided on the retaining ring fitted on the outer peripheral surface of the open end of the turbine case, the annular groove formed in the outer peripheral surface of the turbine case and the annular groove formed in the inner peripheral surface of the retaining ring are opposed to each other, and the connection wire is inserted so as to straddle the two annular grooves, thereby connecting the retaining ring to the turbine case. Accordingly, it is possible to easily perform attachment/detachment of the retaining ring with respect to the turbine case only by inserting the connection wire into or pulling it out from the two annular grooves, thereby improving ease of attachment/detachment of the shroud and the turbine blades.
[0007] The above description, other objects, characteristics and advantages of the present invention will be clear from detailed descriptions which will be provided for the preferred embodiment referring to the attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] Attached drawings show an embodiment of the present invention:
[0009] FIG. 1 is a longitudinal cross-sectional view of a part of a gas turbine engine showing a neighboring portion of a turbine blade;
[0010] FIG. 2 is a sectional view taken along a line 2 - 2 in FIG. 1 ;
[0011] FIG. 3 is a view seen from a direction of an arrow 3 in FIG. 2 ;
[0012] FIG. 4 is a sectional view taken along a line 4 - 4 in FIG. 3 ;
[0013] FIG. 5 is a sectional view taken along a line 5 - 5 in FIG. 3 ;
[0014] FIG. 6 is a sectional view taken along a line 6 - 6 in FIG. 3 ; and
[0015] FIG. 7 is a perspective view of a connection wire.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0016] An embodiment of the present invention will be described below based on FIG. 1 to FIG. 7 .
[0017] As shown in FIG. 1 , an axial-flow type gas turbine engine includes a turbine disk 11 fixed to a turbine shaft, which is not illustrated, and a plurality of turbine blades 12 are supported in a radial arrangement on an outer periphery of the turbine disk 11 via an attachment part 12 a. A nozzle 13 in which combustion gas from a combustor, which is not illustrated, flows is disposed on an upstream side (left side in the drawing) of the turbine blade 12 . The nozzle 13 is formed of an annular shape having an outer peripheral wall 13 a and an inner peripheral wall 13 b, and a downstream end of the nozzle 13 faces a front surface of a main part 12 b of the turbine blade 12 . The outer peripheral wall 13 a and the inner peripheral wall 13 b of the nozzle 13 are connected by a plurality of stator vanes 13 c which are disposed in a radial arrangement. An exhaust passage 14 disposed on a downstream side (right side in the drawing) of the turbine blade 12 is formed of an annular shape having an outer peripheral wall 14 a and an inner peripheral wall 14 b, and an upstream end of the exhaust passage 14 faces a rear surface of the main part 12 b of the turbine blade 12 .
[0018] A shroud 15 which faces a tip end (outer end in a radial direction) of the turbine blade 12 with a slight gap g interposed therebetween is disposed so as to close a space interposed between the outer peripheral wall 13 a of the nozzle 13 and the outer peripheral wall 14 a of the exhaust passage 14 . A tubular turbine case 16 covering an outer periphery of the exhaust passage 14 and extending toward the front (left side in the drawing) surrounds an outer periphery of the shroud 15 , and an open end of the turbine case 16 and a front end of the shroud 15 are covered by an integrally formed annular retaining ring 17 . A sealing member 19 is supported in an annular groove 13 d provided in a projecting manner on the outer peripheral surface of the outer peripheral wall 13 a of the nozzle 13 for sealing a space between an inner peripheral surface of a front part of the retaining ring 17 and the annular groove 13 d, and a sealing member 20 is supported in an annular groove 14 c provided in a projecting manner on the outer peripheral surface of the outer peripheral wall 14 a of the exhaust passage 14 for sealing a space between an inner peripheral surface of the turbine case 16 and the annular groove 14 c.
[0019] Next, referring to FIG. 2 to FIG. 7 together, a structure of the shroud 15 and a structure for supporting the shroud 15 to the turbine case 16 with the retaining ring 17 will be explained.
[0020] As is clear from FIG. 1 and FIG. 2 , the shroud 15 disposed annularly with an axis L of the gas turbine engine being a center is configured such that eight segments 21 of the same structure each having a center angle of 45° are connected in a circumferential direction. Here, adjacent segments 21 simply abut each other and have no special connecting structure, and the shroud 15 is retained annularly by the turbine case 16 being engaged with the retaining ring 17 .
[0021] The segment 21 of the shroud 15 comprises a shroud main body 22 curved in a circular arc shape, a first flange 23 rising from a front end of the shroud main body 22 outward in the radial direction, and a second flange 24 rising from a rear end of the shroud main body 22 outward in the radial direction. A width in the radial direction of the first flange 23 is formed to be larger than a width in the radial direction of the second flange 24 . A part of the segment 21 which is exposed to combustion gas, that is, a radially inner surface of the shroud main body 22 , and a part of a front surface of the first flange 23 are covered by a liner 25 having a heat resistance.
[0022] On a radially outer end of the first flange 23 of each of the segments 21 , a first engaging part 23 a protruding rearward is formed over its entire length. On a radially outer end of the second flange 24 of the segment 21 , a second engaging part 24 a protruding rearward is formed over its entire length.
[0023] An annular first engaged part 16 a opened toward the front and an annular second engaged part 16 b formed at a position radially inward and rearward of the first engaged part 16 a and opened toward the front are formed in the inner peripheral surface of the turbine case 16 . The first engaging part 23 a and the second engaging part 24 a of each segment 21 of the shroud 15 are engaged, from the front, with the first engaged part 16 a and the second engaged part 16 b of the turbine case 16 , respectively.
[0024] The retaining ring 17 fitted, from the front, on an outer peripheral surface of a front end of the turbine case 16 has an annular groove 17 a of a rectangular section formed in the inner peripheral surface of a rear end thereof. An annular groove 16 c of a rectangular section facing this annular groove 17 a is formed in the outer peripheral surface of the front end of the turbine case 16 . And both of the annular grooves 17 a, 16 c form a square section in cooperation with each other and are engaged with a connection wire 26 having flexibility and a circular section, so that the retaining ring 17 is fixed so as not to drop off from the turbine case 16 to the front side. In a state in which the retaining ring 17 is connected to the turbine case 16 , a retaining part 17 e provided, in a protruding manner, radially inward on the inner peripheral surface of the retaining ring 17 is engaged with a front surface of the first flange 23 of the shroud 15 , so that the shroud 15 is retained so as not to drop off from the turbine case 16 to the front side.
[0025] As is clear from FIG. 3 and FIG. 5 , a recess 16 d depressed radially inward is formed in a part of the turbine case 16 which faces a cutout 17 b formed in a rear edge of the retaining ring 17 and extending in the peripheral direction. The annular groove 16 c of the turbine case 16 and the annular groove 17 a of the retaining ring 17 are opened in an end of the cutout 17 b of the retaining ring 17 .
[0026] As is clear from FIG. 3 and FIG. 6 , a rotation-preventing pin 27 is engaged with a pin hole 17 c formed in the retaining ring 17 in the vicinity of the other end of the cutout 17 b and a pin hole 16 e formed in the turbine case 16 , so that the retaining ring 17 is restrained against rotation relative to the turbine case 16 .
[0027] As is clear from FIG. 3 and FIG. 7 , the connection wire 26 is formed by curving a wire having an elasticity to form an annular shape over substantially 360°, and includes a small-loop-shaped grip part 26 a at one end thereof and a retaining part 26 b curved so as to continue with the grip part 26 a. And the retaining ring 17 includes a recess 17 d which is formed in an end edge thereof adjacent to the cutout 17 b, with which recess the retaining part 26 b of the connection wire 26 can be engaged.
[0028] Next, operations of the embodiment of the present invention having the above configuration will be explained.
[0029] When the shroud 15 and the retaining ring 17 are assembled to the turbine case 16 , the eight divided segments 21 of the shroud 15 are moved from the front to the rear in FIG. 1 (left side to right side in the drawing); and the first engaging part 23 a formed on the first flange 23 of each segment 21 is engaged with the first engaged part 16 a of the turbine case 16 and, concurrently, the second engaging part 24 a formed on the second flange 24 of each segment 21 is engaged with the second engaged part 16 b of the turbine case 16 . Accordingly, the eight segments 21 are integrally connected together, thereby forming the annular shroud 15 .
[0030] Next, in a state in which the retaining ring 17 is fitted on the open end of the turbine case 16 , the retaining ring 17 is positioned in the rotational direction so as to place the pin hole 17 c of the retaining ring 17 in alignment with the pin hole 16 e of the turbine case 16 , and the positioning pin 27 is inserted into both of the pin holes 17 c, 16 e . Subsequently, while elastically deforming the annular connection wire 26 into an elongated state, a tip end of the connection wire 26 on a side opposite from the grip part 26 a is inserted from the cutout 17 b of the retaining ring 17 into both of the annular grooves 16 c , 17 a opened in the recess 16 d of the turbine case 16 . As a result, the connection wire 26 is fitted, over substantially 360°, on both of the annular grooves 16 c, 17 a, and, finally, the retaining part 26 b provided continuously with the grip part 26 a is engaged with the recess 17 d of the retaining ring 17 , so that the grip part 26 a is housed in the recess 16 d of the turbine case 16 (see FIG. 3 ).
[0031] In this state, as shown in FIG. 4 , the connection wire 26 is engaged so as to straddle both of the annular groove 17 a of the retaining ring 17 and the annular groove 16 c of the turbine case 16 . Accordingly, the retaining ring 17 is connected to the turbine case 16 , and the shroud 15 is prevented from dropping off form the inside of the turbine case 16 to the front side by the engaging part 17 e of the retaining ring 17 .
[0032] When the retaining ring 17 is to be separated from the turbine case 16 , only the following work is required: the grip 26 a of the connection wire 26 within the recess 16 d of the turbine case 16 is gripped and pulled; and the entire connection wire 26 is pulled out from the annular groove 17 a of the retaining ring 17 and the annular groove 16 c of the turbine case 16 . And, when the retaining ring 17 is separated from the turbine case 16 , the shroud 15 can be freely attached to or detached from the open end of the turbine case 16 , thereby improving the assemblability and ease of maintenance of the shroud 15 . Further, since the shroud 15 can be fixed to the turbine case 16 only by the retaining function of the retaining ring 17 , any special fixing member is not required, thereby reducing number of parts and cost.
[0033] One embodiment of the present invention is explained above, but the present invention may be modified in a variety of ways as long as the modifications do not depart from the gist of the present invention.
[0034] For example, in the embodiment, the shroud 15 is divided into eight segments 21 , but the divided number is arbitrary.
[0035] Further, in the embodiment, when the eight segments 21 of the shroud 15 is assembled to the turbine case 16 , the first and second engaging parts 23 a, 24 a of the segments 21 are engaged with the first and second engaged parts 16 a, 16 b of the turbine case 16 , but it is possible to employ other arbitrary assembling structure.
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An annular shroud surrounding tip ends of turbine blades is fitted on an inner peripheral surface of an open end of a turbine case. In order to prevent the shroud from being dropped off in an axial direction by a retaining part provided on a retaining ring fitted on an outer peripheral surface of the open end of the turbine case, an annular groove formed in the outer peripheral surface of the turbine case and an annular groove formed in an inner peripheral surface of the retaining ring are opposed to each other, and a connection wire is inserted so as to straddle the two annular grooves, thereby connecting the retaining ring to the turbine case. Accordingly, it is possible to easily perform attachment/detachment of the retaining ring with respect to the turbine case only by inserting the connection wire into or pulling it out from the two annular grooves, thereby facilitating maintenance of the shroud and the turbine blades. Therefore, this can improve ease of attachment/detachment of the retaining ring retaining the shroud of a gas turbine engine to the turbine case.
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BACKGROUND OF THE INVENTION
This invention relates to apparatus of the type disclosed in U.S. Pat. No. 3,466,808 for reconditioning by finishing and "trueing" large diameter, loadbearing circular supports such as the kiln rings, or "tires," which are affixed to and rotatably support rotary kilns and driers used principally in the manufacture of cement.
Tubular rotary kilns commonly of three to four hundred feet in length and ten to twenty or more feet in diameter are used in the manufacture of cement and pulverized lime from limestone and clay. Such long rotary kilns are relatively flexible and have kiln rings, or riding rings affixed thereto of hardened steel machined to close tolerances and several inches thick and several feet in axial length disposed about the periphery of the kiln at spaced distances of forty to sixty feet, for example. The kiln rings are supported and rotate on trunnion roller mountings. Such relatively flexible kilns are heated to high temperatures and continuously rotated over long periods of time and do not necessarily rotate about a fixed central axis since over extended periods of use the kiln rings wear irregularly and may exhibit excessive wear which appears as pitting of the surfaces of the kiln rings or as a deviation of the axial surface from flatness. Replacement of the kiln rings necessitates shutting down the kiln for several weeks with the resulting expensive loss of use of the kiln in addition to the high cost of replacing the kiln rings. In order to avoid deterioration of the kiln rings to the point that they and the trunnion rollers must be replaced, it is common practice to grind the surfaces of the kiln rings until their axial profile is again flat.
Such grinding takes place wile th kiln is in operation and rotating. Both grinding wheels, such as disclosed in U.S. Pat. No. 3,466,808, and grinding belts have been used to recondition the kiln rings. The grinder of prior art apparatus typically was rigidly mounted on a stationary support near the kiln. Usually the kiln ring surface will not follow a uniformly circular path with respect to the stationary grinder. In one instance the kiln ring may wear into an oval profile; in another, the kiln ring may undergo translation movement off of and back onto its supporting trunnion rollers; and in still another, the kiln ring may exhibit large surface profile changes such as bumps, grooves, cavities and flat spots.
In order to maintain uniform grinding, the grinder must be capable of translational movement in a direction radial of the kiln ring to follow changes in the path of the kiln ring surface. Non-uniform grinding could change the circumferential profile of the kiln ring, whereas the grinding is only intended to flatten the axial profile of the ring. Further, inability of the grinder to be translated in a direction radial of the ring in compliance with the surface of the ring could create excessive forces between kiln ring and grinder which might damage ring and/or grinder.
In order to assure compliance of the grinder to the kiln ring surface, it is known in the prior art to use springs to urge the grinder toward the kiln ring. Further, aforementioned U.S. Pat. No. 3,466,898 discloses a combination of mechanical support points on the kiln ring itself together with means permitting limited movement of the grinder relative to the kiln ring while the weight of the grinder is exerted on the kiln ring for the purpose of assuring compliance of the grinder to the kiln ring surface. In such prior art apparatus, control of grinding uniformity is maintained by manual adjustments to the grinder supports to hold a constant grinding pressure.
SUMMARY OF THE INVENTION
It is an object of the invention to provide improved apparatus for uniformly grinding the peripheral surface of a rotating circular member which maintains a constant rate of grinding while still allowing the grinder to move toward and away from the peripheral surface in compliance with change in position of such peripheral surface relative to the grinder or of changes of profile of the peripheral surface.
In accordance with this and other objects of the invention, there is provided a grinder; means including an electrical motor for continually driving the grinder; pneumatic cylinder means for urging the grinder against the peripheral surface of the rotating circular member with a force proportional to the pressure of fluid supplied to the pneumatic cylinder; and means for maintaining the pressure of the fluid within the pneumatic cylinder tending to urge the grinder against the peripheral surface substantially constant regardless of changes of relative position between the peripheral surface and the grinder tending to change the grinding load on the grinder. As external forces such as a raised spot on the kiln ring or translational movement of the kiln ring toward or away from the grinder attempt to change the load on the grinder, the control responds to counteract such tendency by manipulating the fluid pressure within the pneumatic cylinder in a direction to maintain constant grinding load. In a preferred embodiment, means for maintaining the fluid pressure within the pneumatic cylinder substantially constant regardless of external forces tending to change grinder load includes a current transformer for sensing the magnitude of current flow to the motor, means for selectively establishing a set point reference of desired current flow to the motor and pressurized fluid source means for comparing the set point reference to the current sensed by the current transformer and for supplying fluid to the pneumatic cylinder at a pressure which will maintain the current flow to the motor equal to the set point reference.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other objects and advantages of the invention will be more readily apparent from the following detailed description when considered with the accompanying drawing wherein:
FIG. 1 is a side view of kiln ring, grinder, and grinder motor which schematically illustrates a preferred embodiment of the invention having a pneumatic cylinder for maintaining the grinder in compliance with the kiln ring surface and means for maintaining the pneumatic cylinder pressure substantially constant regardless of changes in grinding load to thereby assure uniform grinding of the kiln ring surface;
FIG. 2 is a top view of the FIG. 1 apparatus;
FIG. 3 is a side view of an alternative embodiment of the invention wherein the pneumatic cylinder pulls downward on the grinder to maintain it in compliance with the kiln ring surface;
FIG. 4 is a graph plotting sensed motor current input to converter I/P versus output pneumatic pressure;
FIG. 5 is a schematic representation of the pressure and current controller which receives as one input the output from converter I/P that is proportional to the magnitude of sensed grinding motor current and as a reference input the set point desired motor current and supplies as an output pressurized air to the pneumatic cylinder at a pressure which is a function the difference between the sensed current and set point reference inputs to maintain motor current at the set point value; and
FIG. 6 is a graph plotting motor current versus motor load.
DETAILED DESCRIPTION
The drawings do not disclose the huge size of the rotary kiln 10 and do not show the trunnion rollers which rotatably support it but do illustrate in side view one of the kiln rings 11 which is affixed to the kiln 10 and is rotatably supported upon such trunnion rollers as kiln ring 11 is being reconditioned by a belt grinder 12 while the rotary kiln 10 is in operation. As described hereinbefore, such tubular rotary kilns 10 are commonly of three to four hundred feet in length and ten to twenty or more feet in diameter and are relatively flexible and the kiln rings 11 affixed thereto are of hardened steel several inches thick and several feet in axial length disposed about the periphery of the kiln 10 at spaced distances of forty to sixty feet, for example. Such relatively flexible rotary kilns 10 may be lined with refractory brick 13 and heated to high temperature and continuously rotated over long periods of time and do not necessarily rotate about a fixed central axis since over extended periods of use the kiln rings 11 wear irregularly and may exhibit excessive wear which appears as pitting of the peripheral surface of the ring 11 or as a deviation of its axial surface from flatness.
Our invention achieves compliance of the belt grinder 12 to the surface of the kiln ring 11 by means of a pneumatic cylinder 14 to produce the force required to urge grinder 12 against the peripheral surface of the kiln ring 11 and cause uniform grinding as belt grinder 12 is continuously driven by a grinding motor 15, preferably of the electric type. Pneumatic cylinder 14 is shown in FIG. 1 as a single-ended cylinder wherein pneumatic pressure is applied to only one fixed end of the cylinder casing and the other end is vented to the atmosphere. Cylinder 14 may be mounted on an upper slide carriage 16 which is dovetailed on a lower slide carriage 17 to permit translational movement of upper carriage 16 carrying grinder 12 toward and away from kiln ring 11 by, for example, turning of handle 18 which rotates a feed screw 19. Lower slide carriage 17 is dovetailed on a stationary bed member 20 to permit movement of lower and upper carriages 16 and 17 carrying motor 15 and grinder 12 parallel to the axis of kiln ring 11. Means 21 are provided for moving grinder 12 parallel to the axis of, and back and forth across, the peripheral surface of kiln ring 11 while grinder 12 is conditioning such peripheral surface, and such means is illustrated in FIGS. 1 and 2 as a manual handle 22 for rotating a feed screw 23 which engages lower carriage 17. Such means 21 for moving the grinder 12 axially of the kiln ring may comprise a computer controlled drive (not shown) of the type for operating an automatic lathe so that the cutting tool moves back and forth across the surface of the work object.
An upright member 25 mounted on upper carriage 16 has affixed adjacent its upper end a horizontal support arm 26 which is pivotally connected to one end of pneumatic cylinder 14 to permit movement of grinder 12 toward and away from kiln ring 11 in compliance with the kiln ring peripheral surface and to maintain uniformity of grinding of such surface.
It is schematically represented in the drawing that grinder 12 includes an abrasive belt 28 which encircles an upper driven idler drum 29 and a lower driving drum 30 secured to the shaft 31 of grinding motor 15. Upper driven idler drum 29 is journalled on an axle shaft 32 whose ends are rotatable within a pair of shaft support blocks 33 disposed on opposite sides of drum 29. Blocks 33 are slidable within grooves 35 provided adjacent the upper end of a pair of inclined support plates 36 that are disposed on opposite sides of drums 29 and 30 and pivotally mounted at their lower end on motor shaft 31. Belt tensioning adjusting bolts 38 engage internally threaded members 40 affixed to support plates 36, and the ends of bolts 38 bear against slidable blocks 33 so that turning of adjusting bolts 38 increases or decreases the distance between driving drum 30 and idler drum 29, and thus changes the tension in belt 28.
One end of the piston 42 of pneumatic cylinder 14 is attached to a yoke 43 having bifurcated portions secured to support plates 36 on opposite sides of idler drum 29 so that movement of piston 42 can actuate upper drum 29 carrying abrasive belt 28 toward and away from kiln ring 11 as pressure is increased and decreased, respectively, within cylinder 14 to thereby actuate piston 42 to the left and the right as seen in FIG. 1. A return spring 44 disposed within the casing of cylinder 14 reacts at one end against the cylinder casing and at the other end against piston 42 to return the piston and withdraw belt 28 in a direction away from kiln ring 11 when pressure is lowered within pneumatic cylinder 14. It will be readily apparent that return spring 44 can be external of the cylinder casing and that the fluid pressure with cylinder 14, and the resulting force exerted by piston 42, must be sufficiently high to deflect return spring 44 and force belt 28 against the peripheral surface of kiln ring 11.
Pneumatic cylinder 14 preferably is compatible with the normal 3-15 psig pneumatic control range. Inasmuch as the air within pneumatic cylinder 14 is compressible, movement of kiln ring 11 toward grinder 12 can move the grinder 12, including belt 28 and driven drum 29, to the right as seen in FIG. 1 without causing high mechanical forces on grinder 12 or the kiln ring 11. The only result of such movement of kiln ring 11 toward or away from grinder 12 is that the pressure within pneumatic cylinder 14 increases or decreases from its set point value. If kiln ring 11 does move relative to grinder 12 and changes the pressure within pneumatic cylinder 14, grinder 12 will engage kiln ring 11 with more or less than the desired force and in prior art apparatus would not grind ring 11 at a uniform rate. Our invention prevents such non-uniform grinding by cylinder pressure control means which regulates the pressure within pneumatic cylinder 14 as a function of the magnitude of current to grinding motor 15. Stated in another way, our invention includes pneumatic cylinder input pressure control means which varies the pressure within cylinder 14 so as to maintain the motor current at a constant value.
For example, if kiln ring 11 moves toward grinder 12, it will force driven drum 29 and piston 42 to the right as seen in FIG. 1, thereby compressing the air in cylinder 14 and raising its pressure. Such increased pressure will increase the force of grinder 12 against the surface of kiln ring 11, thereby increasing the grinding rate and drawing higher current to grinder motor 15. The cylinder input pressure control means of the invention senses that the motor current is above the set point value and automatically reduces pressure within cylinder 14 until the motor current, and hence the grinding rate, is again at the set value. On the other hand, if kiln ring 11 moves away from grinder 12, the cylinder pressure control means automatically increases the pressure within cylinder 14 to maintain uniform motor current and a uniform grinding rate of kiln ring 11.
Current from an electric power line flows through a circuit breaker 45 to motor 15 and the magnitude thereof is sensed by a current transformer CT and is an input through an optional ammeter 46 to a current-to-pressure converter I/P. Converter I/P also has an input from a constant pressure compressed air supply 47, e.g., 20 psig, and produces an output pneumatic pressure on fluid line MV shown in FIG. 4 ranging from 3 to 15 psig as the motor input current sensed by current transformer CT changes over the range from zero to five amperes rms. Current transformer CT may have a standard five ampere secondary and its primary current rating will be determined by the range of motor current with sufficiently wide operating limits to handle inrush starting current to motor 15.
Grinder 12 may alternatively be a grinding wheel. Further, grinding belt 28 need not be driven directly by an electric motor 15, but rather could be driven by a hydraulic motor (not shown) or an air motor. In such alternative embodiments, current transformer CT could sense the current to the electric motor which drives the hydraulic pump supplying the hydraulic or the air motor. Alternatively, current sensing could be changed to pressure sensing in the hydraulic motor power hose since, given constant hydraulic flow, pressure sensing would measure grinder power.
The pneumatic pressure output from converter I/P is an input (over a fluid line designated ) to the measured variable MV input of a controller P&I which also has a 20 psig compressed air supply input 47. Controller P&I may be a Moore 55 Controller commercially available from Moore Products Company of Spring House, Pa. The compressed air output P o from controller P&I is fed over a fluid line (also designated by the symbol ) to pneumatic cylinder 14 and is in a direction to change the pressure to pneumatic cylinder 14 until the current to motor 15 is at the set point value, and hence the grinding rate is at the desired value.
The schematic circuit of controller P&I is shown in FIG. 5 and its operation follows the classic controller equation: ##EQU1## The pneumatic signal from converter I/P (which is proportional to measured motor current) serves as the measured variable fed into the MV(-) input of summing junction 50 of controller P&I, which controller also receives three other adjustment inputs, namely:
(1) SP=set point and is the desired motor current expressed in psig fed into a second (+) input of summing junction 50 so that the output thereof on line 51 is proportional to (SP-MV). This set point adjustment SP establishes a reference pressure against which the MV input pressure is measured;
(2) PB=proportional band (dial setting) and is the "proportional band" adjustment on the controller expressed as percent of the linear range. For example, if the linear range is from 3-15 psig, or 12 psig total, a 10% PB setting would require a 1.2 psig input change on lead MV to cause a full range output swing P o of 12 psig. The output (SP-MV) from summing junction 50 appearing on line 51 is an input to a gain setting constant multiplier designated 100/PB which performs the 100/PB{(SP-MV)} multiplication function appearing on line 52 which is applied to a (+) input of summing junction 54. As long as (SP-MV) does not equal zero, a non-zero signal will pass through element 100/PB. If an abrupt change in measured variable MV occurs, it passes directly through summing junction 54 to output P o leading to pneumatic cylinder 14 and also applies an input over line 58 to summing junction 60 of integrator section 56, and the integrator section 56 continues to function until the signal applied to input 62 of summing junction 54 is equal to output P o ; and
(3) MR=minutes per reset (dial marking) and is the minutes per reset adjustment of the integrator section 56 of controller P&I (0.1 seconds minimum). This is equivalent to a time constant of 60×MR seconds. The integrator section 56 of the controller P&I which calculates the ∫(SP-MV) dt equation continually changes the pneumatic pressure output P o as long as SP and MV are unequal; i.e., until (SP-MV)=0, thus forcing equality of the measured value MV (motor current) to set point SP (desired grinder motor current) through the feedback loop (comprising cylinder 14 and motor 15) to within component tolerances and yielding zero error. This is in contrast to a simple linear amplifier which would have a finite error proportional to gain. It should be noted that the "proportional" action 100/PB{(SP-MV)} is not subject to the integrator time constant, thus permitting fast corrective action.
If MV (sensed motor current) is higher than SP, controller P&I will reduce its output pressure P o , which ultimately reduces pressure in pneumatic cylinder 14. This reduces grinding force and motor current until MV and SP are equal. In order to initially set SP, ammeter 36 is observed while grinding and SP is adjusted until ammeter 36 shows that motor current is at the desired value (SP) by automatic action of the controller P&I as it adjusts pneumatic cylinder pressure in the proper direction.
A step increase in the measured variable MV (motor current) produces a step decrease in output pressure P o according to
P.sub.o =100/PB{(SP-MV)}
Integral action occurs with a time constant, adjusting output pressure P o from controller P&I until MV=SP again.
The pneumatic components of the disclosed embodiment are supplied from a 20 psig compressed air source 47 and have a normal operating range of 3-15 psig. Pneumatic cylinder 14 typically operates at higher pressure (up to 60 psig), and consequently amplifying relay 65 may be inserted between controller P&I and pneumatic cylinder 14. A high limit relay 66 may be inserted between controller P&I and pneumatic cylinder 14 to limit the final signal pressure to 15 psig, since in some cases controller P&I output P o can reach the full 20 psig supply value.
FIG. 3 illustrates an alternative embodiment wherein pneumatic cylinder 14 pulls down on grinder 12 to urge it into grinding engagement with kiln ring 11. The lower end of pneumatic cylinder 14 is pivotally connected to an upwardly projecting member 64 on upper carriage 16. During normal operation P o from controller P&I is supplied between piston 42 and the upper end of cylinder 14 while the lower end of cylinder 14 is vented through a two-way valve V to the atmosphere. Valve V is actuated to its alternative position to connect the lower end of cylinder 14 to constant pressurized fluid supply source 47 when it is desired to raise grinder 12 and cease grinding.
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Apparatus for uniformly grinding the peripheral surface of a kiln ring of a rotating rotary kiln to axial flatness includes a grinder; an electrical motor for continually driving the grinder; a pneumatic cylinder for urging the grinder against the surface of the kiln ring; a current transformer for sensing the magnitude of current flow to the motor; and a controller which compares the magnitude of sensed motor current to a set point reference of desired current flow to the motor and supplies pressurized fluid to the pneumatic cylinder at a pressure which varies as an inverse function of the difference between sensed current and set point references and maintains the current flow to the motor equal to the set point reference.
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BACKGROUND OF THE INVENTION
Flexible urine drainage bags, conventionally formed of peripherally sealed vinyl sheets, incorporate, in most instances, an elongate elastomeric outlet tube with a proximal end communicating with the interior of the bag at a low point therein. The distal end of the outlet tube is normally slidably received within a closed-end housing affixed to the bag above the proximal end of the tube.
In order to slidably engage the free distal end of the tube within the housing, the tube is flexed, normally adjacent the bag-engaged proximal end thereof, to align the free tube end with the housing. The received tube end is frictionally retained, both because of a snug engagement of the tube end within the housing and in light of pressure of the received tube end against the housing wall arising from the natural tendency for the tube to straighten or return to its unflexed position.
The distal end portion of the outlet tube is periodically disengaged from its secure "parked" position in the housing for an emptying of the vinyl drainage bag to a suitable drainage container. While the outlet tube is normally provided with a shut-off clamp, the distal end portion of the tube remains free and, upon release from the housing, tends to snap or spring outward due to the resilient nature of the outlet tube. Such a springing action results in an outward flicking or spraying of residual droplets of urine which accumulate within the outlet tube during normal usage of the drainage bag. Thus, the user or health care worker is exposed to such droplets which, not infrequently, fall both on the hands and the face and expose the individual to a great potential for contamination. This problem has become particularly acute in light of the increasing incidence of Acquired Immune Deficiency Syndrome (AIDS) and the increasing concern among health care workers of contamination from the body fluids of patients.
SUMMARY OF THE INVENTION
The principal purpose of the invention is to reduce exposure to urine when manipulating or repositioning the urinary drainage bag outlet tube. The aseptic drainage outlet device of the invention allows an individual to disconnect the outlet tube from its secure parked position without fear of residual droplets of urine being "flicked" on the user's hands or face due to the spring-like action normally resulting from the inherent elastic resiliency of the tube.
This control over the tube is effected utilizing a coupler which includes a connector mounted on the distal or discharge end of the tube, rigidifying the end portion of the tube and forming a rigid hollow cylindrical extension thereof. The connector releasably locks or couples to the bag-mounted housing. Disengagement of the connector from the housing utilizes a positive manual grasping and manipulation of the connector in a manner which, in conjunction with the construction of the connector, both controls and inhibits any tendency for the tube end portion to flick or otherwise resiliently snap as it is withdrawn from the housing.
The coupler connector comprises an elongate hollow cylindrical or tubular body having an inlet end portion frictionally telescoped within the distal end portion of the outlet tube. The connector body further includes a discharge end portion which extends linearly beyond the outlet tube, defining a rigid extension which is selectively received, in a substantially sealed manner, within a bag mounted housing.
The connector is secured to the housing by a pair of longitudinally extending diametrically opposed pivot bars or arms which are integrally pivoted to the connector body at approximately mid-point along the length thereof. The arms include rearwardly extending opposed lever portions which overlie the distal discharge end of the outlet tube whereby a grasping and manipulation of these lever portions also involves a simultaneous gripping of the tube end portion. The arms also include forwardly extending gripping portions which engage to the opposite sides fo the housing upon the insertion of the connector body therein. The gripping portions terminate in laterally inwardly directed rigid fingers which engage behind a shoulder portion about the housing in a manner whereby a radial outward movement of the fingers is required to release the connector for withdrawal from the housing. The bars or arms, in the at-rest or relaxed position thereof, position the fingers for engagement behind the housing shoulder. An outward springing of the gripping portions of the arm is required to both engage and disengage the connector. Upon release of pressure on the arms, the arms, through the inherent memory of the material of the connector, automatically return to the at-rest position.
Polypropylene is a preferred material for the connector due to its ability to be flexed numerous times without distortion, and because of the memory characteristics thereof. This material is also preferred in light of its ability to withstand the heat of sterilization without distortion, and its imperviousness to chemicals used in hospital environments. It is also economical and widely used in injection molding. Another, although more costly, material is ABS.
Other features and advantages of the invention will become more apparent from the more detailed description following hereinafter.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an elevational view of a drainage bag with the tube locking and manipulation system of the invention incorporated therein;
FIG. 2 is an enlarged plan view of the coupling system with the connector tube-mounted and engaged with the housing;
FIG. 3 is a longitudinal sectional view through the structure of FIG. 2 with the connector engaged with the housing;
FIG. 4 is a longitudinal cross-sectional view similar to FIG. 3 with the connector disengaged from the housing;
FIG. 5 is an exploded perspective view of the connector and housing; and
FIG. 6 illustrates a variation of the connector engaged with a conventional housing.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now more specifically to the drawings, reference Numeral 10 is used to designate a conventional flexible urine drainage bag incorporating an elongate elastomeric outlet tube 12 mounted with one end thereof in sealed communication with the low point of the bag 10. The distal or outer discharge end of tube 12 is, in the conventional drainage bag, telescopically received in a substantially sealed manner in a housing affixed to the wall of the bag at a point above the bag-communicating inner or proximal end of the tube.
In the present invention, the distal end portion 14 of the tube 12 mounts a connector 16 which in turn releasably locks to a complementarily configured housing 18 to define a coupling.
The connector, preferably injection molded of polypropylene, includes a substantially rigid hollow cylindrical or tubular body 20.
A pair of elongate rigid bars or arms 22 parallel the body 20 in outwardly spaced relation to diametrically opposed sides of the body 20. Each arm, at an intermediate point along the length thereof, is integrally joined to the body 20 at an intermediate point along the length of the body by a joinder or link 24. The links 24 are sufficiently resilient, in the manner of a living hinge, to allow for a manual pivoting of the arms as suggested in FIG. 4. The arms 22 also possess sufficient elastic memory to return the arms 22, after release of manual pressure, to the position of FIG. 3, paralleling the body 20.
The connector arms 22 are flat members reinforced, on the inner surfaces thereof, by central ribs 26 which, with regard to each arm 22, are provided as an aligned pair tapering outward from a maximum thickness at the intermediate link 24 and terminating adjacent the outer opposed ends of the arm.
The connector body 20 includes a mounting portion 28 rearward of the links 24 which is telescopically received within the discharge end portion 14 of the outlet tube 12. The tube 12 preferably seats directly against the links 24 to ensure a complete mounting of the connector 16. The body also includes a forward or discharge portion 30 which is adapted to engage within the housing 18.
The opposed arms 22 each includes a rearwardly extending lever portion 32 which projects beyond the body portion 28 to define elongate finger grips for manipulation of the arms and to allow for a positive gripping of the outlet tube 12. The arms 22 also include forwardly extending gripping portions 34, each of which terminates in an inwardly directed locking finger or flange 36. The fingers 36 are positioned immediately inward of the extreme forward end of the discharge portion 30 of the body 20.
The housing 18 is preferably formed of PVC and dialectrically sealed to the wall of the bag 10 above and to one side of the point of communication between the tube 12 and the bag. The housing 18 includes an elongate bore or socket 38 therein which tapers rearwardly from an open end 40 to a closed inner end 42. The bore is dimensioned and configured to snugly telescopically receive the discharge portion 30 of the connector body 20 in a generally sealed relationship.
The exterior of the housing 18 tapers rearwardly from the open end 40 of the socket 38 and defines a generally conical housing exterior terminating in a shoulder 44 arcuately about the housing slightly forward of the closed end 42. The conical exterior of the housing 18 forms a ramp-like surface which facilitates an engagement of the connector 16 therewith in that the inwardly directed fingers 36 of the arms 22 will engage and slide along the exterior surface as the connector body 20 is introduced into the socket 38, resulting in a spreading of the gripping portions 34 of the arms 22 against the spring action of the integral links 24 until such time as the fingers 36 pass beyond the shoulders 44. At that point, due to the memory characteristics of the arms 22, the fingers 36 will snap behind the shoulders 44 and lock the connector against withdrawal from the housing until such time as a positive manual release is effected.
Incidently, in order to facilitate the movement of the connector into locked engagement with the housing, it will be noted that the inner ends of the fingers 36, along the forward or leading edges 46 thereof, are slightly beveled. Further, the extension of the discharge portion 30 of the body 20 slightly forward of the fingers 36 facilitates an alignment of this tubular body 20 with the housing socket 38 for telescopic movement therein. It is contemplated that the length of the discharge portion 30 of the connector body 20 be slightly longer than the depth of the housing socket 38 so as to provide for a snug seating of the leading end of the discharge portion 30 at the inner end of the socket 38.
Manual release of the connector requires a firm grasping of the discharge end portion of the tube 12 and a positive finger manipulation of the lever portions 32 of the fingers 22. This, in turn, particularly in conjunction with the rigidity at the discharge end defined by the connector body 20, allows for a withdrawal of the outlet tube 12 without any accidental flipping or snapping of the tube end such as could produce an undesirable and uncontrolled discharge of any residual droplets of urine. The actual drainage of the bag is, in a conventional manner, controlled by an appropriate shut-off clamp (not shown) mounted on the outlet tube 12 intermediate the length thereof. Both the coupler of the present invention and the conventional shut-off clamp can be operated by the same hand of the user, thus leaving the other hand free for positioning a collection receptacle or the like.
Noting FIG. 6, the connector 48 therein differs in that the gripping fingers 50 are formed as inwardly angled bends in the respective arms 52. Each finger is defined by a first portion 54 inwardly angled at approximately 45° to the respective arm 52, and a second portion 56 outwardly angled from the first portion 54 at approximately 90° to define a forwardly directed camming face.
The housing 58 is of substantially conventional shape and includes a slightly flared tube-guiding flange 60 about the open end. The connector 48 can engage with the housing by merely an inward movement of the connector with the angled fingers 50 camming over the flange 60 for engagement therebehind.
The coupler of the invention provides for a positive securement of the outlet tube within the housing against any possibility of accidental, casual or unplanned release during use of the drainage bag. In addition, the coupler, and in particular the connector, encourages a positive manual grasping of the connector within the hand and a manipulation of the gripping means in a specific manner to effect a release of the outlet tube for withdrawal from the housing. Through a continuous engagement of the hand with the substantially rigid connector, the discharge end of the outlet tube is at all times controlled by the user, thus effectively precluding substantially any possibility of a flicking action as commonly experienced in the conventional elastomeric outlet tube without the coupler means of the invention.
While not illustrated, the present invention also contemplates the possibility of the connector being engagable with an appropriate mating drainage tube or receptacle incorporating a tubular end for reception of the discharge portion of the connector body, and shoulder means for releasable engagement of the connector fingers therewith, thereby further reducing contamination potential.
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In a urinary drainage bag, a coupler for the outlet tube including a connector mounted on the discharge end of the outlet tube and defining a rigid extension thereof receivable within a bag-mounted housing. The connector includes spring arms having locking fingers releasably engagable behind a housing shoulder upon a seating of the connector body within the housing. The fingers are selectively released through a manual manipulation of the connector arms which provide for a positive handhold on the connector as the outlet tube is released.
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TECHNICAL FIELD OF THE INVENTION
[0001] The present invention relates to methods and systems for mitigating cyber attacks on industrial control systems.
BACKGROUND
[0002] An Industrial Control System (ICS) includes combinations of control components (e.g., electrical, mechanical, hydraulic, pneumatic) that act together to achieve, an industrial objective (e.g., manufacturing, transportation of matter or energy).
[0003] Many ICS comprise, for example, a number of field sites where industrial objectives are accomplished, together with, for example, a control center which monitors and manages the industrial objective. The control center and field sites are linked via, for example, telecommunications channels or data links. The control center monitors or manages the industrial objective using, for example, industrial control protocols such as DNP3 (Distributed Network Protocol), Modbus, OPC, and the like.
[0004] Attacks by malicious parties on industrial control systems have been an increasing concern. This is because ICS were ‘designed insecure’, with the assumption of air gap between the intranet and the internet. Cyber attacks on ICS have already disrupted critical infrastructure and in the future may cause even more profound damage to facilities, critical services, the environment, and even human life.
SUMMARY OF THE INVENTION
[0005] The present invention provides for mitigation of cyber attacks on ICS as it provides an accurate way of detecting when an attack is underway. Moreover, the present invention effectively responds to a detected attack by taking active steps to halt the intrusion without impacting the operation of crucial industrial infrastructure.
[0006] The following is an exemplary and non-limiting list of threats to modem ICS, which are mitigated by the present invention:
1. Viruses capable of masquerading as a Programmable Logic Controller (PLC) and transmitting traffic in order to cause harm to an ICS system. 2. Code injection into the Human-Machine Interface (HMI) application, by recognizing the profile of the communication within critical infrastructure networks. 3. Exploitation of ICS protocols such as Modbus, DNP3 etc. 4. Malicious activities originating from hosts which do not reside on the operational network. 5. Exploitation of communication protocols, which are not ICS oriented, but are common in operational networks, such as: Hyper Text Transfer Protocol (HTTP), File Transfer Protocol (FTP). Server Message Block (SMB). NetBios. 6. Unauthorized operations being taken by authorized users within the operational network, which are outside the scope of their permitted work.
[0013] The following is an exemplary and non-limiting list of solutions which the invention provides for, which may be attended to by operational and security personnel:
1. A solution for learning the traffic being generated by different PLCs found on the network. An attempt to deviate from these patterns will be detected, 2. A solution for learning the traffic being generated by different HMIs found on the network. An attempt to deviate from these patterns will be detected. This profile includes attempts to perform code injection. 3. A solution of performing traffic analysis according to specifications, i.e., reviewing the traffic being transmitted on the network and validating it according to known specifications. 4. A solution for modeling the behavior of the network as a state machine. This solution can automatically and accurately map the elements operating on the network, and to model their behavior as a finite set of states. It then tracks the behavior of each elements according to the model that was constructed and that is considered as legitimate.
Whenever a malicious actor starts operating on the network, whether inside or outside of the network, the resulting traffic will be detected as violating the state machine's model.
5. A solution for profiling the usage of IT (Information Technology) protocols inside operational environments, as part of the state machine described in item 4. This can be accomplished due to the fact that most of the communications is machine-to-machine based, and therefore very well defined (compared to regular IT networks). 6. A solution for profiling the user behavior inside operational environments, as part of the state machine described above. This can be accomplished due to the fact that a user operating inside an operational network usually has a very well-defined role arid activities (in relation to users in regular IT networks).
[0020] Embodiments of the present invention are directed to a method, which is computer implemented, for detecting a potential compromise of cyber security in an industrial network. The method comprises: establishing a baseline of site-acceptable network behavior comprising a list of network states and transition probabilities, wherein a transition probability denotes an estimated probability of a first network state being followed temporally by a second network state during normal network operation; establishing a threshold representing the probability below which a sequence of network states is anomalous; determining a probability for the occurrence of a sequence of network states as obtained from a particular stream of packets, according to the baseline of site-acceptable network behavior; and, taking protective action according to whether the determined probability is below the established threshold.
[0021] Optionally, the establishing a baseline of site-acceptable network behavior comprising a list of network states and transition probabilities comprises: analyzing a series of packets representing normal network behavior, to determine a temporal sequence of network states; and, computing the probability of a first network state being followed temporally by a second network state, according to the number of times that the first network state is followed temporally by the second network state in the determined temporal sequence of network states.
[0022] Optionally, the particular stream of packets comprises packets received in monitoring the operation of the industrial network for potential cyber attack.
[0023] Optionally, the industrial network utilizes the Modbus protocol.
[0024] Optionally, the industrial network utilizes Distributed Network Protocol 3 (DNP3).
[0025] Optionally, the sequence of network states derived from a particular stream of packets includes “k” successive network states, Where “k” is greater than two.
[0026] Optionally, the taking protective action comprises raising an alert.
[0027] Optionally, the taking protective action comprises blocking a packet.
[0028] Optionally, the taking protective action comprises disabling a node in the network.
[0029] Optionally, the analyzing a series of packets representing normal network behavior, to determine a temporal sequence of network states comprises determining a network state according to the combination of Modbus source, Modbus destination, and Modbus function fields in the analyzed packet.
[0030] Optionally, the alert comprises forensic data.
[0031] Embodiments of the present invention are directed to a computer system to detecting a potential compromise of cyber security in an industrial network. The computer system comprises: a storage medium for storing computer components; and a computerized processor for executing the computer components comprising: a first computer component for establishing a baseline of site-acceptable network behavior comprising a list of network states and transition probabilities, wherein a transition probability denotes an estimated probability of a first network state being followed temporally by a second network state during normal network operation; a second computer component for establishing a threshold representing the probability below which a sequence of network states is anomalous; a third computer component for determining a probability for the occurrence of a sequence of network states as obtained from a particular stream of packets, according to the baseline of site-acceptable network behavior: and, a fourth computer component for taking protective action according to whether the determined probability is below the established threshold.
[0032] Embodiments of the present invention are directed to a computer-usable non-transitory storage medium having a computer program embodied thereon for causing a suitable programmed system to detecting a potential compromise of cyber security in an industrial network, by performing the following steps when such program is executed on the system, the steps comprising: establishing a baseline of site-acceptable network behavior comprising a list of network states and transition probabilities, AA/herein a transition probability denotes an estimated probability of a first network state being followed temporally by a second network state during normal network operation; establishing a threshold representing the probability below which a sequence of network states is anomalous; determining a probability for the occurrence of a sequence of network states as obtained from a particular stream of packets, according to the baseline of site-acceptable network behavior; and, taking protective action according to whether the determined probability is below the established threshold.
[0033] This document references terms that are used consistently or interchangeably herein. These terms, including variations thereof, are as follows:
[0034] A “computer” includes machines, computers and computing or computer systems (for example, physically separate locations or devices), servers, computer and computerized devices, processors, processing systems, computing cores (for example, shared devices), and similar systems, workstations, modules and combinations of the aforementioned. The aforementioned “computer” may be in various types, such as an industrial computer (Remote Terminal Unit (RTU), Intelligent Electronic Device (IED, Programmable Logic Controller (PLC) appliance), a personal computer (e.g., laptop, desktop, tablet computer), or any type of computing device, including mobile devices that can be readily transported from one location to another location (e.g., smartphone, personal digital assistant (PDA), mobile telephone or cellular telephone).
[0035] A “server” is typically a remote computer or remote computer system, or computer program therein, in accordance with the “computer” defined above, that is accessible over a communications medium, such as a communications network or other computer network, including the Internet. A “server” provides services to, or performs functions for, other computer programs (and their users), in the same or other computers. A server may also include a virtual machine, a software based emulation of a computer.
[0036] An “application”, includes executable software, and optionally, any human-machine interfaces (HMI), through which certain functionality may be implemented.
[0037] The term “linked” as used herein includes both wired or wireless links, either direct or indirect, and placing the computers, including, servers, components and the like, in electronic and/or data communications with each other.
[0038] The term “deep packet inspection” as used herein refers to a form of computer network packet filtering that examines the data part (and possibly also the header) of a packet as it passes an inspection point, searching for protocol non-compliance, viruses, spam, intrusions, or the like.
[0039] The term “virtual server” as used herein refers to a server that shares computer resources with other virtual servers i.e. it is not a dedicated server wherein the entire computer is dedicated to running the server software. Virtual servers may exist, for example, as guests in public or private cloud computing deployments.
[0040] The term “big data” refers to a high-data, high-velocity storage which resides, for example, on multiple nodes.
[0041] Unless otherwise defined herein, all technical and/or scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention pertains. Although methods and materials similar or equivalent to those described herein may be used in the practice or testing of embodiments of the invention, exemplary methods and/or materials are described below, In case of conflict, the patent specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and are not intended to be necessarily limiting.
BRIEF DESCRIPTION OF DRAWINGS
[0042] Some embodiments of the present invention are herein described, by way of example only, with reference to the accompanying drawings, With specific reference to the drawings in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of embodiments of the invention. In this regard, the description taken with the drawings makes apparent to those skilled in the art how embodiments of the invention may be practiced.
[0043] Attention is now directed to the drawings, where like reference numerals or characters indicate corresponding or like components. In the drawings:
[0044] FIG. 1 is a diagram illustrating a system environment in which an embodiment of the invention is deployed;
[0045] FIG. 2 is a diagram of the architecture of an exemplary learning and threat detection machine utilizing the invention;
[0046] FIG. 3 is a flow diagram illustrating the logic implemented in the Data Collection Module;
[0047] FIG. 4 is an exemplary protocol-specific vector input to the State Machine Module and optional Scenario-based Alert Module;
[0048] FIG. 5 is a flow diagram of logic implemented in the Scenario-based Alert Module;
[0049] FIG. 6 is an exemplary packet-based scenario data structure;
[0050] FIG. 7 is a flow diagram of logic implemented in the State Machine Module in learning phase; and,
[0051] FIG. 8 is a flow diagram of logic implemented in the State Machine Module in the protection phase.
DETAILED DESCRIPTION OF THE INVENTION
[0052] Before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not necessarily limited in its application to the details of construction and the arrangement of the components and/or methods set forth in the following description and/or illustrated in the drawings. The invention is capable of other embodiments or of being practiced or carried out in various ways.
[0053] The present invention may be embodied in a system, method or computer program product. Accordingly, aspects of the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, micro-code) or an embodiment combining software and hardware aspects that may all generally be referred to herein as a “circuit,” “module” or “system.” Furthermore, aspects of the present invention may take the form of a computer program product embodied in one or more non-transitory computer readable (storage) medium(s) having computer readable program code embodied thereon.
[0054] The invention provides, in various embodiments, methods and systems for mitigation of cyber attacks on, for example, industrial control systems and constituent devices, networks, and infrastructure. The invention is described in detail and exemplarily for an appliance protecting an electrical power infrastructure which utilizes the Modbus control protocol. The invention may also protect, for example, industrial facilities including but not limited to chemical plants, electrical power generation, transmission and distribution systems, water distribution networks, and wastewater treatment facilities, and using, for example, other protocols for industrial networks such as Distributed Network Protocol (DNP3), Object Linking and Embedding for Process Control (OPC), and the like.
[0055] Sonic embodiments of the present invention are directed to an Industrial Protection Technology Server which receives, for example, a copy of each packet that enters or traverses the industrial network.
[0056] The invention may also be embodied, for example, in a number of physical or virtualized servers which may be collocated or may be dispersed through the industrial infrastructure. The invention may also be embodied, for example, in hardware or software modules that are collocated within packet forwarding devices or packet forwarding servers/gateways, so that the invention receives each packet as it traverses the forwarding device (rather than receiving a copy of the packet).
[0057] The industrial Protection Technology Server operates in, for example, two phases: a learning phase, and a protection phase. During the learning phase, the Industrial Protection Technology Server receives real time or replayed packets which are known to represent normal operation of the ICS network, The Industrial Protection Technology Server extracts data from these packets using Deep Packet inspection (DPI), and may also, for example, collect packet metadata such as, for example, arrival time The Industrial Protection Technology Server analyzes this data to construct a “state machine” that captures the periodic properties of the communication on the ICS network. An example of ICS network communication periodic properties can be seen in the ease of a human-machine interface (HMI) device which repeatedly polls every programmable logic controller (PLC) at a fixed frequency, so that a certain pattern in the traffic is generated. An algorithm in the Industrial Protection Technology Server calculates the states of the PLCs from observing the packets captured in the communication between the PLC slave and its master.
[0058] The Industrial Protection Technology Server transitions between learning phase and protection phase according to, for example, a command invoked by a human administrator on a console of the Industrial Protection Technology Server. Alternatively, the transition may be triggered automatically by, for example, a timer, an event, or the like.
[0059] During the protection phase, the Industrial Protection Technology Server receives, for example, real time or replayed packets so that it may determine whether anomalous events are taking place on the ICS network. The Industrial Protection Technology Server extracts data from these packet's using Deep Packet Inspection (DPI), and also, for example, collects packet metadata such as, for example, arrival time. The ICS uses, for example, this data in conjunction with the state machine constructed during the learning phase to determine whether particular packets are normal or anomalous.
[0060] When an anomalous packet is detected, the industrial Protection Technology Server takes protective action such as, for example, alerting a site's security officer via a message to a console or the like. Alternatively, the Industrial Protection Technology Server may, for example, take action to block the packets that are part of the suspected attack, or take action to automatically shut down a network-attached device that appears to have been compromised.
[0061] Reference is now made to FIG. 1 , which shows an exemplary system environment (based on topologies described in National Institute of Standards and Technology (NIST) 800 - 82 ) including an Industrial Protection Technology Server embodying the invention which protects an ICS. Examples of ICS include: power generation systems; oil and gas upstream, midstream or downstream systems; and wastewater plants. The ICS comprise, for example, three sections: the field network/substation 130 , the control network 140 , and the corporate network 150 .
[0062] There may be many instances of the field network/substation 130 in a deployment. The field network/substation 130 includes, for example, equipment 137 dedicated to power generation and to voltage monitoring. This equipment 137 is linked to a network via, for example, Remote Terminal Units (RTUs) 132 , Relay Modules 134 , or Programmable Logic Controllers (PLCs) 136 supporting, for example, the Modbus protocol. These devices act, for example, as slave devices which respond to read register, write register, and other control commands from the Control Server 146 .
[0063] The RTUs 132 , PLCs 136 , and Relay Modules 134 in the field network substation 130 are, for example physically linked to a network. The, network is, for example, a serial link attaching each device to an industrial switch or multiplexer 138 which also attaches to, for example, a field network-control network communications link 160 that provides connectivity between the field network substation 130 and the control network 140 .
[0064] The field network-control network communications link 160 is, for example, a wired link such as, for example, optical Ethernet. The control protocol used to manage the RTUs 132 , Relay Modules 134 , and PLCs 136 may be tunneled over, for example, IP/Ethernet, enabling use of, for example, Modbus-over-TCP/IP.
[0065] Alternatively the field network-control network communications link 160 may be another kind of link such as, for example, General Packet Radio Service (GPRS), Category 5 twisted-pair Ethernet, and the like.
[0066] Alternatively, the control network 140 and field network 130 may, for example, be integrated in a single network entity.
[0067] The control network 140 includes the control server 146 which acts, for example, as the ICS master using, for example, the Modbus protocol to control, for example, the RTUs 132 , Relay Modules 134 , and PLCs 136 . The control server 146 is linked, for example, via Ethernet to, for example, an Ethernet switch 148 which is also linked, for example, to the field network-control network communications link 160 .
[0068] The control network also includes, for example, the industrial Protection Technology Server of the invention 142 and its associated human-machine interface (HMI) 144 , which both link, for example, to the switch 148 . The switch 148 is configured so that, for example, every packet received by the switch 148 is copied also to the Industrial Protection Technology Server 142 . This may be accomplished, tot example, using port mirroring technology such as Switch Port ANalyzer (SPAN). Alternatively, test access point (TAP) technology may be used.
[0069] Alternatively, the Industrial Protection Technology Server 142 may link, for example, directly to the industrial switch or multiplexer 138 .
[0070] The Ethernet switch 148 is also linked to for example, the control network-corporate network communications link 175 . The control network-corporate network communications link 175 is, for example, an Ethernet link and connects, for example to the corporate network switch 156 .
[0071] Alternatively the control network-corporate network communications link 175 may be another kind of link such as, for example, General Packet Radio Service (GPRS). Category 5 twisted-pair Ethernet, and the like.
[0072] Alternatively, the corporate network and control network may, for example, be integrated in a single network entity.
[0073] The corporate network 150 is linked to the control network 140 via the control network-corporate network communications link 175 . The corporate network may include, for example, personal computers (PCs) 152 , and servers 158 .
[0074] The cyber security management console 154 is the device that receives, for example, indications from the Industrial Protection Technology Server 142 when a potential cyber attack has been detected. The cyber security management console 154 also links to the corporate network switch 156 via, for example, twisted-pair copper Ethernet.
[0075] The internal architecture of the Industrial Protection Technology Server 142 is shown in FIG. 2 . The Industrial Protection Technology Server 142 includes Network Interfaces 240 , Data Collection Module 250 , Network Topology Database 255 , optional Scenario-based Alert Module 260 , optional Scenarios for Alert Database 265 , State Machine Module 270 , Network Behavior State Machine 275 , and Management Module 280 . These modules may be, for example, software modules running on a general purpose computer including a CPU, memory, and storage.
[0076] The database modules (Network Topology Database 255 , optional Scenarios for Alert Database 255 , Network Behavior State Machine 275 ) are implemented, for example, in system storage. Alternatively, some or all of the database modules may, for example, be located in remote servers or in a big data repository located in the Control Network 140 or the Corporate Network 150 .
[0077] The Network interfaces 240 are, for example, physical, virtual, or logical data links for communication with computers and devices inside or outside the facility.
[0078] The Data Collection Module 250 is, for example, a software module which, for example, reads packets from Network Interfaces 240 . The Data Collection Module 250 performs Deep Packet Inspection (DPI) on, for example, each received packet, and extracts, for example, packet data and metadata for use by the optional Scenario-based Alert Module 260 and State Machine Module 270 .
[0079] The Network Topology Database 255 maintains information about the master devices and slave devices that have been detected on the ICS. The Network Topology Database 255 is populated, for example, by the Data Collection Module 250 during the learning phase, and is utilized, for example, by the optional Scenario-based Alert Module 260 and State Machine Module 270 , during the protection phase. The process executed by the Data Collection Module 250 is shown below with reference to FIG. 3 .
[0080] The term “scenario” refers to a set of network event-matching criteria that consists of packet-matching data and/or packet metadata and/or stateful information for matching packets or a series of packets, as well as a directive regarding what to do when the scenario has been satisfied. An exemplary scenario data structure is shown in FIG. 8 .
[0081] The optional Scenario-based Alert Module 260 , when present, applies, for example, each packet received (in the protection phase of operation) to the network event detecting scenarios in the optional Scenarios for Alert Database 265 . In this manner, the optional Scenario-based Alert Module 260 detects, for example, packets which are not in compliance with the specifications of the industrial protocols, packets including known threats, operational events such as new ports or failed devices, and the like. When the Scenario-based Alert Module 260 detects such events (by matching one of the scenarios in the Scenarios for Alert Database 265 ) it, for example, raises an alert, The Scenario-based Alert Module 260 may, for example, utilize the Network Topology Database 255 in its analysis. The detailed process executed by the Scenario-based Alert Module 260 is depicted below with reference to FIG. 5 .
[0082] The optional Scenarios for Alert Database 265 includes, for example, a list of criteria describing network events. The network event scenarios are loaded into the Scenarios for Alert Database 265 by, for example, the Management Module 280 .
[0083] The State Machine Module 270 receives, for example, packet data and metadata from, for example, the Data Collection Module 250 . The State Machine Module 270 operates differently according to whether the ICS appliance is in learning phase or protection phase. In the learning phase, the State Machine Module 270 analyzes received packet data/metadata to create the Network Behavior State Machine 275 . In the protection phase, the State Machine Module 270 analyzes, for example, each received packet in conjunction with the Network Behavior State Machine 275 to identify anomalous network events and, for example, raise an alert. The process executed by the State Machine Module 270 in the learning phase is illustrated in detail below, with reference to FIG. 5 . The process executed by the State Machine Module 270 in the protection phase is illustrated in detail below, with reference to FIG. 6 .
[0084] The Management Module 280 is responsible for exchanging management requests and information with, for example, the Human Machine Interface 144 , as well as, for example, other modules within the Industrial Protection Technology Server 142 , and the Cyber Security Management Console 154 . Management functionality of the Human Machine Interface 144 may include, for example, transitioning the Industrial Protection Technology Server between learning phase and protection phase. Indications sent by the Management Module 280 to the Cyber Security Management Console 154 include, for example, alerts indicating reception of suspicious packets.
[0085] The procedure followed by the Data Collection Module 250 is illustrated as a flow diagram in FIG. 3 . With this flow diagram, as with other flow diagrams herein, the processes and/or subprocesses of the flow diagrams, are, for example, performed either automatically, manually, and combinations thereof, and in real time.
[0086] At block 305 , the system receives a packet from, for example, a Network Interface 240 . Alternatively, the Data Collection Module 250 process may also receive a packet from, for example, a packet capture that resides in a file on a hard drive.
[0087] At block 310 , the Data Collection Module 250 process performs deep packet inspection (DPI) on the packet. At block 315 , the protocol type is determined on the basis of, for example, the result of the deep packet inspection. For example, in a deployment where transport protocols are encapsulated in the Ethernet protocol (as in a ease where Modbus-over-Transport Control Protocol/Internet Protocol (TCP/IP) is utilized), the Data Collection Module 250 process may examine Ethernet fields such as the ether type or Virtual Local Area Network (VLAN) Id, together with higher layer fields such as Modbus function code and unit identifier, Payload data such as the data structures carried in a DNP3 message may also, for example, be used to determine the protocol type.
[0088] Alternatively, the system may determine the protocol type without deep packet inspection. For example, in a circumstance where the physical interface of the industrial Protection Technology Server is a Modbus controller, only Modbus may be received, In this situation, the deep packet inspection may be unnecessary and thus omitted.
[0089] The protocol type may be, for example, one of the ICS protocols used in industrial settings. These include Modbus, OPC, International Electrotechnical Commission (IEC) 61850 DNP3, and the like. The protocol type may also be, tot example, one of the ICS protocols encapsulated in a transport protocol such as TCP/IP e.g., Modbus-over-TCP/IP, DNP3-over-TCP/IP and the like. It will be understood that this method is general, and applies equally to any type of message format or protocol which appears on the network.
[0090] At block 320 , the system selects specific fields from, for example, the received packet which reveal, for example, the cyclical behavior of the industrial network. The industrial network traffic may use a protocol in which for example, a controller-type entity repeatedly sending inquiries or commands to devices, which perform an industrial process. In such an industrial network, the system may, for example, select the fields of the protocol which signify the identities of the peers and the particular commands and queries.
[0091] For example, in the specific case of a packet whose protocol type is Modbus, the 1 byte slave address may, for example, be part of such a data set that reveals the cyclical nature of the transactions on the industrial network. The Modbus function code field is another example of packet data that may be part of such a data set. Packet metadata such as arrival time and physical input port may also be part of such a data set.
[0092] At block 325 , the system updates the Network Topology Database 255 to, for example, reflect the addresses of the master and slave communicating in the current packet. The process may also, for example, eliminate inactive addresses from the Network Topology Database 255 . These updates to the Network Topology Database 255 are, for example, performed when the Industrial Protection Technology Server is in the learning phase only.
[0093] At block 330 , the system optionally stores network forensic data associated with the packet, to be used later if, for example, an alert is generated. At block 335 , the system prepares a data vector based on the selected data set. At block 340 , the system passes the data vector to, for example, the State Machine Module 250 .
[0094] FIG. 4 shows an exemplary vector created by the Data Collection Module 250 from a packet containing the Modbus protocol. The vector begins with the 8-bit Modbus Slave Address 410 , followed by the Modbus Function Code 420 . Finally there is Metadata 430 , such as input port or arrival time.
[0095] The vector illustrated in FIG. 4 serves as an example only and does not intend to specify a particular data structure or content. Deployments with other topologies or other industrial protocols may utilize different vector formats.
[0096] The procedure followed by the optional Scenario-based Alert Module 260 is illustrated as a flow diagram in FIG. 5 . Processing begins with block 505 . At block 510 the first scenario from, for example, the Scenarios for Alert Database 265 is selected.
[0097] At block 520 , the packet is applied to the packet-matching specifications in the scenario (if present). The packet matching specifications include offsets and data patterns to be evaluated in the packet. For example, a packet-matching specification may specify a particular destination IP (Internet Protocol) address known to belong to a malicious site. The result of the application of the packet to the packet-matching specifications in the scenario will be, for example, either a “match” or a “non-match”.
[0098] At block 530 , the packet is applied to the metadata-matching specifications of the scenario (if present). For example, a metadata-matching specification may specify a particular input port that requires special supervision. Alternatively, a metadata-matching specification may, for example, specify a particular interpacket arrival time value or range. The result of the application of the packet to the metadata-matching specifications in the scenario will be, for example, either a “match” or a “non-match”.
[0099] At block 540 , the packet is applied to the stateful characteristics specifications of the scenario (if present). For example, if the scenario is specified to match upon detecting the disappearance of a device, then a packet that constitutes an unanswered request (after a certain threshold of unanswered requests) will constitute a match. The application of the packet to the stateful characteristics specifications of the scenario may also, for example, change stateful contents of the specification (e.g., counters and timers).
[0100] At block 550 the system determines whether the application of the packet to the scenario structure resulted in a match for each of the 3 specifications in the scenario (i.e., packet matching, metadata-matching, stateful characteristics matching). If so then at block 530 the system examines the Directive 699 associated with the matched scenario. If the directive is to alert, then at block 560 the Scenario-based Alert Module 260 process, raises an alert by, for example, displaying a message on an administrator's console. Alternatively, the system may, for example, send a signal to the Management Module 280 that a particular event has been detected.
[0101] The process then returns to block 510 , and the next scenario is selected. If the list of scenarios is exhausted, then at block 570 Scenario-based Alert processing is completed until a new packet is received.
[0102] FIG. 6 illustrates an exemplary scenario data structure, The exemplary packet-based scenario data structure begins with an optional Packet-matching Specification 610 . The Packet-matching Specification 610 comprises, for example, one or more packet pattern matching tuples, where each packet matching tuple comprises, for example, an Offset value indicating where in the packet the pattern should be matched, a data-matching pattern and a value indicating the length of the pattern to be matched.
[0103] The optional Metadata-matching Specification 620 comprises, for example, a series of metadata-identifier and metadata-value pairs, where each pair identifies a type of metadata and a value to be matched. For example the metadata-identifier and metadata value pair may specify that if the packet input port is port 0 then a match occurs. Alternatively, for example, the metadata-identifier and metadata value pair may specify that if the packet interarrival time is below a certain value, then a match occurs.
[0104] The optional Stateful Characteristics Specification 630 comprises, for example, a series of stateful characteristic identifier, stateful characteristic value, and persistent state tuples, where each tuple identifies a type of stateful characteristic and a value to be matched, and includes persistent state information so that checks can be made across packets. For example, the stateful characteristic identifier and stateful characteristic identifier pair may specify that if 1000 instances of a particular packet are received in a 1 second interval, then a match occurs.
[0105] The directive 699 specifies how the packet should be handled if the packet data, metadata, and stateful characteristics specifications result in a match with a packet. The directive 699 may have, for example, two values: one value to signify that the packet trigger an alert, and as second value to indicate that the packet should not trigger an alert.
[0106] The exemplary procedure followed by the State Machine Module 270 while in learning phase is shown in as a flow diagram in FIG. 7 . At block 705 , the process begins. At block 710 , the system receives an input vector from, for example, the Data Collection Module 250 . The vector represents data fields and metadata from a packet in a normal sequence of packets. At block 715 , the system applies the clustering algorithm to the received vector resulting in a numerical value that is termed the “initial state” and is also the “current state”. At block 720 , the system selects the entry in the Network Behavior State Machine 275 table that corresponds to the initial state. At block 725 , the system receives either another vector, and an instruction to transition to the protection phase. If another vector was received, then at block 730 the clustering function is applied to the vector, resulting in a numerical value that is termed the “new state”. At block 735 , the system increments the transition counter in the Network Behavior State Machine 275 table entry that counts transitions between the current state and the new state. At block 740 , the value of the “current state” is set to the value of the “new state”. Control then returns to block 720 , to select the state control data for the new current state. When an instruction to transition to protection phase is received, then at block 745 the learning phase ends.
[0107] This description of the Machine Learning Engine 270 procedure during the learning phase determines a “state” upon the receipt of a new input vector from a received packet. Other embodiments may behave differently. For example, the procedure in a particular embodiment may accumulate a fixed number of packets before applying the clustering function to determine a new state, Alternatively the procedure may, for example, receive a stream of packets until a particular event and then apply the clustering function to the accumulated packets to determine a new state.
[0108] The procedure followed by the Machine Learning Engine 270 while in protection phase is shown in FIG. 8 .
[0109] At block 805 , the system receives a vector. At block 810 , the system applies the clustering algorithm to derive the “new state” from the received vector. At block 815 , the system uses the transition count information in the Network Behavior State Machine 275 to compute the probability that the new state follows the current state. At block 820 , the system uses the result of the computation of block 815 , in conjunction with the results of the computations of block 815 on previous vectors, to compute the probability of the sequential occurrence of the last “k” states (where “k” is a constant that is specific to the embodiment and is greater than 2). At block 825 , the system compares this probability to an alert threshold. If the probability is below the alert threshold, then an anomaly has occurred and at block 830 , the system takes protective action such as, for example, raising an alert. Control then returns to block 805 for receipt of the next vector.
[0110] In its processing, the Machine Learning Engine 270 may also for example, perform “cross-correlation” with other instances of the Industrial Protection Technology Server. In “cross-correlation”, the Machine Learning Engine 270 , for example, enquires over the network of other Industrial Protection Technology Server instances to determine the state of the monitored parameters of those instances. The Machine Learning Engine 270 may then, for example, use this state information in its evaluation of whether the currently processed packet is anomalous or non-anomalous.
[0111] The invention has been described in detail for an embodiment wherein a copy of each packet is sent to the ICS appliance. Alternatively, an embodiment may, for example, examine each packet as it passes through a forwarding device or gateway. In such an embodiment, the determination to take protective action may, for example, be accompanied by dropping the packet rather than forwarding it.
[0112] The invention has been described in detail for an embodiment wherein the protective action taken by the ICS appliance is sending an alert to the Cyber Security Management Console 154 . Alternatively, an embodiment may, for example, take action to disable a node that is generating or forwarding anomalous traffic. In such an embodiment, the ICS appliance may, for example, use a management protocol such as SNMP to manage the particular node and disable it.
[0113] Alternatively, an embodiment may, for example, take protective action to disable node that is generating or forwarding anomalous traffic. In such an embodiment, the ICS appliance may, for example, use a management protocol such as SNMP to manage the particular node and disable it.
[0114] Alternatively, an embodiment may, for example, take protective action to program nodes in the network so that they will drop traffic that matches a particular pattern. In such an embodiment, the ICS appliance may, for example, use a management protocol such as SNMP to manage the particular node.
[0115] The flowchart and block diagrams in the Figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods and computer program products according to various embodiments of the present invention. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems that perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.
[0116] It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination or as suitable in any other described embodiment of the invention. Certain features described in the context of various embodiments are not to be considered essential features of those embodiments, unless the embodiment is inoperative without those elements.
[0117] The above-described processes including portions thereof can be performed by software, hardware and combinations thereof These processes and portions thereof can be performed by computers, computer-type devices, workstations, processors, micro-processors, other electronic searching tools and memory and other non-transitory storage-type devices associated therewith. The processes and portions thereof can also be embodied in programmable non-transitory storage media, for example, compact discs (CDs) or other discs including magnetic, optical, etc., readable by a machine or the like, or other computer usable storage media, including magnetic, optical, or semiconductor storage, or other source of electronic signals.
[0118] The processes (methods) and systems, including components thereof, herein have been described with exemplary reference to specific hardware and software. The processes (methods) have been described as exemplary, whereby specific steps and their order can be omitted and/or changed by persons of ordinary skill in the art to reduce these embodiments to practice without undue experimentation. The processes (methods) and systems have been described in a manner sufficient to enable persons of ordinary skill in the art to readily adapt other hardware and software as may be needed to reduce any of the embodiments to practice without undue experimentation and using conventional techniques.
[0119] Although the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art, Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims.
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Methods and systems for detecting a potential compromise of cyber security in an industrial network are disclosed. These methods and systems comprise elements of hardware and software for establishing a baseline of site-acceptable network behavior comprising a list of network states and transition probabilities, wherein a transition probability denotes an estimated probability of a first network state being followed temporally by a second network state during normal network operation; establishing a threshold representing tile probability below which a sequence of network states is anomalous; determining a probability for the occurrence of a sequence of network states as obtained from a particular stream of packets, according to the baseline of site-acceptable network behavior; and, taking protective action according to whether the determined probability is below the established threshold.
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RELATED APPLICATIONS
This application claims the benefit of U.S. Provisional Application No. 62/172,319, filed Jun. 8, 2015, and which is incorporated herein by reference.
FIELD OF THE INVENTION
The present invention relates to non-volatile memory cells, and more particularly to a method of forming such cells on the same wafer as logic devices.
BACKGROUND OF THE INVENTION
Split-gate type memory cell arrays are known. For example, U.S. Pat. No. 5,029,130, which is incorporated herein by reference for all purposes, discloses a split gate memory cell and its formation, which includes forming source and drain regions in the substrate with a channel region there between. A floating gate is disposed over and controls the conductivity of one portion of the channel region, and the control gate is disposed over and controls the conductivity of the other portion of the channel region. The control gate extends up and over the floating gate.
It is also known to form high voltage logic devices on the same wafer (substrate) as the split-gate memory cell array. FIGS. 1A-10A, 1B-10B and 1C-10C show the steps in forming high voltage logic devices (e.g. 12 volt logic devices) on the same wafer as the split gate memory cells. A semiconductor substrate 10 is masked (i.e. photo resist is deposited, selectively exposed using a mask, and selectively removed, using a photolithographic process, leaving portions of the underlying material covered by remaining photo resist while leaving other portions of the underlying material (here the substrate) exposed). The exposed substrate portions are etched away leaving trenches that are then filled with dielectric material 12 (e.g. oxide) to form isolation regions in the memory cell region 14 of the wafer (see FIG. 1A ), in the NMOS logic region 16 of the wafer (see FIG. 1B ) and in the PMOS logic region 18 of the wafer (see FIG. 1C ), all shown after the photo resist is removed. The wafer is then masked again, but this time to cover the NMOS logic and memory cell regions 16 and 14 with photo resist 20 , while leaving the PMOS logic region 18 exposed. A high voltage NWEL implant is then performed on the exposed PMOS logic region 18 , as shown in FIGS. 2A, 2B and 2C . The photo resist 20 blocks the implantation from the memory cell and NMOS logic regions 14 and 16 of the wafer. The photo resist 20 is removed. The wafer is then masked to cover the PMOS logic region 18 with photo resist 22 , but leaving the NMOS logic and memory cell regions 16 and 14 exposed. A high voltage PWEL implant is performed on the exposed NMOS logic and memory cell regions 16 and 14 as shown in FIGS. 3A, 3B and 3C .
After the photo resist 22 is removed, a layer of oxide 24 (FG oxide) is formed on the substrate 10 , a layer of polysilicon 26 (FG poly) is formed on oxide 24 , and a layer of nitride 28 (FG nitride) is formed on poly layer 24 , as shown in FIGS. 4A, 4B and 4C . The wafer is masked, leaving photo resist 30 on the wafer except on selected locations of the nitride 28 which are left exposed in the memory cell region 14 . The exposed nitride 28 is etched using an appropriate nitride etch to expose portions of poly layer 26 , as shown in FIGS. 5A, 5B and 5C . The exposed portions of the FG poly layer 26 are oxidized using an oxidation process, forming oxide areas 32 on the FG poly 26 . FIGS. 6A, 6B and 6C show the resulting structure after the photo resist 30 is removed. A nitride etch is used to remove the remaining nitride layer 28 . An anisotropic poly etch is used to remove exposed portions of the poly layer 26 , leaving blocks of polysilicon 26 underneath the oxide areas 32 in the memory cell region 14 (which will constitute the floating gates of the memory cells), as shown in FIGS. 7A, 7B and 7C .
An oxide layer 34 is formed over the structure. After additional masking and implant steps (logic NWEL, IO NWEL, logic PWEL, IO PWEL, LLVOX and LVOX), a layer of polysilicon is deposited over the wafer. The structure is masked leaving portions of the poly layer exposed, which are then removed by a poly etch. The remaining portions of the poly layer constitute the control gates 36 a in the memory cell region 14 , logic gate 36 b in the NMOS logic region 16 , and logic gate 36 c in the PMOS logic region 18 . The resulting structure is shown in FIGS. 8A, 8B and 8C (after the photo resist has been removed). The structure is masked again leaving only portions of the memory cell region between pairs of adjacent floating gate poly blocks 26 exposed by photo resist 38 . An implantation is performed to form source regions 40 in the portions of the substrate between the floating gate poly blocks 36 a , as shown in FIGS. 9A, 9B and 9C .
After the photo resist 38 is removed and after additional masking and implant steps (logic NLDD, IO NLDD, logic PLDD and IO PLDD), the wafer is masked again, leaving the PMOS logic and memory cell regions 18 and 14 covered by photo resist, but leaving the NMOS logic area 16 exposed. An LDD implantation is then performed on the NMOS logic region 16 . The photo resist is removed. The wafer is masked again, leaving the NMOS logic and memory cell regions 16 and 14 covered by photo resist, but leaving the PMOS logic region 18 exposed. An LDD implantation is then performed on the PMOS logic region 18 . After photo resist removal, the wafer is masked covering portions of the structure with photo resist but leaving the NMOS logic region 16 exposed and those portions of the memory cell region 16 adjacent the control gate poly blocks 36 a exposed. An N+ implantation is used to form the source/drain regions 44 and 45 in the NMOS logic region 16 and drain regions 46 in the memory cell region 14 . The photo resist is removed. The wafer is masked leaving just the PMOS logic region 18 exposed by photo resist, and a P+ implantation is used to form the source/drain regions 48 and 49 in the PMOS logic region 18 .
The photo resist is removed. The process continues by forming insulation spacers 50 , silicide layers 52 on the poly blocks 36 a , 36 b and 36 c and on all the source/drain regions, and insulation layers 54 - 57 , as shown FIGS. 10A, 10B and 10C . This back end processing includes at least two more masking steps (silicide blocking to limit silicide formation, and back end processing to create the contacts 58 through the insulation over the drain regions in the memory cell region and over the source/drain regions in the logic device regions).
The above technique produces non-volatile memory cells (each with a source 40 , drain 46 , floating gate 26 , control gate 36 a ) on the same substrate as high voltage NMOS logic devices (each with a logic gate 36 b , source 44 and drain 45 ) and high voltage PMOS logic devices (each with a logic gate 36 c , source 48 and drain 49 ). It would be desirable to reduce the complexity and cost of manufacturing the memory cells and logic devices, including the number of masking steps used.
BRIEF SUMMARY OF THE INVENTION
The aforementioned problems and needs are addressed by a method of forming a memory device that includes:
providing a semiconductor substrate having a memory region, a first logic region and a second logic region;
forming a pair of spaced apart floating gates in the memory region;
forming a pair of control gates in the memory region, wherein each control gate has a first portion adjacent to one of the floating gates and a second portion that extends up and over one of the floating gates;
forming a first logic gate in the first logic region;
forming a second logic gate in the second logic region;
forming a first photo resist that covers the second logic region and portions of the substrate adjacent to the control gates in the memory region, but not the first logic region and not a portion of the substrate between the pair of floating gates;
performing a first implantation that forms a source region in the substrate between the pair of floating gates, a source region in the substrate adjacent a first side of the first logic gate, and a drain region in the substrate adjacent a second side of the first logic gate opposite the first side of the first logic gate;
removing the first photo resist;
forming a second photo resist that covers the first logic region and the memory region, but not the second logic region;
performing a second implantation that forms a source region in the substrate adjacent a first side of the second logic gate and a drain region in the substrate adjacent a second side of the second logic gate opposite the first side of the second logic gate;
removing the second photo resist;
forming a third photo resist that covers the second logic region, but not the memory region and not the first logic region;
performing a third implantation that forms drain regions in the substrate adjacent the control gates;
removing the third photo resist.
Other objects and features of the present invention will become apparent by a review of the specification, claims and appended figures.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1A-10A are side cross sectional views illustrating conventional steps for forming memory cells in a memory cell region of the wafer.
FIGS. 1B-10B are side cross sectional views illustrating conventional steps for forming a logic device in an NMOS logic region of the wafer.
FIGS. 1C-10C are side cross sectional views illustrating conventional steps for forming a logic device in a PMOS logic region of the wafer.
FIGS. 11A-23A are side cross sectional views illustrating steps for forming memory cells in a memory cell region of the wafer.
FIGS. 11B-23B are side cross sectional views illustrating steps for forming a logic device in an NMOS logic region of the wafer.
FIGS. 11C-23C are side cross sectional views illustrating steps for forming a logic device in a PMOS logic region of the wafer.
DETAILED DESCRIPTION OF THE INVENTION
It has been discovered that by reducing the operating voltages on the logic devices (i.e. from 12 volts to 5 volts), significant reduction on the complexity and cost of manufacturing the memory cells and logic devices can be achieved. In fact, the number of masking steps can be reduced significantly.
FIGS. 11A-23A, 11B-23B and 11C-23C show the steps in forming high voltage logic devices (e.g. 5 volt logic devices) on the same wafer (substrate) as the split gate memory cells according to the present invention. A semiconductor substrate 60 is masked (i.e. photo resist is deposited, selectively exposed using a mask, and selectively removed, using a photolithographic process, leaving portions of the underlying material covered by remaining photo resist while leaving other portions of the underlying material (here the substrate) exposed). The exposed substrate portions are etched away leaving tranches that are then filled with dielectric material 62 (e.g. oxide) to form isolation regions in the memory cell region 64 of the wafer (see FIG. 11A ), in the NMOS logic region 66 of the wafer (see FIG. 11B ) and in the PMOS logic region 68 of the wafer (see FIG. 11C ). After the photo resist is removed, the wafer is then masked again, but this time to cover the PMOS logic region 68 with photo resist 70 , but leaving the memory cell and NMOS logic regions 64 and 66 exposed. A 5V PWEL implant is then performed on the exposed memory cell and NMOS logic regions 64 and 66 (e.g., to form P-wells in the N type substrate in the memory cell region 64 and NMOS logic region 66 ), as shown in FIGS. 12A, 12B and 12C . The photo resist blocks the implantation from the PMOS logic region 68 of the wafer.
After the photo resist 70 is removed, a layer of oxide 72 (FG oxide) is formed on the wafer, a layer of polysilicon 74 (FG poly) is formed on oxide 72 , and a layer of nitride 76 (FG nitride) is formed on poly layer 74 , as shown in FIGS. 13A, 13B and 13C . The wafer is masked, leaving photo resist 78 on the wafer except on selected portions of the nitride 76 which are left exposed in the memory cell region 64 . The exposed nitride 76 is etched using an appropriate nitride etch to expose portions of poly layer 74 , as shown in FIGS. 14A, 14B and 14C . The exposed portions of poly layer 74 are oxidized using an oxidation process, forming oxide areas 80 on the FG poly. FIGS. 15A, 15B and 15C show the resulting structure after the photo resist 78 is removed. A nitride etch is used to remove the remaining nitride layer 76 . An anisotropic poly etch is used to remove the poly layer 74 except those portions underneath the oxide areas 80 in the memory cell region 74 , leaving blocks of polysilicon 74 that will constitute the floating gates of the memory cells, as shown in FIGS. 16A, 16B and 16C .
The wafer is then masked to cover the NMOS logic region 66 , and the memory cell region (except for those areas between adjacent FG poly blocks), with photo resist 82 . An implant (5V PMOS/PH) is performed on those areas left exposed by the photo resist 82 , as shown in FIGS. 17A, 17B and 17C . After the photo resist 82 is removed, an oxide layer 84 is formed on the structure and the wafer. After additional masking and implant steps (Core PWEL for logic NMOS and LVOX for open core oxide region), a layer of polysilicon is deposited over the wafer. The structure is masked leaving portions of the poly layer exposed, which are then removed by a poly etch. The remaining portions of the poly layer constitute the control gates 86 a in the memory cell region 64 , and the logic gates 86 b and 86 c in the NMOS and PMOS logic regions 66 and 68 respectively. The resulting structure is shown in FIGS. 18A, 18B and 18C (after the photo resist has been removed).
After an additional masking and implant step (Core NLDD for logic NMOS and LDD), the structure is masked again leaving only the NMOS region 66 and those areas between adjacent floating gate poly blocks 74 in the memory cell region 64 exposed by photo resist 87 , followed by a 5V NLDD implantation to form the source regions 88 in the portions of the substrate between the floating gate poly blocks 74 in the memory cell region 64 and to form the source and drain regions 90 and 91 in the NMOS logic region 66 , as shown in FIGS. 19A, 19B and 19C . After the photo resist 87 is removed, and after an additional masking and implant step (Core PLDD), the structure is masked to leave only the PMOS logic region 68 exposed from photo resist 92 . This is followed by a 5V PLLD PH implantation to form source and drain regions 94 and 95 in the PMOS logic region 68 , as shown in FIGS. 20A, 20B and 20C . The purpose of the NLDD and PLLD implants is to mitigate the effect of hot carrier injection (HCl) damage and make the effective channel length shorter.
After photo resist 92 is removed, the structure is masked to cover PMOS logic region 66 with photo resist 96 , which is followed by an implantation (NNII-N+) to enhance the source region 88 and form drain regions 101 in the memory cell region 64 , and enhance the source and drain regions 90 and 91 in the NMOS logic region 66 , as shown in FIGS. 21A, 21B and 21C . After the photo resist 96 is removed, the wafer is masked with photo resist 98 except for the PMOS logic region 68 , and a P+ implantation is used to enhance the source/drain regions 94 / 95 in the PMOS logic region 68 , as illustrated in FIGS. 22A, 22B and 22C .
The process continues by forming insulation spacers 100 (e.g. by oxide deposition and etch), silicide layers 102 on the poly blocks 86 a , 86 b and 86 c and on all source/drain regions, and insulation layers 104 - 107 , as shown in FIGS. 23A, 23B and 23C . This back end processing includes at least two more masking steps (silicide blocking to limit silicide formation, and back end processing for etching through insulation layers 104 - 107 to create contact holes 108 through the insulation over the drain regions in the memory cell region and over the source/drain regions in the logic device regions).
By forming high voltage logic devices that operate at a lower voltage (e.g. 5 volts) than done in the prior art (e.g. 12 volts), it allows for certain logic region implantations to be shared with the memory cell region that could not be shared before. These different sharing arrangements allow for a reduction of masking steps from 22 down to 15 in forming the memory cells and logic devices on the same wafer.
It is to be understood that the present invention is not limited to the embodiment(s) described above and illustrated herein, but encompasses any and all variations falling within the scope of the appended claims. For example, references to the present invention herein are not intended to limit the scope of any claim or claim term, but instead merely make reference to one or more features that may be covered by one or more of the claims. Materials, processes and numerical examples described above are exemplary only, and should not be deemed to limit the claims. Further, as is apparent from the claims and specification, not all method steps need be performed in the exact order illustrated or claimed. Additionally, the above method is illustrated with an N type substrate and P wells formed in the memory cell region and the NMOS logic region. However, a P type substrate can be used, in which case an N well can be formed in the PMOS logic region. Lastly, single layers of material could be formed as multiple layers of such or similar materials, and vice versa.
It should be noted that, as used herein, the terms “over” and “on” both inclusively include “directly on” (no intermediate materials, elements or space disposed there between) and “indirectly on” (intermediate materials, elements or space disposed there between). Likewise, the term “adjacent” includes “directly adjacent” (no intermediate materials, elements or space disposed there between) and “indirectly adjacent” (intermediate materials, elements or space disposed there between), “mounted to” includes “directly mounted to” (no intermediate materials, elements or space disposed there between) and “indirectly mounted to” (intermediate materials, elements or spaced disposed there between), and “electrically coupled” includes “directly electrically coupled to” (no intermediate materials or elements there between that electrically connect the elements together) and “indirectly electrically coupled to” (intermediate materials or elements there between that electrically connect the elements together). For example, forming an element “over a substrate” can include forming the element directly on the substrate with no intermediate materials/elements there between, as well as forming the element indirectly on the substrate with one or more intermediate materials/elements there between.
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A method of forming a memory device on a semiconductor substrate having a memory region (with floating and control gates), a first logic region (with first logic gates) and a second logic region (with second logic gates). A first implantation forms the source regions adjacent the floating gates in the memory region, and the source and drain regions adjacent the first logic gates in the first logic region. A second implantation forms the source and drain regions adjacent the second logic gates in the second logic region. A third implantation forms the drain regions adjacent the control gates in the memory region, and enhances the source region in the memory region and the source/drain regions in the first logic region. A fourth implantation enhances the source/drain regions in the second logic region.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a phased-array semiconductor laser and more particularly to an output structure for the laser.
2. Description of the Relevant Art
Phased-array lasers include a set of directly coupled waveguide amplifiers which generate in-phase light waves. Each waveguide has a terminal aperture at a laser facet that radiates the light waves generated in the waveguide amplifier. Typically, a radiated output beam from the phased-array laser includes a high-intensity central lobe and several low intensity sidelobes. These sidelobes increase the width of the beam and divert energy from the central beam.
Many laser applications require a highly resolved output beam. Accordingly, much effort has been expended to develop a phased-array laser that produces an output beam having only a single lobe. It is well-known that for an array of radiators having aperture size S and spacing distance D the ratio of S to D must be greater than 75% to obtain a single-lobed output beam.
In existing systems, the output waveguides are forward biased to amplify the light waves propagating therethrough. Thus, if the distance, D, between waveguides is reduced to obtain a single-lobed output beam then evanescent coupling between the output waveguides will occur. Conversely, if the output waveguides are flared to increase the size of the output apertures then higher order transverse modes may be supported. Either evanescent coupling or higher order modes may destabilize the laser output beam.
In U.S. Pat. No. 4,718,069 Streifer et al. teach variable spacing of the output waveguides to achieve a single-lobed output beam. Y-shaped couplers are used to assure coupling between widely spaced output waveguides and the output waveguides are forward-biased to achieve light amplification.
Additionally, many systems, such as a facet scanning system or optical fiber array input scanning, require an output beam which may be scanned in a controllable manner. Typically, an output structure utilizing scanning electrodes is used to vary the index of refraction according to some function across the array. Generally, the bias induced by the scanning electrode is impressed on an amplifying portion of the laser and interferes with the bias applied to cause amplification. Such interference can affect the stability of the laser output beam.
SUMMARY OF THE INVENTION
According to one aspect of the present invention, an output structure includes a set of output waveguides which are transparent to the light generated by the laser. The output structure does not amplify the light waves generated in the laser and thus does not affect the output stability of the laser.
According to a further aspect of the invention, the width of the output waveguides is less than the critical width required to completely confine the guided light waves within the waveguide so that the spot size of light radiated from the output waveguides is increased to greater than about 75% of the spacing between the waveguides to produce a single-lobed output beam.
The problems of evanescent coupling and support of extra modes are obviated because there is no gain in the transparent output waveguides which support only one mode.
According to another aspect of the invention, a scanning contact electrode pair is used to bias an array of transparent output waveguides to scan a laser output beam. The output stability of the laser is not adversely affected because the scanning bias is not applied to gain regions of the laser.
Additional advantages and features of the invention will be apparent in view of the appended drawings and following detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross-sectional view of a typical layer structure in a semiconductor laser;
FIG. 2A is a top view of a semiconductor laser array incorporating a preferred embodiment of the output structure of the present invention;
FIG. 2B is a perspective view of a hybrid structure including a separate laser and coupler;
FIG. 2C is top view of a laser array having two output structures;
FIG. 2D is a top view of a laser array having a y-coupled passive output structure;
FIG. 3 is a graph of the light wave intensity for an index-guided waveguide;
FIGS. 4A-4E are graphs depicting output beam intensities; and
FIG. 5 is a top view of a semiconductor laser array incorporating a preferred embodiment of the scanning system of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The primary focus of the invention is the provision of an improved output structure for forming a single-lobed output beam that avoids the problems of the prior art.
Referring now to FIGS. 1 and 2A, there is illustrated an enlarged view of a semiconductor structure 10 comprising a plurality of epitaxially deposited layers 22-28 on substrate 20. As an example of a semiconductor structure 10 is a semiconductor heterostructure comprising a central section 11, which may be an active medium, and a passive waveguide section 13 separated by a boundary 15. Structure 10 may include a substrate 20, which may be comprised of n-GaAs, on which are consecutively deposited in an MO-CVD reactor epitaxial layers 22-28, as is known in the art. These epitaxially deposited layers may be, for example, as follows: Cladding layer 22 of n-Ga 1-y Al y As wherein, for example, y=0.40; active region 24 comprising a layer of GaAs or Ga 1-x Al x As where y>x, or a single quantum well layer of GaAs or a multiple quantum well of alternating layers of GaAs and Ga 1-x Al x As or alternating layers of Ga 1-x Al x As and Ga 1-z Al z As where y>z>x; cladding layer 26 of p-Ga 1-y Al x As and a cap layer 28 of p+GaAs. In the particular example here, active region 24 comprises multiple quantum wells. This multiple well structure is comprised of four 12 nm quantum wells of Ga 1-x Al x As, wherein x=0.05, separated by three 6 nm barriers of Ga 1-z Al z As, wherein z=0.20. Therefore, the layer structure has a width, L z , of approximately 66 nm.
In FIG. 2A, a set of index-guided stripes 30, disposed in the active layer 24 of the central section 11, are joined in a Y-coupled configuration. The central section is forward-biased so that light of a given wavelength is generated and amplified under lasing conditions. The Y-couplers cause excited out-of-phase modes to radiate from the straight sections and cause the light waves generated in the stripes 30 to be phase locked. Y-guides are used as an example of any configuration that leads to phase locked operation in the fundamental mode.
A set of index-guided output waveguides 32, disposed in the active layer 24 of the output section 13, are oriented co-axially to the stripes 30 and joined thereto at the boundary 15. These output waveguides 32 are narrower than the stripes 30 and are transparent to the light waves generated in the stripes 30. This set of waveguides serves as an output coupler for the phase-locked array.
A method for forming the index-guided stripes 30 and transparent index-guided waveguides 32 is fully disclosed in U.S. Pat. No. 4,802,182 to Thornton et al. and is hereby incorporated by reference. Alternatively, laser patterned desorption (LPD) waveguides may be utilized. This process is disclosed in U.S. Pat. No. (corresponding to Ser. No. 07/328,988 and Ser. No. 07/257,498) which are thereby incorporated by reference.
The active layer 24 in index-guided stripes and waveguides 30 and 32 has a greater index of refraction than the neighboring areas of active layer 24 and of cladding layers 22 and 26. Thus, the light generated in the stripes and waveguides 30 and 32 is confined by the well-known phenomena of total internal reflection.
FIGS. 2C and 2D depict alternative embodiments. In FIG. 2C output couplers 13a and b are attached to each end of the amplification part 11 of the array. In FIG. 2D the output coupler 13 is a passive y-coupled array that phase-locks the light generated in the amplification section 11.
FIG. 3 is a planar top view schematically depicting the amplitude of the light waves in an index-guided stripe or waveguide 30 or 32 formed in the active region 24. As stated above, the index of refraction of the stripe or waveguide 30 or 32 is greater than the index for the exterior part 24e of the active region 24. The line 39 indicates the strength of the light wave field. In the exterior region 24e the strength of the field decays proportionally to exp[-S/2(abs(x))] so that the spreading of the light becomes greater when the width of the waveguide becomes smaller.
The characteristics of the output beam emitted from the output waveguides 32 will now be described with reference to FIGS. 4A-4E. The near-field emission pattern is depicted in FIG. 4A where W is the spot width of the light radiated by each output waveguide 32 and D is the spacing between the centers of the output waveguides 32. The far-field single waveguide emission pattern 40 of each waveguide is depicted in FIG. 4A and the point array pattern 2 of an array of point emitters separated by D is depicted in FIG. 4C. The single waveguide pattern 40 has a very small magnitude for values of theta greater than a cut-off point equal to about λ/W. The actual array pattern for the array depicted in FIG. 4A is the product of the emission patterns of FIGS. 4B and 4C and is depicted in FIG. 4D.
Note that in FIG. 4D the constant heights of the peaks of the point array pattern 42 are modulated by the single waveguide pattern 40. As depicted in FIG. 4D, for a spot width greater than W s only the first peak will be located before the cut-off point of the single waveguide pattern 40 so that the array pattern 44 will be single-lobed as depicted in FIG. 4E.
As is well-known in the art, a single lobed output beam is obtained when W is equal to about 0.75 D. Typically, waveguides have been designed to obtain nearly complete confinement of the guided light waves so the W, the spot width, is equal to S, the width of the waveguide. Attempts to increase S lead to the problems of extra modes and evanescent coupling described above.
In the present system, the width of the waveguides is decreased below a critical width necessary to obtain complete confinement so that the optical field begins to spread as described above with reference to FIG. 3. Typically, for GaAs lasers this critical width is about 1 micron. Since the output waveguides 32 are narrowed they do not physically interfere as in prior art structures.
Additionally, the output waveguides are transparent so that no biasing is required to reduce absorption. Accordingly, the output structure is not affected by changes in bias voltages or current densities in the active medium 24.
FIG. 5 depicts a system for scanning the farfield angle of the output beam of the laser array. In FIG. 5 a pair of triangular shaped scanning contact pairs 50 and 52 are disposed on the top surface of the second part 13 of the substrate 10. Each contact pair 50 or 52 has a first edge oriented parallel to the boundary 15 and a second edge oriented at 45° to the boundary.
A scanning voltage is applied to the scanning contacts 50 or 52 to reverse-bias the activated length of each output waveguide 30 disposed between the scanning contacts to provide a phase shift in the beam radiated from each output waveguide 30 via the electro-optic effect. The magnitude of the phase shift, P, induced in a given output waveguide 30 is proportional to the length of the output waveguide 30 which is reverse-biased and is equal to:
P=4πLn/λ
where n is the index of refraction and λl0 is the wavelength of the generated light waves.
The induced phase shift, P, can be varied by varying the magnitude of the scanning voltage applied to the scanning contacts 50 or 52. In the embodiment depicted in FIG. 5, for the triangular first contact pair 50 the magnitude of the activated length of each output waveguide 30 varies linearly across the array of output waveguides. This linear variation results in a scanning angle β defined by the relationship:
sinβ=Pλ/2πD.
Applying a scanning voltage to the first contact pair 50 increases the phase shift from the bottom to the top of the output waveguide array and therefore scans the beam in a first direction. Biasing the second contact pair 52 increases the phase shift from the top to the bottom of the array and therefore scans the beam in an opposite direction.
The scanning contact pairs 50 and 52 may be forward-biased to obtain a phase-shift due to the variation of the index of refraction caused by the free carrier effect. Further, the shape of the contacts may be changed to vary the magnitude of the activated length across the output waveguide array according to a predetermined function.
The edge of the contact 52 can have other geometric shapes. For example, if the edge were shaped as a parabola the width of the central lobe could be increased.
The bias induced by the scanning electrode pairs 50 or 52 is applied to the second part 13 of the structure where the output waveguides do not function to amplify the light waves generated in the stripes 30. Accordingly, this scanning bias does not interfere with the forward bias used to achieve amplification in the stripes 30 so that the laser output is stable. It is not required to amplify the light waves propagating in the output waveguides 32 because these waveguides 32 are transparent to the light waves generated in the stripes 30.
The invention has now been described with reference to the preferred embodiments and substitutions and modifications will now be apparent to persons of ordinary skill in the art. For example, as depicted in FIG. 2B the coupler 13 and laser 11 may be separate hybrid structures joined at boundary 15. In that case the output waveguides 16 could be formed using lithium niobate. Accordingly, the invention is not intended to be limited except as provided by the appended claims.
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A semiconductor laser array includes a set of low-loss waveguides for transmitting generated light waves to an external facet. The width of the output waveguides is less than a critical width required for complete confinement of the transmitted light so that the spot width of the light transmitted by each waveguide is increased to greater than 75% of the spacing between the output waveguides to produce a single-lobed beam. In one embodiment, scanning contacts induce a bias on a set of low-loss output waveguides to scan an output beam.
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This is a Non Provisional application filed under 35 USC 119(e) and claims priority of prior provisional, TI-18740P, Ser. No. 60/032,446 of inventor Vogley, et al., entitled Selectable Memory Modules and Method of Operation, filed Dec. 19, 1996 and TI-18740P1, Ser. No. 60/066,569, of inventor Vogley, et al, entitled Selectable Integrated Circuit Assembly and Method of Operation, filed Nov. 26, 1997.
TECHNICAL FIELD OF THE INVENTION
This invention relates in general to the field of electronic systems, to a selectable integrated circuit assembly, and more particularly to a selectable memory module and a method of operation.
BACKGROUND OF THE INVENTION
Computer systems, such as personal computers and computer workstations, typically have a number of integrated circuit assemblies as components. These integrated circuit assemblies can include, for example, a mother board. With respect to memory modules, some computer systems require memory modules, for example DRAM or synchronous DRAM modules, that operate at clock frequencies of greater than 100 MHz. Conventional memory modules can have problems with interconnect, noise and physical space that are augmented by such high operating frequencies. A bus system clocked, for example, at 100 MHz should have minimal load per driver to reduce noise and improve integrity of the signal. However, eight conventional memory modules on a single bus driver can add, for example, forty picofarads of capacitance to a base of approximately twenty picofarads.
Many computer system manufacturers contemplate having several gigabytes of main memory which may require a large number of memory modules per bus. This number of memory modules may produce problems with respect to the load on the bus drivers at high operating frequencies. Thus, these systems may need a type of memory module that is different from conventional single in-line memory modules (SIMM) or other conventional memory modules.
SUMMARY OF THE INVENTION
In accordance with the present invention, a selectable integrated circuit assembly, and more particularly a selectable memory module, and a method of operation are provided.
According to one aspect of the present invention, a selectable integrated circuit assembly is disclosed. The assembly includes a first plurality of terminals for communicating information to and from an integrated circuit device and a second plurality of terminals for receiving an assembly address. The assembly also includes select logic connected to receive the assembly address and operable to generate select signals based upon the assembly address. The select signals have a is selected state and a not-selected state. A plurality of switches are connected between the first plurality of terminals and the integrated circuit device. The plurality of switches are connected to receive the select signals. The switches operate, when the select signals are in the selected state, to connect the first plurality of terminals to the integrated circuit device. When the select signals are in the non-selected state, the switches operate to disconnect the first plurality of terminals from the integrated circuit device. According to one embodiment of the present invention, the assembly is a selectable memory module.
According to another aspect of the present invention, a method is provided for selecting a memory module on a memory bus. A plurality of memory modules are connected to a memory bus. Each memory module comprises a first plurality of terminals for communicating information to and from memory devices on the memory module, and a second plurality of terminals for receiving a module address. A module address of a desired memory module is communicated to the plurality of memory modules via the second plurality of terminals. Each memory module is then operable to connect the first plurality of terminals to the memory bus responsive to receiving a module address corresponding to the memory module, and to disconnect the first plurality of terminals from the memory bus responsive to receiving a module address not corresponding to the memory module.
A technical advantage of the present invention is the ability to control the electrical connection to an integrated circuit assembly such that the assembly can be isolated. While isolated, the integrated circuit assembly can, for example, be disconnected from a system bus in a computer system. One type of integrated circuit assembly to which this can be applied is a memory module that provides system memory.
A further technical advantage of the present invention is the mounting of memory devices on a modular board similar to existing SIMMs but with an input/output (I/O) circuit for interface control. The interface control handles signal integrity at the board level and isolates the memory module, when not being addressed, from the system bus. Thus, by isolating the memory module, the load on the bus is reduced thereby allowing more efficient driving of signals on the bus especially at high frequency. This advantage can apply to providing selectability for other configurations and other integrated circuit assemblies.
BRIEF DESCRIPTION OF THE DRAWINGS
A more complete understanding of the present invention may be acquired by referring to the following description taken in conjunction with the accompanying drawings, in which like reference numbers indicate like features, and wherein:
FIGS. 1A and 1B are block diagrams of one embodiment of a selectable memory module constructed according to the teachings of the present invention;
FIG. 2 is a block diagram of one embodiment of pins of a selectable memory module constructed according to the teachings of the present invention;
FIG. 3 is a block diagram of one embodiment of using module address pins to determine whether or not to select a given memory module according to the teachings of the present invention;
FIG. 4 is a block diagram of one embodiment of a selected memory module within a bus scheme according to the present invention;
FIG. 5 is a block diagram of one embodiment of a selectable memory module socket constructed according to the teachings of the present invention;
FIG. 6 is a block diagram of a selectable memory module constructed according to the teachings of the present invention;
FIG. 7 is a block diagram of another embodiment of a selectable memory module socket constructed according to the teachings of the present invention;
FIGS. 8A, 8B and 8C are diagrams of embodiments of bus termination according to the teachings of the present invention;
FIG. 9 is a circuit diagram of one embodiment of a switch for a selectable memory module according to the teachings of the present invention;
FIG. 10 is a cross section diagram of one embodiment of an integrated circuit bond pad; and
FIG. 11 is a block diagram of switches on a selectable memory module constructed according to the teachings of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
FIGS. 1A and 1B are block diagrams of one embodiment of a selectable memory module constructed according to the teachings of the present invention. As shown in FIG. 1A, a memory module 10 is connected to a bus 12 for communicating with other components of a computer system. As shown in FIG. 1B, memory module 10 includes module select logic 14 and a plurality of terminals 16. A plurality of switches 18 are connected to terminals 16 to allow disconnection of memory module 10 from and connection of memory module 10 to bus 12. It should be understood that although a memory module is shown, the selectability provided by the present invention is applicable to other integrated circuit assemblies as well. In the illustrated embodiment, terminals 16 comprise address and I/O pins of memory module 10, and switches 18 comprise T-gates that connect between pins 16 and remaining circuitry of memory module 10. T-gates 18 of FIGURE 1B allow each I/O and address pin 16 of memory module 10 to be electrically connected to or disconnected from bus 12. In this manner, memory module 10 can both be connected to and load bus 12 and be disconnected from and not load bus 12. Other types of switches could also be used in place of T-gates 18 to provide selectability via electrically controllable connections to memory module 10.
Memory module 10 adds more to the load on bus 12 (e.g., about ten picofarads) when selected than it adds to the load on bus 12 (e.g., about 0.1 picofarads) when not selected. According to the present invention, memory module 10 is selectable and can be isolated using T-gates 18. Thus, when not needed, memory module 10 is not selected and is disconnected from bus 12. This selectability helps both drive current and reduces reflections at lower power and higher speed.
In one embodiment, T-gates 18 are implemented using bipolar devices for speed, for example, gallium arsenide (GaAs) devices. An example of such an embodiment is illustrated in and described with respect to FIG. 9 below. T-gates 18 can also be implemented as field effect transistor (FET) switches. Such switches will pass, when on, approximately 25 ohms resistance. When off, the FET switches provide an open circuit with approximately infinite resistance. The capacity generated by the off FET switches is approximately 0.3 picofarads at the bond pad. Other implementations for T-gates 18 are possible which would generate different on resistance and off capacity.
As shown in the embodiment of FIGS. 1A and 1B, module select logic 14 provides two signals. These signals operate to turn on T-gates 18 to connect the I/O and address pins to bus 12 when memory module 10 is selected. Conversely, these signals operate to turn off T-gates 18 to disconnect memory module 10 from bus 12 when memory module 10 is not selected. It should be understood that T-gates 18 and the signals from module select logic 14 comprise one embodiment of making memory module 10 selectable and that this function could be implemented in other ways consistent with the teachings of the present invention.
FIG. 2 is a block diagram of one embodiment of pins of a selectable memory module 10 constructed according to the present invention. As shown, memory module 10 includes a plurality of pins 20 which provide gunning transistor logic (GTL) and power/ground pins for memory module 10. In addition, a plurality of pins 22 are LVTTL (low voltage transistor-transistor logic) pins which provide addressing of memory module 10. Other embodiments with alternate pin structures are also possible.
In the embodiment of FIG. 2, the address pins 22 can be used five or six at a time to signal a unique module address. The address pins 22 provide a module address that allows a memory module 10 to be selected to enable interface pins 20. It should be understood that with a 5-pin module address, one of 32 modules can be selected, and with a 6-pin module address, one of 64 modules can be selected. Memory module 10 can further include a broadcast refresh pin, as shown. This pin allows memory module 10 to receive a broadcast refresh signal even though memory module 10 is not currently selected. In this manner, all memory modules can be signaled to refresh without having to be selected. Upon refresh, memory module 10 can, for example, refresh data stored in DRAM cells to maintain data integrity.
FIG. 3 is a block diagram of one embodiment of using module address pins to determine whether or not to select a given memory module according to the teachings of the present invention. As shown in FIG. 3, memory module 10 can include module address compare logic 14 which receives a system clock as well as the memory module address pins. Module address compare logic 14 operates to analyze the memory module address by comparing it to an address associated with the memory module. The module address compare logic 14 then drives a select signal, SELECT, and a select bar signal, SELECT. When the memory module is addressed, the SELECT signal is driven high. Conversely, when the memory module is not addressed, the SELECT signal is driven low. The SELECT and SELECT signals are provided, for example, to the T-gates gates on memory module 10 in order to connect or disconnect memory module 10 from the bus. The module address can be gated by the system clock to insure that turn-off and turn-on of the modules occurs such that only one module is active at the same time. It should be understood that, depending upon the specific application, more than one memory module may need to be selected at one time. This could be accomplished, for example, by giving two or more memory modules the same address.
FIG. 4 is a block diagram of one embodiment of a selected memory module within a bus scheme according to the teachings of the present invention. As shown, a plurality of memory modules 26 are connected to memory sockets 24 which connect to a memory bus 12. In this embodiment, memory bus 12 is terminated by a resistor 28 connected to a power supply. As shown, the middle memory module 26 is currently selected and connected to memory bus 12. In this situation, the other memory modules 26 are isolated from bus 12 and do not load the system bus 12. The only memory module loading the system is the middle memory module 26 while the other memory modules 26 appear as a negligible load on bus 12 (e.g., about 0.1 picofarads). This selectability can provide significant advantages in a system where bus 12 services a large number of memory modules or other integrated circuit assemblies.
FIG. 5 is a block diagram of one embodiment of a module socket 24 constructed according to the teachings of the present invention. Module socket 24 includes select logic 30 which receives memory module address pins and provides the selection signals, S and S. In this embodiment, module selection is handled by each socket location. The particular address for a particular module socket 24 can be, for example, burned into a printed circuit (PC) board at build time or can be hardwired to the board. In this case, the only signals going to the memory module, itself, can be the select, S, and select bar, S, signals. This reduces the number of pins needed on the memory modules.
FIG. 6 is a block diagram of one embodiment of a memory module 32 constructed according to the teachings of the present invention. Memory module 32 includes select logic, indicated generally at 34, that receives memory module address signals and provides the selection signals, S and S. In this embodiment, module selection is handled by each memory module 32. This embodiment adds address compare and decode cost to the memory modules themselves and requires additional pins for addressing the memory module. However, this embodiment would decrease the complexity of the printed circuit board and module socket in which memory module 32 might be installed.
FIG. 7 is a block diagram of another embodiment of a module socket constructed according to the teachings of the present invention. As shown, module socket 36 is connected to select logic, indicated generally at 38, that receives a memory module address and provides the selection signals, S and S. In this embodiment, module selection is handled by select logic 38 built into the printed circuit board at each socket location. This embodiment adds decode costs to the printed circuit board construction but only requires two pins to the memory module. This would reduce the memory module cost and socket connector cost but add to the cost of the board.
FIGS. 8A, 8B and 8C are diagrams of embodiments of bus termination according to the teachings of the present invention. As shown in FIG. 8A, a bus 40 connects to two memory modules 42 where each memory module 42 is selectable in the manner discussed above. FIG. 8B then shows end point termination of bus 40. As shown in FIG. 8B, bus 40 is terminated after passing through all memory modules 42. This end point termination is shown generally at 44. In the embodiment of FIG. 8B, the termination is accomplished using a 50 ohm resistor 46 which is then connected to a positive power supply, for example, 1.2 volts.
FIG. 8C shows an alternative local termination for bus 40 at each memory module 42. As shown in FIG. 8C, two sets of switches, indicated generally at 48, receive the module selection signals, SELECT and SELECT. When the associated module is selected, the module is connected to bus 40 by one set of switches 48. Alternatively, when the module is not selected, bus 40 is locally terminated by connection to a resistor 50, for example, 50 ohms, which is then connected to a positive power supply, for example, 1.2 volts.
The termination method provided by FIG. 8B provides efficient termination of bus 40, however, such end point termination can add stub noise to the signal. The embodiment of FIG. 8C is also an efficient means for termination. However, such local termination can add approximately 25 ohms to the path in each module location.
FIG. 9 is a circuit diagram of one embodiment of a switch, indicated generally at 52, used to select an integrated circuit assembly according to the teachings of the present invention. As shown, switch 52 connects between a first pad 54 and a second pad 56, which comprise bond pads connecting between the bus and the integrated circuit assembly. Switch 52 is built from an NPN bipolar transistor. 58 and a PNP bipolar transistor 60. NPN transistor 58 receives a module selection signal, SELECT PNP transistor 60 receives an inverse module selection signal, SELECT. As can be seen, when the assembly is to be selected (SELECT is high and SELECT is low), both NPN transistor 58 and PNP transistor 60 will turn on and connect pad 54 to pad 56. Conversely, when the selection signal is low, NPN transistor 58 and PNP transistor 60 will turn off, thus disconnecting pad 54 from pad 56. In one embodiment, bipolar transistors 58 and 60 can be constructed from silicon or gallium arsenide to provide high speed switching between pads 54 and 56.
FIG. 10 is a cross section diagram of one embodiment of a bond pad for an integrated circuit constructed according to the teachings of the present invention. As shown, pad 62 is built upon a silicon substrate 64 having an N+ doped region 68. An oxide layer 70 is formed above silicon substrate 64 and N+region 68. A first metal layer 72 and a second metal layer 74 are then used to construct a connecting surface for pad 62. Lastly, an oxide layer 76 is formed over the structure to protect the integrated circuit. Pad 62 of FIG. 10 can be constructed as a 125×125 millimeter bond pad which can yield approximately 0.3 picofarads of capacitance. If the pad is reduced using a tab bond to 0.85 per side, the capacitance can be reduced to approximately 0.125 or 0.2 picofarads. It should be understood that the process for building a bond pad for an integrated circuit can vary and can be accomplished in a manner different from that shown in FIG. 10.
FIG. 11 is a block diagram of one embodiment of a memory module 78 and memory module socket 80 constructed according to the teachings of the present invention. Memory module 78 includes a plurality of memory devices 81 and a plurality of interconnect devices 82. Each interconnect device 82 comprises a plurality of upper bond pads 84 and lower bond pads 86. Each interconnect device 82 also includes a plurality of selection signal terminals 88 for the signals s and S. Bond pads 84 and 86 are used by interconnect device 82 to connect pins of memory module 78 with memory devices 81 and with other devices on memory module 78. As shown, a pitch 90 of bond pads 84 and 86 can match module connector pins within module socket 80.
Within each interconnect device 82 of FIG. 11 there is an integrated circuit containing a plurality of transistors 92. The transistors 92 can be paired as an NPN bipolar transistor 92 and a PNP bipolar transistor 93 for each pair of upper and lower bond pads 84 and 86. NPN transistor 92 comprises a base 94 connected to the S signal, and PNP transistor 93 comprises a base 96 connected to the S signal. NPN transistor 92 further comprises a collector 98 and an emitter 100. Similarly, PNP transistor 93 comprises a collector 102 and an emitter 104. Alternately, the transistors 92 could be field effect transistors (FET) or other forms of switches.
When the appropriate select signals are presented on bond pads 88, those signals are carried to transistors 92 to connect bond pad 84 with bond pad 86. In the illustrated embodiment, the signals from bond pads 88 are carried to the base of bipolar transistors 92 and 93. Alternatively, those signals are carried to the gates of field effect transistors or to control terminals of other types of switches. As can be seen, the connection between upper bond pads 84 and lower bond pads 86 can thereby be selectably controlled. When bond pads 84 and 86 are connected, memory devices 81 and other devices on memory module 78 are connected to the signals received by memory module socket 80. This allows memory module 78 to be active within the system. Conversely, when bond pads 84 and 86 are not connected, memory module 78 is inactive and disconnected from socket 80. It should be understood that implementations other than that if FIG. 11 are possible to provide selectability of integrated circuit assemblies consistent with the teachings of the present invention.
Although the present invention has been described in detail, it should be understood that various changes, substitutions and alterations can be made thereto without departing from the spirit and scope of the invention as defined by the appended claims.
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According to one aspect of the present invention, a selectable integrated circuit assembly (10) is disclosed. The assembly includes a first plurality of terminals (20) for communicating information to and from an integrated circuit device and a second plurality of terminals (22) for receiving an assembly address. The assembly (10) also includes select logic (14) connected to receive the assembly address and operable to generate select signals based upon the assembly address. The select signals have a selected state and a not-selected state. A plurality of switches (18) are connected between the first plurality of terminals (20) and the integrated circuit device. The plurality of switches (18) are connected to receive the select signals. The switches (18) operate, when the select signals are in the selected state, to connect the first plurality of terminals (20) to the integrated circuit device. When the select signals are in the non-selected state, the switches (18) operate to disconnect the first plurality of terminals (20) from the integrated circuit device. According to one embodiment of the present invention, the assembly is a selectable memory module (10).
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BACKGROUND OF THE INVENTION
The present invention relates to a pitching machine, and more particularly to such a machine which has a variety of pitching styles such as fastballs, curve balls, sliders, etc.
A prior art pitching machine, as shown in Japanese Design Patent No. 363,180, has two rotating discs. Balls are supplied in between these discs and thrown out therefrom.
According to the prior art, the outer circumferential parts of the rotating discs are made of urethane, whose frictional force is used to throw the balls. In use, however, the urethane is worn off and the distance between the discs changes. If such change is left as it is, the pitching becomes unsteady and balls may be thrown in unexpected directions. Because of this a problem arises in that the distance between the discs must be adjusted if the outer circumference of the urethane becomes worn.
A further problem in the prior art is that the desired pitching is unavailable unless balls are correctly supplied between the rotating discs.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a pitching machine which facilitates adjustment of the distance between ball-throwing rotary discs.
Another object of the present invention is to provide a pitching machine which can steadily feed balls in between ball-throwing rotary discs even if the machine body is tilted during operation, thereby assuring the desired pitching style.
Still another object of the present invention is to provide a ball feed mechanism which can keep many balls in a storage chamber and pitch the balls consecutively, and if connected via a flexible hose to a pitching mechanism, the ball feed mechanism can be set anywhere within the reach of the hose.
According to the present invention, there is provided a pitching machine comprising: two parallel rotary shafts projecting from a machine housing; rotary discs mounted on said rotary shafts with the outer circumferences being made of urethane; an adjustment mechanism inside the housing for adjusting the distance between the rotary shafts; a drive mechanism capable of the selecting rotational direction and rotational frequency of said rotary shafts; and a ball feed mechanism interposed between said rotary discs, said ball feed mechanism comprising a cylindrical feed body whose outlet is interposed between the rotary discs, a piston provided in said feed body and reciprocating relative to said outlet, and a ball supply tube provided in the side of the feed body and communicating therewith, so that the desired ball pitching is assured.
According to another aspect of the present invention, there is provided a ball feed mechanism comprising a ball supply tube having an opening in the top, a ball feed tube having an opening in the top, a ball feed tube having both ends open and provided at the lower end of said supply tube in a perpendicular relation with the axis of said ball supply tube, said ball feed tube being connected at one end to a blow port of an electric blower mounted on a body and at the other end to a flexible hose reaching at a pitching mechanism, a slider having a hole of the same diameter as the opening of said ball supply tube and being capable of horizontal reciprocation, and a storage chamber located above said slider and mounted to the body, for keeping many balls and supplying balls one by one toward said slider.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a top plan view of a pitching machine in accordance with an embodiment of the present invention;
FIG. 2 is a vertical sectional view of the pitching machine of FIG. 1;
FIG. 3 is a vertical sectional view of a ball feed mechanism used in the embodiment of FIG. 1;
FIG. 4 is a top plan view of the ball feed mechanism;
FIGS. 5 show a piston which is a part of the ball feed mechanism, with FIG. 5A being a top plan view and FIG. 5B being a front view thereof;
FIG. 6 is a vertical sectional view of ball feed mechanism in accordance with another embodiment of the invention;
FIG. 7 is a sectional view taken along line VII--VII of FIG. 6;
FIG. 8 is a top plan view of a ball-feeding flexible hose shown in FIG. 6 and the pitching machine connected therewith;
FIG. 9 is a front view of a target used in experiments; and
FIG. 10A to 10H are schematic representations showing how the pitching machine is used.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
With initial reference to FIGS. 1 and 2, a pitching machine in accordance with an embodiment of the present invention includes a box-shaped housing 1, from which two rotary shafts 2 project. Discs 3 are coplanar and are fixed, via keys 4, on the projecting portions of the rotary shafts 2. Discs 3 are fitted with urethane members 5 on the outer circumferences thereof so as to form urethane wheels 6.
Each of the rotary shafts 2 is mounted by bearing blocks 7 which are disposed outside of the housing 1, and the bearing blocks 7 are integral with bearing mounting plates 8 which are disposed inside the housing 1. At least on one side of the housing 1, the bearing mounting plates 8, together with the bearing blocks 7, are mounted to be moveable in a direction perpendicular to the longitudinal direction of the rotary shaft 2.
Lips 9 are formed on the bearing mounting plates 8 (those on the left side in FIG. 2) and shaft members 10 are rotatably mounted via bearings. Shaft members 10 extend in the direction perpendicular to the (left-side) rotary shaft 2, that is, in the direction of movement of the bearing mounting plates 8. Sprocket wheels 11 and photo-sensor discs 12 are provided on the shaft members 10 and located on opposite sides of the lips 9. Although not illustrated, each disc 12 has a plurality of openings and is disposed between a light source and a light detector so that the rotational angle of the respective shaft member 10 can be detected. The shaft members 10 are formed as screw rods 13 at least at the ends thereof.
The other bearing mounting plates 8 (on the right side in FIG. 2) are formed with lips 14, in which auxiliary adjustment screw rods 15 are engaged perpendicularly to the (right-side) rotary shaft 2. The auxiliary adjustment screw rods 15 are provided with nuts 16 which, in turn, are engaged with the screw rod portions 13 of the shaft members 10. Numerals 17 indicate limit switch discs provided on the auxiliary adjustment screw rods 15 and numerals 18 indicate nuts for fixing the auxiliary adjustment screw rods 15 to the lips 14.
A motor 19 has a sprocket wheel 20 on its drive shaft, and a chain 21 is mounted around the sprocket wheel 20 and the sprocket wheels 11 of the shaft members 10 so that, when the sprocket 20 wheel is rotated by the motor 19, the shaft members 10 are rotated and moved axially. This axial movement displaces the rotary shaft 2 together with the lips 9 and the bearing mounting plates 8, thereby adjusting the distance between the urethane wheels 6. While motor 10 is shown between shaft members 10 in FIG. 2, it is mounted at a position spaced apart from a plane running through shaft members 10 and hence the sprocket wheel 21 is separated from the sprocket wheels 11 by a distance which is sufficient to permit chain 21 to remain in engagement with the sprocket wheels despite the axial displacement of the shaft members 10.
Pulleys 22 are mounted on the rotary shafts 2 and are linked by belts 25 with driving motors 26 so as to rotate the urethane wheels 6, the belts 25 and motors 26 being shown only schematically. Because the left and right rotary shafts 2 may need to be rotated at different rotational speeds, they are driven by two separate motors.
Since the left and right urethane wheels 6 are driven independently, it is possible to rotate them at the same or different rotational speeds or angular velocities. The urethane wheels 6 are arranged to be apart from each other by a distance a little smaller than the ball diameter, and the left one is adapted to rotate counterclockwise while the right one rotates clockwise.
When a ball is supplied in between the urethane wheels 6, the ball will be sprung out by a strong force therefrom. By selecting the orientation and angle of inclination of the housing 1 and the rotational speed of the urethane wheels 6, the desired pitching style is available.
Next, a ball feed mechanism will be described with reference to FIGS. 3 to 5.
A feed body 30 for the ball feed mechanism is cylindrical and open at one end, where an outlet 31 is formed with the sides being cut in a taper. The outlet 31 is located midway between the urethane wheels 6. The feed body 30 has mounting legs 32 on its lower side and is secured thereby to the housing 1. A ball supply tube 33 vertically protrudes from the feed body 30 and has an opening in the top from which balls are supplied. A piston 34 is housed in the feed body 30 so as to retract behind the rear of the supply tube 33 and advance toward the outlet 31. A toothed rack 35 forms a piston rod for the piston 34. Numeral 36 indicates a linear head having a drive pinion (not shown) which meshes with rack 35. Numeral 38 indicates a motor, and numeral 37 indicates a gear head which receives power from motor 38 and rotates the drive pinion in linear head 36 at a relatively slow speed. The drive from the motor 38 causes the rack 35 to move back and forth, thereby reciprocating the piston 34.
To stabilize the engagement of the rack gear 35 with its associated drive pinion, the piston 34 is provided with bearings 39 on opposite sides thereof. Bearings 39 are received in guide slots 40 formed longitudinally along the side of the feed body 30.
A ball stopper 41 is provided between the supply tube 33 and the outlet 31. The stopper 41 has a ball member 42 which protrudes inwardly of the feed body 30 and is mounted to be movable up and down by a mounting screw 43. A spring 45 is disposed between a collar 44 for the mounting screw 43 and the ball member 42. The ball member 42 protrudes into the feed body 30 except when a ball is being forced out by piston 34.
With the piston 34 being retracted within the feed body 30, a ball is inserted through the supply tube 33 into the feed body 30. Then the motor 38 is driven to advance the piston 34 toward the outlet 31, whereupon the ball proceeds against the stopper 41 and is fed from the outlet 31 in between the urethane wheels 6 and, as was mentioned previously, the ball is thrown out from between the rotating wheels 6.
Further, protection covers 50 (see FIG. 1) are provided on the top of the housing 1 so as to cover a portion of the circumference of the urethane wheels 6.
Another ball feed mechanism will now be described with reference to FIGS. 6-8.
A chassis 100 for this ball feed mechanism is movable on casters 101. The chassis 100 is provided with a top-open supply tube 102 and, thereunder, a feed tube 103 extending perpendicular to an axis of the supply tube 102. The feed tube 103 is open on both ends, and one end is connected to a blow port 105 of an electric blower 104 while the other is connected through a hose joint 106 to a flexible hose 106 which extends to the pitching machine.
The upper opening of the supply tube 102 is formed with a rack plate 108, on which a slider 109 is adapted to move horizontally. The slider 109 has an opening 110 of the same diameter as the opening in the supply tube 102, and a plate 111 for closing an outlet of a ball storage chamber 114 to be described later. The slider 109 is fixed to a toothed rack 113 which is driven by a reciprocating mechanism 112 which, although not illustrated, includes a motor, speed-reduction gearing, and a drive pinion which meshes with rack 113.
The storage chamber 114 is mounted on the chassis 100 so that it is superposed on the slider 109 and mounted so that it is movable in the direction perpendicular to the slider movement. The storage chamber 114 is divided into a plurality of compartments 116, each having space for housing approximately ten balls 115. The upper end of the storage chamber 114 is formed as a funnel-shaped guide inlet 117 and the lower end is formed as a tapering outlet 118. Lower and upper slide mechanisms 119 are provided behind the storage chamber 114 so as to allow it to slide back and forth in the horizontal direction. A screw rod 120, which is mounted between the slide mechanisms 119 and rotated by a driving motor 121, permits the storage chamber 114 to move back and forth in the axial direction of the screw rod 120.
Every compartment 116 of the storage chamber 114 is open at the lower end, but a partition 122 provided on the chassis 100 closes the opening to prevent balls from falling down. The partition 122 has an opening 123 at a position corresponding to the slider 109, and when the opening 123 is aligned with one of the compartments 116, a ball in such compartment is supplied into the supply tube 102.
In order to feed a ball 115 to the urethane wheels 6 on the housing 1, a feed nozzle 124 having a tip end with both sides tapered is located in between the urethane wheels 6, and the feed nozzle 124 is connected to the flexible hose 107 which is connected to the feed tube 103.
In the above-constructed ball supply mechanism of the present pitching machine, the urethane wheels 6 rotate in opposite directions to each other and the electric blower 104 is actuated to supply pressurized air to the feed tube 103, the flexible hose 104, and the feed nozzle 124. When a ball 115 is supplied to the supply tube 102, the ball is sent to the feed tube 103 and at the same time carried by the pressurized air from the blower 104 through the flexible hose 107 into the feed nozzle 124. Feed nozzle 124 inserts the ball between the urethane wheels 6, which then pitch the ball at the desired speed and in the desired manner.
While the pitching machine is in operation, the slider 109 has a "waiting" position such that the opening 110 is located over rack plate 108 of the supply tube 102, permitting a ball 115 from the storage chamber 114 to be kept in the opening 110. When a person gets ready to bat, the reciprocating mechanism 112 is actuated to move the slider 109 via the rack 113. Once the opening 110 comes into alignment with the supply tube 102, the ball 115 falls down into the supply tube 102 and then reaches the feed tube 103, where the ball is carried away to the feed nozzle 124 by the pressurized air from the blower 104.
When the slider 109 is displaced to drop a ball 115 into the supply tube 102, the slider plate 111 closes the opening 123 in the partition 122 and therefore prevents the balls 115 in the storage chamber 114 from falling down. After delivering a ball 115 to the supply tube 102, the slider 109 returns to the "waiting" position and another ball is received into the opening 110. The slider 109 stops at the "waiting" position, thereby completing one cycle of operation.
When all balls 115 in one compartment 116 are consumed, the screw rod 120 is rotated by the driving motor 121 until the next compartment 116 comes in alignment with the opening 123 of the partition 122. The ball feed mechanism may be resupplied by loading balls when one compartment 116 or all compartments 116 are empty of balls.
Examples of Experiment
As shown in FIG. 9, a 430 mm-wide by 750 mm-long board was divided into nine equal parts. The center portion, indicated by reference character E (144.3 mm wide and 250 mm long), was used as the strike zone. The present pitching machine was placed 18.44 m from this board.
As shown in FIG. 10A, the housing 1 was oriented so that the urethane wheels 6 were vertically disposed, and the upper wheel was rotated at 1200 rpm while the lower one was rotated at 2340 rpm. Balls were fed in between these wheels 6 and pitched as straight fastballs toward the target. Hardtype balls 74 mm in diameter were used.
The test results of pitching balls toward the strike zone (reference character E) under the above-described condition were as follows.
With the wheels 54 mm apart:
48 balls were pitched and 26 of them hit the strike zone E. The hitting rate or accuracy was 54% and the average ball speed was 112.3 km/H.
With the wheels 52 mm apart:
48 balls were pitched and 46 of them hit the strike zone E. The hitting rate was 96% and the average ball speed was 34.0 km/H.
With the wheels 50 mm apart:
48 balls were pitched and all of them hit the strike zone E. The hitting rate 100% and the average ball speed was 38.7 km/H.
The above test results proved that it is easy to control balls and provide a high hitting rate if the urethane wheels 6 are separated by a gap of 50 mm to 52 mm. Further, it was found that the faster the wheels are rotated, the higher the ball speed becomes, and vice versa. A variety of pitching styles are available by selecting the rotational speed of the left and right wheels and by changing the angle of inclination of the housing.
FIGS. 10A through 10H show applications of the pitching machine, all of them for a right-handed batter. Every drawing is seen from the ball feed side.
FIG. 10A is for a straight fastball.
FIG. 10B is for a ball that veers upward from right to left (a slider of an underhand pitcher).
FIG. 10C is for a slider that veers right to left.
FIG. 10D is for a curve ball.
FIG. 10E is for a curve ball that drops vertically (a drop ball).
FIG. 10F is for a shoot ball.
FIG. 10G is for a ball that veers from left to right (a slider).
FIG. 10H is for a knuckle ball or fork ball.
Because the urethane wheels 6 throw the balls while pressing them tightly, the center portions of the wheels will be worn off according to the ball shape. When this occurs, the sides of the urethane wheels 6 should be ground to flatten them.
Furthermore the distance between the urethane wheels 6 should be adjusted by driving the motor 19 to move the shaft members 10 axially and draw together the rotary shafts 2 and the bearing blocks 7.
The present disclosure relates to the subject matter disclosed in Japanese application 62-144,844 of Sept. 22nd, 1987, Japanese application 62-19502 of Jan. 28th, 1987, and Japanese Utility Model application 62-17558 of Feb. 9th, 1987, the entire disclosures of which are incorporated herein by reference.
It will be understood that the above description of the present invention is susceptible to various modifications, changes, and adaptations, and the same are intended to be comprehended within the meaning and range of equivalents of the appended claims.
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A machine for pitching baseballs includes two discs which are mounted on independently rotatable shafts. The discs have urethane at their peripheries. The spacing between the shafts can be adjusted in order to set the width of a gap between the discs. A ball feed mechanism inserts balls into the gap between the discs, which then fling the balls outward in a pitching style which depends upon the orientation of the pitching machine and the relative rotational speeds of the discs. In one embodiment, the ball feed mechanism employs a tubular feed body having a tapered outlet end which is positioned adjacent the gap. A piston in the feed body reciprocates to push the balls out. In another embodiment, the ball feed mechanism is mounted on a chassis having casters and is connected via a flexible hose to a feed nozzle positioned adjacent the gap. A reciprocating slider transfers balls from a storage chamber to an inverted-T tube arrangement, whence they are blown pneumatically through the hose to the feed nozzle.
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BACKGROUND OF THE INVENTION
1. Field of The Invention
The present invention relates to the use of methyl benzoate as an additive to sewage to reduce the generation of hydrogen sulfide in an enclosure where humans may be exposed to the hydrogen sulfide. In particular, the present invention relates to the use of methyl benzoate in a dilute aqueous emulsion as an additive to the sewage.
2. Description of Related Art
Methyl benzoate is sold commercially under the trademark ZING by Zing Agricultural Product Applications, Inc., Portland, Mich., as an aqueous emulsion for odor control in sewage and livestock manure. The emulsifier is a small volume of a non-toxic soap or detergent which allows the methyl benzoate to be mixed with water. This product is also used to dissolve and control grease, sludge, soap and detergent deposits, particularly in drains and sink traps. It is approved under EPA regulations and is considered safe for use in the environment.
The municipal treatment of raw sewage to separate water and a sludge is well known to those skilled in the art. It is described in detail in Kirk Othmer 24 407 to 418 (1984) and in numerous other publications on the subject. The process generally involves sewage pumping, settling and biological treatment in various forms. In general, the process equipment is housed in an enclosure in which humans at least periodically have to work.
Hydrogen sulfide is generated from sewage in amounts which are dangerous to humans and which can be fatal. The method of the prior art method for removing hydrogen sulfide is to vent the gas to the atmosphere. The smell is unpleasant (rotten egg odor) and persons around the enclosure, particularly downwind, can become sick with headaches, rashes and the like. Since hydrogen sulfide is an acid, it is corrosive to equipment. There is a need for the reduction of the hydrogen sulfide generated by the sewage.
Hydrogen sulfide gas is a dangerous problem in sewage treatment plants. Under OSHA rules in the U.S. (29 CFR 1910.1000), the time weighted average (TWA) for an employee in an eight hour shift for a 40 hour work week for hydrogen sulfide is 10 ppm (14 rag/m 3 ). The short term exposure limit (STEL) at any time during a work week is 15 ppm (21 mg/m 3 ). As can be seen, hydrogen sulfide is quite poisonous and presents a significant health risk for workmen.
OBJECTS
It is therefore an object of the present invention to provide a novel method and compositions for treating the sewage to very significantly reduce the generation of hydrogen sulfide in enclosures in which humans must work. Further, it is an object to provide a method which is simple and economical. These and other objects will become increasingly apparent by reference to the following description.
DESCRIPTION OF PREFERRED EMBODIMENTS
The present invention relates to a method for reducing hydrogen sulfide in an enclosure housing equipment in which sewage is to be processed and in which humans at least periodically work which comprises: admixing methyl benzoate in the sewage in an amount which reduces the hydrogen sulfide in the enclosure. The enclosure can be a sewage pumping substation or a sewage treatment plant for instance. A composition including the methyl benzoate in an amount between about 1 to 10% by volume and about three-tenths (0.3) or less of this amount of an emulsifier is preferably added in an amount between about 0.01×10 -3 to 0.5×10 -3 part per part by volume of the sewage.
Further, the present invention relates to a method for reducing hydrogen sulfide in a sewage treatment plant including an influent of sewage into the plant settling tank, means for microbial treatment of the sewage after the settling tank and a liquid effluent and a treated sewage which are removed from the plant which comprises adding an amount of a composition which is an aqueous emulsion of methyl benzoate to the sewage so as to reduce the hydrogen sulfide in the plant. The aqueous emulsion of the methyl benzoate can be added in the influent to the plant, settling tank(s) or it can be added to equipment for microbial treatment of the sewage to reduce the hydrogen sulfide.
Finally the present invention relates to a composition adapted for sewage treatment to reduce hydrogen sulfide when mixed with water which comprises: methyl benzoate; and a polyoxyethylene derivative of a sorbitan fatty acid ester, wherein the ratio by volume of (a) to (b) is between about 1 to 1 and 20 to 1, wherein the composition when added to sewage reduces hydrogen sulfide.
It is preferred to use an emulsifier with water and the methyl benzoate to provide a composition for treatment of the sewage. The most preferred emulsifiers are polyoxyethylene derivatives of sorbitan fatty acid esters which are non-ionic surfactants. Most preferred is TWEEN 20, which is polyoxyethylene 20/sorbitan monolaurate manufactured by ICI Americas, Inc., located in Spartanburg, S.C. This emulsifier has a hydrophile-lipophile balance (HLB) value of 16.9 out of 20 which means that it is hydrophilic. Preferably the range of HLB is between about 10 and 19.
The preferred aqueous compositions include
______________________________________(1) Methyl benzoate 9.6 oz (283.7 cc) TWEEN 20 emulsifier 2 oz (59.14 cc) Water 1 gallon (3.78 liters)______________________________________
With 116.4 oz (3.44 liters) of water then added per gallon subsequently
This provides about 3.9% methyl benzoate and 0.82% of the emulsifier in the finished composition, by volume.
______________________________________(2) Methyl benzoate 15 oz (443.5 cc) TWEEN 20 emulsifier 2 oz (59.14 cc) Water 1 gallon (3.78 liters)______________________________________With 111.4 oz (3.28 liters) of water then addedper gallon subsequently
This provides about 6.3% methyl benzoate and about 0.84% of the emulsifier in the finished composition, by volume.
______________________________________(3) Methyl benzoate 5 oz (147.6 liters) TWEEN 20 emulsifier 1 oz (29.57 cc) Water 1 gallon (3.78 liters)______________________________________
With 121 oz (3.57 liters) of water then added per gallon subsequently.
This provides about 2.0% of the methyl benzoate and about 0.4% emulsifier in the finished composition, by volume.
The concentrate, before further water is added, is produced in a large, closed vessel having a propeller mixer with the ingredients under pressure (1100 psig) for thirty (30) minutes. The water is then added to produce composition (1), (2) or (3). For sewage treatment it was found that composition (2) was preferred. The compositions are preferably added in a ratio to the sewage by volume of between about 0.05×10 -3 to 0.125×10 -3 part of the composition per part of the sewage.
The methyl benzoate is preferably used in a volume ratio to emulsifier of between about 1 to 1 and 20 to 1. The methyl benzoate is preferably used in water in a ratio between about 1 to 100 and 1 to 4.
EXAMPLE 1
Testing was conducted for hydrogen sulfide odors at a substation for a waste water treatment plant. The substation was a large underground sewagestorage area that collected waste from the surrounding facilities and pumped it to the waste water treatment plant.
Before workmen could enter the substation, the building was opened up and fans were turned on to try to dissipate the hydrogen sulfide. A hydrogen sulfide gas testing gauge was used to check the air before entering. At first the meter read 160 ppm before entering. Federal law dictates a reading should be 7 ppm (400 ppm on the scale being deadly). The device initially read about 75 ppm upon entering. Composition (2) above was addedto the waste in an amount of about 0.05×10 -3 part per part of the sewage by volume and the reading on the gas meter immediately dropped to 35 ppm. Within ten minutes of application and the gas meter was down toonly 5 ppm. The methane gas and odors were also reduced.
EXAMPLE 2
The composition (2) was added to a tank (polymer tank) which directly feedsa thickener tank with a sewage settling polymer in a sewage treatment plantin an amount of about 0.05×10 -3 part per part of the sewage by volume. There was a significant reduction of hydrogen sulfide and odor in the tank and in belt presses which are used to remove the sludge from the tanks.
EXAMPLE 3
The composition (2) was added to a scum concentrator which is an overflow system for removing scum from settling tanks. The amount added was about 0.1×10 -3 part of the composition (2) per part of the sewage by volume. There was an elimination of the odor and gas concentrations immediately. It is forecast that the reduction in hydrogen sulfide will reduce equipment replacement costs because of corrosion from hydrogen sulfide.
The mechanism for the reduction of hydrogen sulfide by methyl benzoate is not understood. It is speculated that the microorganisms in the sewage maypreferentially metabolize the methyl benzoate in a manner which does not generate hydrogen sulfide.
The foregoing description is only illustrative of the present invention andthe present invention is limited only by the hereinafter appended claims.
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A method for the reduction of hydrogen sulfide in an enclosure which is involved in processing sewage and where workmen are present wherein methyl benzoate is used an additive to the sewage is described. The methyl benzoate is preferably in the form of a dilute aqueous emulsion. The emulsifier is preferably a polyoxyethylene derivative of a sorbitan fatty acid ester and most preferably, polyoxyethylene (20) sorbitan monolaurate.
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The invention herein described was made in the course of or under a contract or subcontract thereunder with the Department of the Army.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to hydraulic dampers of the cylinder and piston type used for controlling the fore and aft movement of helicopter rotor blades in their plane of rotation. More particularly, this invention relates to means for providing redundant seals, a fluid reservoir, and a means for accurately indicating when the seals for the damper have become worn and are leaking excessively; all in a closely contained system.
2. Description of the Prior Art
Dual seals have been used on the shafts of dampers and servomotors and the like with fluid pressure indicators connected to the area between seals to indicate leakage past the primary seal. U.S. Pat. No. 1,943,578, issued January 16, 1934 to G. E. Bigelow et al shows such an arrangement applied to a high pressure centrifugal pump shaft. The area between the seals is connected by a conduit containing a restriction (valve) to a low pressure system and a pressure gage is connected to the conduit between the restriction and the seals. This arrangement proved objectionable because a pressure built up in the return line for the leakage fluid, thereby giving a false indication of leakage. In addition, this arrangement requires the use of external fluid lines, a separate reservoir and a pump to collect the fluie leakage and return it to the high pressure system. This arrangement is not optimally suited to a helicopter rotor application as the added complexity would hamper performance and limit reliability as well as increase cost and weight.
RELATED APPLICATIONS
An application of G. Bochnak, Ser. No. 584,237, and issued Aug. 3, 1976 as U.S. Pat. No. 3,972,396 filed concurrently with this application, shows a leaked-fluid indicator in an hydraulic system in which the difficulty of back pressure causing a false indication has been successfully overcome, but not within a closed, self-contained system exclusive of external lines, reservoir and pump.
SUMMARY OF THE INVENTION
It is an object of this invention to provide a hydraulic damper for controlling the lag-lead movements of helicopter rotor blades which greatly extends the service life of the damper between seal replacements.
More particularly it is an object of this invention to provide a damper of the cylinder and piston type in which the piston rods are provided with spaced primary and secondary seals for redundancy and means is provided for collecting fluid which leaks past the primary seals, conveying it to a closed reservoir provided with a fluid level indicator, and then returning the leaked fluid to the damper chambers by means of a shuttle valve, using the pumping action of the damper itself rather than an external or secondary pump.
A still further object of this invention is to provide a self-contained hydraulic damper which is sealed for life, requires no maintenance, and exhibits high reliability.
A yet further object of this invention is generally to improve the construction and performance of hydraulic dampers, absorbers, attenuators and similarly acting devices.
BRIEF DESCRIPTION OF THE DRAWING
The single FIGURE is a diagrammatic sectional showing of the improved damper and its leaked-fluid control system.
DESCRIPTION OF THE PREFERRED EMBODIMENT
In the drawing, 10 indicates the casing of the hydraulic damper and 12 indicates a piston reciprocable therein having a piston rod 14 that extends on opposite sides of the piston through the left and right-hand cylinder walls 16 and 18. It will be understood that the piston rod 14 has at its right-hand extremity an eye (not shown) by which it is connected to a helicopter rotor blade. The damper casing 10 is likewise extended at its other extremity and terminates in a similar eye (not shown) which is pivotally connected to the rotor head. This structure is shown in the copending Bochnak application, previously mentioned, and reference is made thereto for a showing of the damper installation details. Damper piston 12 has the usual restriction 20 permitting limited fluid flow between damper chambers 22, 24 as the piston reciprocates relative to casing 10. Oppositely opening pressure relief valves 26, 28 are provided which open upon opposite movements of the piston under excessive pressure conditions in the chambers.
End walls 16, 18 of the damper casing are each provided with spaced primary and secondary, i.e., first and second, seals 30, 32 about piston rod 14 with a small annular cavity 34 surrounding rod 14. These cavities are provided to collect fluid which leaks past primary seals 30 during operation of the damper. Cavities 34 are connected by a cored passage 36 which includes restriction 37 and which communicates with another cored passage 66 leading to inlet chamber 68 of a shuttle valve 52 in the damper casing and thence through cored passage 38 to reservoir 40. Reservoir 40 is a part of the damper indicator generally indicated at 41 and is closed by a diaphragm 42 which carries a fluid level indicator 44. A compression spring 46 surrounding indicator member 44 rests at one end on a cover 48 and at its other end on member 44, thus exerting pressure against diaphragm 42 to maintain a slight pressure in the leaked fluid at all times. This serves amoung other things to assure lubrication of seals 30, 32. Piston 12, shuttle valve 52, and reservoir 40 of damper indicator 41 are herein all contained within damper casing 10, forming a compact, self-contained, completely closed unit without external sumps and pumps which is particularly important when it is considered that as many as seven damper units must be located between as many blades and the rotor hub of some present day helicopters.
As the damper moves, for example, to the left as indicated by the arrow, pressure in chamber 22 is increased and this increased pressure is transmitted through conduit 50 to shuttle valve 52 which is enclosed in a cored chamber within damper chamber casing 10. A similar conduit 53 connects the right-hand chamber 24 with the shuttle valve. The shuttle valve is a spool valve comprising essentially two spaced value members 54, 56 connected by a short shaft 58 and seating on alternately engageable seats 60, 62 respectively as the shuttle valve is reciprocated by pressure from damper chambers 22, 24. The shuttle valve has a central fluid port 64 which is connected by cored passage 66 with passage 36 containing leaked fluid. Fluid entering the shuttle valve through port 64 flows into central chamber 68 and, depending upon which valve member is off its seat, flows through splined openings 70 in the open valve member into radial passages 72 and thence through the axial passages 74, 75 into conduit 50 or 53. The shuttle valve is symmetrical so it is unnecessary to trace the flow in the opposite direction.
In the normal operation of the damper system above described, the primary seals 30 will feel the full damper pressure during the first phase of its service life. Normal seal wear will eventually allow some slight amount of fluid, usually oil, to weep past this seal into the annular areas, or cavities, 34 between the primary and the secondary seals. This weepage is not lost from the damper system since annulus 34 is connected to reservoir 40 of the indicator via conduits 36, 66, 38. Thus, it will be noted, a closed damper system is provided. Throughout the normal life of the primary seals this weepage will gradually increase in rate and will continue to be returned to the reservoir at the same low pressure as long as the primary seal can hold back the high damper pressure. During the lifetime of the primary seals the secondary seals will wear at a very much reduced rate or perhaps not at all since they feel only the very low pressure supplied by spring 46 and are lubricated by fluid from reservoir 40.
When a primary seal finally fails and it can no longer support the damper pressure, fluid flow past the primary seal will increase to the extent that restrictor 37 will cause the damper pressure of chambers 22, 24 to build up and be felt by secondary seals 32. Thus the last phase of the damper service life begins. The secondary seal, when it is finally called upon, will be, for all intents and purposes, new and it will have remaining a 100% useful life. When in due course the secondary seal wears sufficiently to allow leakage, fluid will then be lost from the system by leakage past the secondary seal to atmosphere at, for example, point 80. This loss will be made up by the damper indicator as follows: Assuming the damper piston 12 to be moving to the left, fluid under high pressure will flow through passage 50 to shuttle valve 52 causing valve 54 to engage its seat 60. As the damper piston compresses the fluid in chamber 22, the pressure in chamber 24 will be reduced. Fluid supplied by reservoir 40 will then flow through passage 38, enter port 64 and flow through valve member 56, which is open, through splined passages 70 into radial passages 72 and thence out through axial passages 74, 75 into conduit 53 and into damper chamber 24. Similarly oil will be supplied to chamber 22 when the damper piston moves to the right. The slight positive pressure maintained on the low pressure side of piston 14 by reservoir 40 will prevent any air from being drawn into damper chambers 22, 24 past failed seals 32, 30. Any air in damper chambers 22, 24 would adversely affect damper performance by producing an irregular force/velocity response.
When sufficient fluid has been lost from the damper system through leakage past the secondary seals, damper indicator 41 will show the need for replenishing the supply of fluid in the system and replacing the seals. The redundant seals 32 at least double the useful life of the damper before maintenance is required. During the first phase of its life while the primary seals are working no fluid is lost from the system and no maintenance is required as at present. During the second phase of its life, fluid lost is automatically replenished from the reserve in the damper indicator 41 and again no maintenance is required. Finally, when both primary and secondary seals have failed and when fluid has diminished the reserve capacity in reservoir 40 to a previously set minimum, indicator member 44 will not show above cover 48. The damper will then be replaced at the first opportunity and sent back to overhaul for seal replacement.
The advantages of the damper system above described are extremely long life, no maintenance during this life, and a damper which in many cases is sealed for its life.
While I have shown and desribed one embodiment of my invention in considerable detail, I do not wish to be limited to the exact details described herein as many modifications will be readily apparent to those skilled in this art which fall within the scope of the following claims.
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A cylinder-and-piston type hydraulic damper has spaced dual seals on its piston rods to provide annular cavities between seals. A fluid leakage line connects said cavities to the closed reservoir of a fluid leakage indicator which consists of a cylinder closed by a spring biased diaphragm which carries the indicating member of the indicator. The damper chambers on opposite sides of the piston are alternately supplied with fluid from the reservoir during operation of the damper by means of a shuttle valve, thus providing a closed and sealed fluid system including redundant seals with means for indicating that the damper needs servicing upon a predetermined loss of fluid from the reservoir.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to gas turbine engines and more particularly to engines having a shroud surrounding the tips of the rotor blades in the turbine section of the engine.
2. Description of the Prior Art
In a gas turbine engine or the type referred to above, pressurized air and fuel are burned in a combustion chamber to add thermal energy to the medium gases flowing therethrough. The effluent from the chamber comprises high temperature gases which are flowed downstream in an annular flow path through the turbine section of the engine. Nozzle guide vanes at the inlet to the turbine direct the medium gases onto a multiplicity of blades which extend radially outward from the engine rotor. An annular shroud which is supported by the turbine case surrounds the tips of the rotor blades to confine the medium gases flowing thereacross to the flow path. The clearance between the blade tips and the shroud is minimized to prevent the leakage of medium gases around the tips of the blades.
A limiting factor in many turbine engine designs is the maximum temperature of the medium gases which can be tolerated in the turbine without adversely limiting the durability of the individual components. The shrouds which surround the tips of the rotor blades are particularly susceptible to thermal damage and a variety of cooling techniques is applied to control the temperature of the material comprising the shroud in the face of high turbine inlet temperatures. In many of these techniques air is bled from the compressor through suitable conduit means to the local area to be cooled. Compressor air is sufficiently high in pressure to cause the air to flow into the local area of the turbine without auxiliary pumping and is sufficiently low in temperature to provide the required cooling capacity.
Most recently, considerable design effort has been expended to minimize the amount of air consumed for cooling of the turbine components. Impingement cooling is one of the more effective techniques utilized and occurs where a high velocity air stream is directed against a component to be cooled. The high velocity stream impinges upon a surface of the component and increases the rate of heat transfer between the component and the cooling air. A second highly effective but not as widely utilized technique is that of transpiration cooling. A cooling medium is allowed to exude at low velocities through a multiplicity of tiny orifices in the wall of the component to be cooled. The low velocity flow adheres to the external surface of the component and is carried axially downstream along the surface by the working medium gases flowing thereacross.
One typical application of transpiration cooling to blade tip shrouds is shown in U.S. Pat. No. 3,365,175 to McDonough et al. entitled "Air Cooled Shroud Seal" . In McDonough et al. a single cooling air chamber extends circumferentially about the outer periphery of the shroud. Cooling air is flowable to the chamber from the compressor section of the engine through suitable supply means to convectively cool the shroud material. At least a portion of the cooling air in McDonough et al. is further flowable to the inner periphery of the shroud through cooling holes of small diameter to introduce cool air into the boundary layer of the hot gas stream adjacent the shroud. One embodiment of McDonough et al, has a multiplicity of grooves or recesses at the inner periphery of the shroud which intercept the cooling holes and prevent the closure of the holes should the blade tips rub against the shroud during operation of the engine. In transpiration cooling the exuding velocities must remain low in order to prevent over penetration of the working medium gases by the cooling air. Over penetration interrupts both the flow of cooling air and the flow of medium gases and renders the cooling ineffective. A preferred pressure ratio across the cooled wall in most transpiration cooled embodiments is approximately 1.25. The effectiveness of a transpiration cooled construction is highly sensitive to variations from the designed pressure ratio across the surface to be cooled; accordingly, the pressure ratio must be closely controlled.
Both cooled and uncooled shrouds are commonly segmented where large variations in thermal expansion between the shroud and its supporting turbine case are expected. A circumferential gap between adjacent segments is provided to allow independent expansion of the case and shroud segments without inducing local stresses. In this type of construction a portion of the medium gases inherently leaks axially through the gap from the upstream to the downstream region of the shroud. A reduction in the amount of leaking gases is effected by providing interlocking lugs at the abutting ends of adjacent segments. U.S. Pat. No. 3,412,977 to Moyer et al. entitled "Segmented Annular Sealing Ring and Method of its Manufacture" shows a shroud having conventionally interlocking lugs. In addition to the interlocking lugs, shroud constructions which are both segmented and cooled require radial sealing means to prevent the wasteful leakage of cooling air from the air chamber into the medium flow path through the gap between adjacent segments. To be effective the radial sealing means must necessarily have a capability for sealing a gap which varies in width according to divergent thermal conditions.
The individual use of the above described cooling techniques and sealing means, although successful in prolonging the life of the turbine components, have proved inadequate to meet today's requirement for durable, high performance engines. More effective ways of utilizing a diminished quantity of cooling air must be found.
SUMMARY OF THE INVENTION
A primary object of the present invention is to improve the performance of a gas turbine engine by reducing the leakage of working medium gases across the tips of the rotor blades. An additional object is to improve the performance and durability of the engine through the judicious use of cooling air to the shroud which surrounds the blade tips.
The present invention is predicated upon the recognition that the performance of a gas turbine engine having segmented blade tip shrouds is deleteriously effected by the leakage of working medium gases across the tips of the rotor blades as the blades pass each gap between adjacent shroud segments. According to the present invention, an annular shroud which surrounds the tips of the turbine blades in a gas turbine engine comprises a plurality of arcuate segments each having a sealing surface and one or more chambers which extend circumferentially beneath the sealing surface and are adapted to receive and distribute cooling air about the surface, wherein a portion of the cooling air is flowable to the gap between adjacent shroud segments.
A primary feature of the present invention is the plurality of arcuate segments which comprise the blade tip shroud. Another feature of the invention is the cooling air chamber of each shroud segment which receives and distributes cooling air about the portion of each segment which is exposed to the hot working medium gases flowing thereacross. One or more passages communicatively join the chamber to the gap between adjacent segments. Lugs extend circumferentially from each segment to interlock with the lugs of the adjacent segment.
A principal advantage of the present invention is the improved performance attributable to the present construction which reduces the leakage of working medium gases across the tips of the rotor bldes. Air flowed to the gap between adjacent segments aerodynamically fills the gap to maintain continuity of the sealing surface between segments. Performance is further improved through a reduction in the leakage of medium gases axially through the gap which is inhibited by the interlocking lugs.
The foregoing, and other objects, features and advantages of the present invention will become more apparent in the light of the following detailed description of the preferred embodiment thereof as shown in the accompanying drawing.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a cross section view showing a shroud surrounding the tips of the blades in the turbine section of an engine;
FIG. 2 is a sectional view taken along the line 2--2 as shown in FIG. 1;
FIG. 3 is a sectional view taken along the line 3--3 as shown in FIG. 2; and
FIG. 4 is an enlarged view illustrating the sealing action of the air admitted to the gap between adjacent segments.
DESCRIPTION OF THE PREFERRED EMBODIMENT
A portion of a gas turbine engine having a turbine section 10 is shown in FIG. 1. The turbine section has an annular flow path 12 extending axially downstream from a combustion chamber 14. Disposed across the flow path is a nozzle guide vane 16 which is cantilevered from a turbine case 18 and is rotatable in the embodiment shown. A plurality of the vanes 16 is spaced circumferential within the flow path at the location shown. Each vane 16 directs a portion of the working medium gases into a turbine blade 20 which has a tip 22 and extends radially outward from an engine rotor 24. A multiplicity of the blades 20 are located at the same axial position shown. The blades are radially enclosed by a shroud 26 which has a sealing surface 28 opposing the tips of the blades and, in the embodiment shown, has two or more parallel chambers 30 separated by ribs 32 which extend circumferentially beneath the sealing surface. The sealing surface has a multiplicity of hemispherical indentations 34 which are communicatively joined to respective chambers by transpiration cooling holes 36. Disposed between the chambers and a cooling air supply cavity 38 is a baffle plate 40 having a plurality of impingement orifices 42. Conduit means which are not specifically shown supply air to the cavity 38.
As is shown in FIG. 2, the shroud 26 comprises a plurality of segments 44 having interlocking lugs 46 which extend from the abutting ends of each segment. Between each pair of adjacent segments is a circumferential gap 48. The gap includes a triangularly shaped slot 50 as shown in the FIG. 3 sectional view. Disposed within the slot 50 is a correspondingly shaped seal member 52. One or more lug passages 54 extend from the chambers to the gap region.
During operation of the engine pressurized air and fuel are burned in the combustor 14 and flow axially downstream in the flow path 12 through the turbine section of the engine. In the region adjacent the shroud 26, the pressure of the working medium gases in a typical engine at takeoff decreases from approximately 175 pounds per square inch to approximately 100 pounds per square inch. The maximum local temperature of the medium gases in the corresponding area remains approximately 3400 degrees Fahrenheit. The shrouds of the downstream stages are exposed to reduced temperatures and pressures but may also advantageously employ the concepts disclosed herein.
The combination of impingement cooling and transpiration cooling techniques, as employed in the present embodiment, prevents the wasteful allotment of cooling capacity to regions of lower temperature and pressure while maintaining the temperature of the material comprising the shroud at a level consonant with durable operation of the turbine. Cooling air from the compressor section of the engine, which is sufficiently high in pressure to cause the air to flow into the local area of the turbine without auxiliary pumping and is sufficiently low in temperature to provide the required cooling capacity, is first flowable to the air supply cavity 38 through conduit means which are not specifically shown. The conduit means are either external to the turbine case 18 or contained therein. Air from the cavity 38 is directed by the orifices 42 in the baffle plate 40 into the parallel chambers 30 and against the opposing wall of the chamber. In most preferred constructions, a pressure ratio across the baffle plate within the range of 1.1 to 1.85 is sufficient to cause the air passing thereacross to impinge upon the opposing wall. The impinging flow establishes a heat transfer rate between the shroud material and the cooling medium which is substantially greater than that obtainable with conventional convective cooling.
The cooling air is further flowable from the chambers 30 to the sealing surface 28 of the shroud 26 through the transpiration cooling holes 36. A pressure ratio across the shroud in most preferred constructions of approximately 1.25 produces exit velocities from the holes 36 which are sufficiently low to permit the air flowing therethrough to adhere to the sealing surface 28. The low air velocities prevent over penetration of the working medium gases by the cooling air which would interrupt both the flow of cooling air and the flow of medium gases and render the cooling technique ineffective. The holes 36 may be perpendicular to the sealing surface 28 or may be slanted in the direction of flow thereacross to increase the likelihood that the cooling air will adhere to the sealing surface. Hemispherical indentations 34 in the sealing surface intersect the holes 36 and further reduce the velocity of the exuding flow while preventing closure of the holes in the event that the shroud is struck by the passing blade tips during operation of the engine.
The circumferential gap 48 between each pair of adjacent shroud segments is sized to accommodate the maximum differential thermal expansion between the shroud 26 and the supporting turbine case 18 and, in a typical engine, is on the order of 0.045 inch. The interlocking lugs 46, which extend circumferentially from each shroud segment, block the axial flow of working medium gases through the gap 48 as is shown in FIGS. 2 and 3. As is illustrated in FIG. 4, the lug passages 54 supply air to the gap region to aerodynamically fill the gap and maintain continuity of the sealing surface between adjacent segments. The leakage of working medium gases across the tip from the pressure side (A) of the airfoil to the suction side (B) is reduced as the adverse effect of the gap 48 is minimized. The air supplied by the lug passages 54 additionally cools the gap region by preventing the ingestion of hot medium gases into the gap.
The radial leakage of excessive cooling air across the gap 48 from the supply cavity 38 to the flow path 12 is prevented by the seal member 52 which is disposed within the triangularly shaped slot 50. The differential pressure between the cavity 38 and the flow path 12 urges the seal member against the radially inward apex of the slot. Regardless of the size of the gap 48 as established by the engine thermal condition, the slot 50 retains its triangular shape and the seal 52 remains functionally effective at the apex.
The shroud 26 has been shown and described with respect to the blade tips 22 in the turbine section of the engine; however, the aerodynamic concepts taught are equally applicable to shrouds surrounding the blade tips in the compressor section of the engine and are equally applicable to the shroud surrounding the tips of cantilevered vanes as shown in FIG. 1. Furthermore, one skilled in the art will recognize that the aerodynamic concepts may also be applied to a segmented seal land such as that surrounding a knife edge labyrinth seal. Other various changes and omissions in the form and detail of the preferred embodiments described may be made without departing from the spirit and the scope of the invention.
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A coolable shroud having a sealing surface surrounding the tips of the turbine blades of a gas turbine engine is disclosed. The shroud comprises a plurality of arcuate segments which are supported by the turbine case in end to end relationship concentrically about the axis of the engine. Each segment is adapted to receive and distribute cooling air about the walls of the shroud which are exposed to the hot working medium gases flowing through the turbine during operation of the engine. Cooling air is flowable to the gap between adjacent shroud segments to maintain continuity of the sealing surface across the gap.
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[0001] This application is related to and claims priority to U.S. Provisional Application No. 61/911,605, by Brian K. Noel, entitled “Articulating Aiming Support,” filed on Dec. 4, 2013.
FIELD OF USE
[0002] The present invention relates to a articulating aiming support for use with a firearm or photographic equipment.
BACKGROUND OF THE INVENTION
[0003] Prior approaches to articulating aiming supports for firearms and photographic equipment involve a rest which is placed upon a flat surface, such as a shooting bench, or on the ground and then leveled with adjustable feet so as to insure a flat and stable shooting platform for the marksman.
[0004] Tree stand mounted rests work via the same principle, while being attached to the tree stand in some way, and include a pivot enabling the marksman to move within a certain range while maintaining a steady shooting position.
[0005] Some of the prior art includes:
U.S. Pat. No. 6,637,708 (Peterson) discloses an aiming support apparatus dependable from a central portion of a shooting platform is provided. The apparatus includes an arm having a base and an extension selectively extendible from a free end of the arm base. The arm extension includes a socket adapted to receive a shooting staff. The arm base is suspended from a bracket assembly for pivot motion about a pivot axis. The bracket assembly is affixable to the shooting platform so as to substantially underlay a shooter positioned thereon, the socket being swingingly positionable beyond a perimeter of the shooting platform in response to a marksman's torso motions in furtherance of pursuit of a scoped target. U.S. Pat. No. 8,393,106 (Cauley; et al.) discloses shooting rests having elevation adjustment assemblies are disclosed herein. One embodiment of the disclosure, for example, is directed to a shooting rest for supporting a firearm having a buttstock spaced apart from a forestock. The shooting rest includes a first base portion carrying a first support for supporting the buttstock and a second base portion coupled to the first base portion and carrying a second support for supporting the forestock. U.S. Pat. No. 8,356,442 (Potterfield; et. al.) discloses adjustable shooting rests and shooting rest assemblies are disclosed herein. In one embodiment, a shooting rest includes a rest assembly for supporting a forestock of a firearm. The rest assembly includes a base member and first and second upright members extending from the base member. A position of each of the first and second upright members is independently adjustable with reference to the base member. The shooting rest also includes a support assembly coupled to the rest assembly to move the rest assembly in a first direction and in a second direction. U.S. Pat. No. 5,979,099 (Kervin) discloses a truck mountable shooting rest that includes an attachment structure that is attachable to the bed wall of a pickup truck and a rifle support structure that is adjustably positionable by the user with respect to the attachment structure. The attachment structure includes a deformable friction insert sized to deformably friction fit into a bedwall hole of a pickup truck bedwall, a stop block formed at an end of the friction insert, and a support rod passageway formed through the friction insert and the stop block.
[0010] What is needed is a portable, lightweight, easy to use articulated aiming support which is attachable to a tree stand or other elevated platform, giving the user the ability to acquire targets from a variety of locations, while enabling the user to maintain steady aim, increasing the likelihood of hitting the desired target or of capturing high quality photographic images.
SUMMARY OF THE INVENTION
[0011] The primary object of the articulating aiming support of the present invention is to give the marksman or a photographer a steady, portable, and easily adjustable platform from which to aim from an elevated position.
[0012] The articulating aiming support of the present invention addresses these needs and objectives.
[0013] The articulating aiming support stabilizes a firearm relative to a tree stand. The articulating aiming support comprises a pivot, a plurality of support arms, a main support tube, an extension tube, an extension tube lock, and a shooting stick holder. The pivot is positionable underneath a tree stand, the tree stand is mountable in a tree, and the tree stand is capable of supporting the weight of a marksman. The plurality of support arms are attachable to the pivot, each support arm including a support pad for mounting the tree stand. The main support tube is swingably attachable to the pivot. The extension tube is slideably engageable relative to the main support tube. The extension tube lock secures the position of the extension tube relative to the main support tube. The shooting stick holder securely retains a shooting stick, the shooting stick stabilizes a firearm, the shooting stick holder is secured to the extension tube. The shooting stick holder, in use, enables the marksman to track a target as the target moves below and about the tree stand. The articulating aiming support collapses down for ease of transport and storage and may be made from any, strong lightweight material.
[0014] In the first preferred embodiment of the present invention, the shooting rest system includes two sections of tubing, which collapse into one another, which have a pivot attached for mounting to a tree stand. Attached to the piece of tubing which extends from the tube attached to the pivot is a rest with three arms which swing outwardly and lock into place. Attached to said arms are adjustable pads which enable the marksman to attach the apparatus to the bottom of a tree stand, thus stabilizing the rifle and enabling for a more accurate and stable shot. The rest will attach to the underside of a tree stand and enable essentially full angular rotation (about 350 degrees) providing the marksman with the ability to shoot from any essentially angle. The articulating aiming support of the present invention is collapsible enabling for a small form factor and is easily stowed into a backpack or carried by hand.
[0015] The articulating aiming support of the present invention can also be used with photographic equipment to take high quality photographic images from an elevated stand.
[0016] For a complete understanding of the articulating aiming support apparatus of the present invention, reference is made to the following summary of the invention detailed description and accompanying drawings in which the presently preferred embodiments of the invention are shown by way of example. As the invention may be embodied in many forms without departing from spirit of essential characteristics thereof, it is expressly understood that the drawings are for purposes of illustration and description only, and are not intended as a definition of the limits of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 depicts an environmental view of the preferred embodiment of the articulating aiming support of the present invention with a shooting stick affixed to an elevated stand or tree stand.
[0018] FIG. 2 depicts a perspective view of a first preferred embodiment of the articulating aiming support shown in FIG. 1 .
[0019] FIGS. 3 , 4 , and 5 depict the front view, the side view, and the top view, respectively, of the articulating aiming support of FIG. 2 .
[0020] FIG. 6 depicts an environmental view of a second preferred embodiment of the articulating aiming support of the present invention with a camera mount affixed to an elevated stand.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0021] Referring now to the drawings, FIG. 1 depicts a perspective view of the preferred embodiment of the articulated aiming support [ 10 ] of the present invention with a tree stand [ 38 ] with a shooting stick [ 24 ] inserted into a stabilization mount [ 35 ] and FIG. 2 depicts a perspective view of the first preferred embodiment of the articulated aiming support [ 10 ] shown in FIG. 1 .
[0022] The articulated aiming support [ 10 ] of the present invention comprises a stabilization mount which is attached to the main tube [ 12 ] with the extension tube [ 18 ] shown in the extended position. The extension tube [ 18 ] is of a smaller diameter than the main tube [ 12 ] enabling the extension tube [ 18 ] to slide into the main tube [ 12 ]. Attached to the main tube is a tube lock [ 20 ] which locks the extension tube [ 18 ] preventing it from sliding back into the main tube [ 12 ] during use. The tube lock [ 20 ] could also be a ball detent type lock, which will automatically lock into a recess in the extension tube [ 18 ] when it is extended. To retract the extension tube[ 18 ] back into the main tube [ 12 ] the user will need to depress the ball, and while holding it down, slide the tube until the ball is no longer in the recess in the extension tube
[0023] . Once the extension tube is slid completely back into the main tube [ 12 ] the ball detent will lock into a recess at the end of the extension tube [ 18 ], preventing the extension tube [ 18 ] from extending during transport, or in the case a shorter rest is needed. Along the base of the extension tube [ 18 ] are equally spaced recesses, which will enable the length of the rest to be adjusted depending on user preference. The extension tube [ 12 ] is attached to the shooting stick holder [ 14 ], enabling free rotational movement in which it is estimated to be about a range of 350 ° of the shooting stick relative to the tree stand.
[0024] Attached to the end of the extension tube [ 18 ] are three support arms [ 30 ], which are perforated for weight reduction and are mounted in such a manner so as to enable them to be folded beneath one another so as to enable for ease of storage and transport. Conversely, the mounting point of the support arms [ 30 ] enables for the support arms [ 30 ] to be detached for replacement, or for transport. At the ends of the support arms [ 30 ] are mounting pads [ 25 ] which enable the user to attach to the rest to the bottom of a tree stand. The mounting pads [ 25 ] are threaded on the bottom and are attached via a wing nut [ 32 ]. The mounting pads [ 25 ] can be mounted to the support arm [ 30 ] in any of the weight reduction holes which are drilled into the support arm [ 30 ]. The mounting pads [ 25 ] are adjustable for height and each can be set differently if the marksman desires so as to enable for different shooting heights, to take into account obstructions in the marksman's line of sight.
[0025] The shooting stick holder [ 14 ] enables the marksman to rotate the shooting stick [ 24 ] about 350° degrees relative to the tree stand [ 22 ], enabling for a panoramic shooting view. The pivot [ 15 ] mounts to the underside of a tree stand and moves freely, thereby enabling the marksman to move the articulating aiming support [ 10 ] out of the way when not needed and to quickly use it when necessary.
[0026] The apparatus comprises a stabilization mount [ 35 ], which is attached to the main tube [ 12 ] with the extension tube [ 18 ] shown in the extended position. The extension tube [ 18 ] is of a smaller diameter than the main tube [ 12 ] enabling the extension tube
[0027] to slide into the main tube [ 12 ]. Attached to the main tube is a tube lock [ 20 ] which locks the extension tube [ 18 ] preventing it from sliding relative to the main tube [ 12 ] during use. The tube lock [ 20 ] can also be a ball detent type lock, which will automatically lock into a recess in the extension tube [ 18 ] when it is extended. To retract the extension tube[ 18 ] back into the main tube [ 12 ] the user will need to depress the ball, and while holding it down, slide the tube until the ball is no longer in the recess in the extension tube [ 18 ]. Once the extension tube is slid completely back into the main tube [ 12 ] the ball detent will lock into a recess at the end of the extension tube [ 18 ], preventing the extension tube [ 18 ] from extending during transport, or in the case a shorter rest is needed. Along the base of the extension tube [ 18 ] are equally spaced recesses, which will enable the length of the rest to be adjusted depending on user preference. The extension tube [ 12 ] is attached to the pivot [ 15 ], enabling free movement in a 350 degree range.
[0028] A stabilization apparatus for a rifle, such as a shooting stick [ 24 ], or camera mount [ 38 ], is inserted into the stabilization mount [ 35 ], enabling the user to stabilize their rifle, or camera for accurate and stable shots. For a rifle, the accuracy and control gained from resting the firearm onto a stable platform is immeasurable, while for a photographer, the stability gain guarantees a picture which is free from blur. Conversely, a video camera mount can be substituted for videographers who are making nature films, or if they are using a stand mounted to a pole.
[0029] Attached to the end of the extension tube [ 18 ] are three support arms [ 30 ], which are perforated for weight reduction and are mounted in such a manner so as to enable them to be folded beneath one another so as to enable for ease of storage and transport. Conversely, the mounting point of the support arms [ 30 ] enables for the support arms [ 30 ] to be detached for replacement, or for transport. At the ends of the support arms [ 30 ] are mounting pads [ 25 ] which enable the user to attach to the rest to the bottom of a tree stand. The mounting pads [ 25 ] are threaded on the bottom and are attached via a wing nut [ 32 ]. The mounting pads [ 25 ] can be mounted to the support arm [ 30 ] in any of the weight reduction holes drilled into the support arm [ 30 ]. The mounting pads [ 25 ] are adjustable for height and each can be set to a different if the user desires so as to enable for different shooting heights, to take into account obstructions in the marksman's line of sight.
[0030] The pivot [ 15 ] enables the marksman to rotate the firearms mount [ 10 ] 350 degrees, enabling for a panoramic shooting view. The pivot [ 15 ] mounts to the underside of a tree stand and moves freely, thus enabling the marksman to move the firearms rest [ 10 ] out of the way when not needed and to quickly utilized it when necessary.
[0031] FIGS. 3 , 4 , and 5 depict the front view, the side view, and the top view, respectively, of the articulating aiming support [ 10 ] of FIG. 2 .
[0032] In FIG. 5 , it is clearly visible how the extension tube [ 18 ] slides into the main tube [ 12 ] with the tube lock [ 20 ] securely engaging the extension tube [ 18 ] preventing it from sliding completely out of the main tube [ 12 ] and providing a stable shooting platform.
[0033] The articulated aiming support [ 10 ] main tube [ 12 ] can be made from aluminum, steel, polycarbonate, or any other material utilizing square, round, oval, hexagonal tubing etc.
[0034] When the articulated aiming support [ 10 ] is completely collapsed and the support arms [ 30 ] folded inwardly over one another, it can be easily carried, stowed in a back pack, put underneath, or behind a vehicle seat.
[0035] FIG. 6 depicts an environmental view of a second preferred embodiment of the articulating aiming support of the present invention with a camera mount [ 39 ] affixed to an elevated stand. This embodiment is for photographers who want to photograph images from above. In this embodiment, a monopod mount can be inserted into the stabilization mount [ 35 ] enabling a stable platform from which a photographer can take pictures.
[0036] A stabilization apparatus for a firearm is inserted into the shooting stick holder [ 14 ], enabling the user to stabilize their firearm, or camera for accurate and stable shots. For a firearm, the accuracy and control gained from resting the firearm onto a stable platform is immeasurable, while for a photographer, the stability gain, guarantees a picture which is free from blur. Conversely, a video camera mount is substituted for videographers who are making nature films, or if they are using a stand mounted to a pole.
[0037] Throughout this application, various Patents and Applications are referenced by number and inventor. The disclosures of these documents in their entireties are hereby incorporated by reference into this specification in order to more fully describe the state of the art to which this invention pertains.
[0038] It is evident that many alternatives, modifications, and variations of the articulated aiming support [ 10 ] of the present invention will be apparent to those skilled in the art in light of the disclosure herein. It is intended that the metes and bounds of the present invention be determined by the appended claims rather than by the language of the above specification, and that all such alternatives, modifications, and variations which form a conjointly cooperative equivalent are intended to be included within the spirit and scope of these claims.
PARTS LIST
[0000]
10 . Articulating Aiming Support
12 . Main Tube
14 . Shooting Stick Holder
15 . Pivoting Member
18 . Extension Tube
20 . Extension Tube Lock
22 . Tree Stand
24 . Shooting Stick
25 . Firearm Support Pad
30 . Support Arm
32 . Wing Nut
35 . Rifle Stabilization Mount
34 . Double Locknuts
36 . Nylon Washer
38 . Positioning Nut
39 . Camera Mount
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An articulating aiming support for use in an elevated stand enables a marksman to stabilize shots for increased accuracy while reducing fatigue from holding a rifle in a free position. The rest may also be used for photographic uses by using a camera mount in place of a shooting stick. The firearms rest comprises of two sections of tubing which slide into one another with a pivot mounted to one end, which is used to mount the rest onto a tree stand, while the tube which extends has a plurality of supports on the other end. These supports have mounting pads located on the ends, which are adjustable for height, which the marksman uses mount the apparatus to base of a tree stand, steadying their shots. The firearms rest collapses down for ease of transport and storage and may be made from any, strong lightweight material.
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FIELD OF THE INVENTION
The present invention relates to an improved fiberglass casting tape. The casting tapes of the present invention have little tendency to fray or ravel and have substantial extensibility in their length direction which results in improved conformability, and thus allows better application of the casting tapes to the patient. The improved conformability results in a cast which better fits or conforms to the patient's limb.
BACKGROUND OF THE INVENTION
Plaster of Paris casts have been in use to immobilize body members or limbs for some time. In recent years, the plaster of Paris bandages have been supplemented and, to some extent, superseded by synthetic casting tapes or bandages which employ polymeric materials on a substrate. The polymeric materials are of the type that have been cured by exposure to ultra violet light or which would cure when reacted with water. Examples of the ultra violet light cured cast can be found in U.S. Pat. No. 3,881,473. More recently, water-cured or water-reactive polyurethane compositions have been used in forming orthopedic casts and the polyurethane compositions have largely supplanted other polymeric synthetic casting materials. The polyurethane casting materials are of the type which are disclosed in U.S. Pat. Nos. 4,376,438 and 4,411,262.
The fibrous substrate used in the synthetic casting tapes may be made from any natural or synthetic fiber including a fiberglass material. The fiberglass materials offer advantages in terms of strength of the finished cast when compared to other fibers and various constructions of fiberglass fabrics have been used for the substrates for synthetic casting tapes. The patents mentioned above disclose the use of different fiberglass materials as the substrate for casting tapes. In addition, U.S. Pat. Nos. 3,686,725, 3,787,272 and 3,882,857 disclose specific fiberglass materials, or the treatment of fiberglass materials, to produce fiberglass substrates which are particularly suitable for use in orthopedic casts.
U.S. Pat. No. 4,323,061 discloses a cast substrate made from a combination of glass fibers and a second fiber such as cotton, flax, rayon, wool, acrylic resin, nylon, polytetrafluoroethylene or polyester. The purpose of the second fiber in the substrate is to hold the curable resin on the substrate.
U.S. Pat. No. 3,332,416 discloses a plaster of Paris cast bandage with a woven substrate made with a combination of elastic and inelastic fibers.
U.S. Pat. No. 4,609,578 discloses a fiberglass substrate for casting tapes which has an extensibility of at least 20% and up to 25% to 35%. The fiberglass substrate is heat-set to prevent fraying. Care must be taken when handling of the fabric after knitting and before and after heat treatment to avoid applying undue tension to the fabric which would distort the knots and loops, i.e. stretch the fabric, and permanently lose some of the stretch of the fabric.
U.S. Pat. No. 4,668,563 discloses a cast substrate made from a combination of glass fibers and an elastomeric highly extensible fiber. The substrate has a stretch of from 40 to 200%. The elastomeric fiber is selected or is treated to insure that it is compatible with the water curable polyurethane prepolymer employed in the casting tape. Although the conformability of the tape disclosed is excellent, the presence of the elastomeric fiber in the substrate can cause storage stability or shelf life problems or add cost to the product because of the treatment of the elastomeric fiber that is required to insure longer shelf life. The presence of the elastomeric fiber in the finished product also necessitates a secondary process step, i.e. coating the fabric with a binder, to reduce fraying or ravel.
SUMMARY OF THE PRESENT INVENTION
The present invention provides an orthopedic casting tape which has a substrate which is all fiberglass does not fray or ravel but which has a very high degree of extensibility. The casting tape of the present invention is knitted with an elastic fiber in the length direction of the fabric which acts to compact or gather the fabric in the length direction when the fabric is removed from the knitting machine. The elastic fiber is subsequently removed from the fabric by a heat treatment process which removes the elastic yarn and heat sets the fabric in a contracted configuration with little or no fraying or raveling. The removal of the elastic fiber avoids the problems of storage stability which may be caused by the presence of the elastomeric fiber in the finished casting tape.
The presence of the elastic fiber in the knitted fabric allows the fabric to be handled normally, i.e. without undue regard to tension, until the elastic fiber is removed from the fabric. After the elastic fiber is removed from the fabric, some care should be taken to avoid applying tension to the fabric. However since the fabric is heat set by the process which eliminates the elastic yarn and therefore has some memory, normal handling during processing will not cause a major loss of stretch. Also, since the elastic fiber is removed from the fabric, the concerns of the reactivity of the water curable resin with the elastic fiber and the resultant storage stability or shelf life problems are not present in casting tapes made from the fabric of the present invention.
The purpose of the use of the elastic fiber is to compact or gather the fabric when the fabric is removed from the knitting machine. When the fabric is knitted the elastic yarn is stretched by being fed under predetermined tension to the knitting machine. The degree of tension or stretch of the elastic fiber or yarn will depend on the percent stretch desired in the final fabric. Increasing the tension in the elastic fiber results in more stretch in the fabric. When the knitted fabric is removed from the knitting needles on the machine, the stretched elastic fibers exert a force on the fabric which pulls the fabric in the length direction. The elastic fibers pull the courses of the fabric into closer proximity to each other thereby causing the fabric to contract. For example, a fabric of the present invention may be knitted with about 12 courses per inch and when the fabric is removed from the knitting machine and gathered by the elastic yarn the fabric may have 20 courses per inch. The fabric retains its compacted or gathered states to a substantial degree even after the elastic fibers are removed from the fabric by the heat treatment process because the fiberglass yarns are heat set in the contracted state which imparts a "spring like" memory to them.
The compacted or gathered fabric has a greater extensibility than a similar fabric made not using an elastic fiber.
BRIEF DESCRIPTION OF THE DRAWING
FIGS. 1 and 2 are three bar Raschel knits in which bar 1 performs a simple chain stitch and bars 2 and 3 perform lapping motions to lay in yarn.
FIG. 3 is a four bar Raschel knit in which bar 1 performs a simple chain stitch and bars 2, 3 and 4 perform lapping motions to lay in yarn.
FIG. 4 is a block diagram of the steps of the process of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
The substrate of the casting tape of the present invention is knitted with a combination of continuous filament fiberglass and elastic filaments or yarns. Fiberglass substrates are generally characterized as made from filaments which are formed into yarn, sized and knitted into a desired construction. In the present invention the substrates are knitted on a Raschel Knitting Machine having 6 to 28 needles per inch. The cast substrate fabrics of the present invention are knitted fabrics which combine high modulus fiberglass with an elastomeric highly extensible fiber when the fabric is knitted. The elastomeric extensible fiber may be a natural rubber or a synthetic elastomer such as polyisoprene, polybutadiene, copolymers of a diene and styrene, copolymers of acrylonitrile and a diene or polychloroprene, copolymers of chloroprene and other monomers, ethylene propylene elastomers including ethylene propylene copolymers and ethylene propylene diene terpolymers, and thermoplastic elastomers which are block copolymers of styrene and butadiene or isoprene. The elastomeric extensible fiber may also be a spandex (polyurethane) fiber. The most common commercially available elastic yarns are natural rubber and spandex. Natural rubber has been used as the elastic yarn in the process of forming the substrate of the present invention.
The extensible fiber is present in the knit fabric in the warp or wale fibers, i.e., machine direction, but not in the fill fibers. The elastic or extensible fiber cannot be the fiber used to form the loop or chain stitch as the elastic fiber will eventually be removed from the fabric. Preferably about 0.25 to 25% of the fibers based on the total volume of fibers in the fabric are extensible. The knitted fabric, prior to the removal of the elastic fiber, should have a stretch in the length direction of at least 70% and up to 200%. The process of removing the extensible fiber by a heat treatment process could reduce the stretchability by some amount, 50% or more, of the stretch of the fabric prior to heating. Therefore, the preferred extensibility of the fabric, before heating to remove the elastic extensible fiber, is between 70% and 200%.
Since the elastic fiber used in the present invention will be removed from the substrate before the substrate is coated with the polyurethane prepolymer, i.e. a water curable isocyanate terminated resin, there is no concern of the possible reaction between the elastic fiber and the polyurethane prepolymer.
The knit patterns that may be used in the manufacture of the substrates of the present invention are numerous. Generally, the fabrics are knitted using a three bar knitting machine, one bar for the elastic thread and two bars for the fiberglass. In the knitted substrates of the present invention the elastic yarn must give the fabric stretch in the length direction of the fabric. The elastic yarn may be in bar 3, of a 3-bar or possibly bar 4 of a 4 bar Raschel knit construction fabric. As previously indicated the elastic yarn in the present invention should not be in the chain stitch. The elastic yarn may be intermittently spaced in the fabric. There need not be an elastic fiber for every needle employed in knitting the fabric. The elastic fiber need only be present in the fabric in a sufficient amount to give the desired compaction to the fabric when the fabric is removed from the knitting machine.
The third bar, and the fourth bar if used, could be used to lay in fiberglass in a zig-zag or a sinusoidal pattern which would increase the crush strength of the final cast by comparison to transversely laid in yarns in these positions. The elastic yarn may be in bar 3 in 3-bar knit or in bars 3 and/or 4 in a 4-bar knit fabric. The tension in the elastic yarn during the knitting process is important. The tension in the elastic yarn should be controlled to cause the fabric to gather or bunch uniformly to the desired degree when it is released from the knitting machine. When the finished heat treated fabric is stretched, the extensibility is achieved as the gathers are pulled out and any further stretch or extensibility of the fabric is limited by the loops in the chain stitch. The preferred fabric is a 3 bar knit with the elastic yarn in bar 3.
Typical bar patterns for the knit fabric substrates of the present invention are shown in the drawings.
FIG. 1 is a three bar pattern with the elastic thread on bar 3 and fiberglass on bars 1 and 2.
FIG. 2 is a three bar pattern in which the elastic thread is on bar 3 and fiberglass is on bars 1 and 2. This fabric would be heavier than the fabric of FIG. 1 as more fiberglass would be added to the fabric by bar 2.
FIG. 3 is a four bar pattern in which the elastic thread is on bar 3 or 4.
It should be understood that the above bar patterns may be modified. For example, the pattern of FIG. 3 may be employed with an elastic thread in bars 3 and 4 and fiberglass yarn in bars 1 and 2.
Also, the patterns of FIGS. 1 and 2 could be modified by employing a zig-zag pattern on bar 3 similar to that shown in bar 3 or bar 4 of FIG. 3. The particular knit pattern is not important as long as the fabric is compacted by the tension of the elastic yarn when the fabric is removed from the knitting machine.
The elastic fiber is removed from the fabric by heating the fabric in an oven at a temperature sufficiently high to burn off the elastic yarn and set the fabric in the contracted state. This can be accomplished by heating the fabric in an oven at a temperature between 400° F. and about 850° F. Heating the fabric to temperatures above about 1000° F. should be avoided as subjecting the fiberglass to temperatures of about 1000° F. can weaken the fiberglass yarns in the fabric which may result in reduced strength of casts made from such fabrics. Rapid burning of the elastic yarn should be avoided as this can increase the temperature of the fiberglass high enough to cause breakage of the fiberglass yarns.
The burning conditions can be varied depending on the particular elastomeric fiber used but the heat treatment must be sufficient to set the fiberglass yarns in the contracted configuration.
After the fabric is treated to remove the elastic yarn, the fabric should be carefully handled so that it is not stretched sufficiently to pull the gathers completely out of the fabric during the winding, coating and other casting tape manufacturing procedures.
EXAMPLE I
A fabric was knitted on a 24-gauge Raschel knitting machine using a 3-bar configuration as shown in FIG. 1. The first bar contained DE75 1/0 fiberglass yarn, the second bar contained the same fiberglass, and the third bar contained a natural rubber thread designated L83 from J. P. Stevens. The rubber thread was fed to the knitting machine under sufficient tension so that when the fabric was removed from the knitting machine and was allowed to contract by the action of the elastic yarn, the fabric had a machine direction stretch of 75%. The contracted fabric was then formed into a loose skein and placed in an oven at a room temperature. The temperature of the oven was raised to 450° F. during a period of two hours and held at 450° F. for 90 minutes. The temperature of the oven was then raised to 600° F. over a period of one hour and held at that temperature for one hour. The oven was then heated to a temperature of 695° F. over a period of one hour and held at that temperature for six hours. The oven was then allowed to cool to room temperature and the fabric removed for subsequent use as a substrate for a water reactive polyurethane casting tape. When the elastic fiber had been removed from the fabric samples the fabric had an elongation of about 35% (between 32% and 37%). The fabric was coated at 42% add on, with a water reactive with a polyurethane prepolymer of the type disclosed in U.S. Pat. No. 4,433,680 the disclosure of which is incorporated herein by reference and used in commercially available polyurethane casting tapes. The resulting casting tape was evaluated and was found to have improved conformability when compared to casting tapes made with heat set fiberglass coated with the same resin.
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A method of making a non raveling stretchable fiberglass fabric by knitting an elastic yarn under tension into the fabric in the length direction, releasing the tension from the elastic yarn to compact the fabric and removing the elastic yarn from the fabric.
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CROSS-REFERENCE TO RELATED APPLICATIONS
The present application claims priority under 35 USC §119 from Japanese Patent Publication No. 2001-363240, filed Nov. 28, 2001, the disclosure of which is incorporated herein by reference. The present application is a continuation of U.S. application No. Ser. No. 10/083,540 filed Feb. 27, 2002 now U.S. Pat. No. 6,828,964, which has been allowed, the disclosure of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates to a display method and display control device for displaying, in accordance with a visual field from a set viewpoint, data objects situated in a three-dimensional virtual space.
2. Description of Related Art
Computers connected to networks, such as the Internet for example, are capable of retrieving massive amounts of diverse information. In addition, as the capacity of storage media increases, even stand-alone information machines have become able to utilize vast amounts of diverse information.
In order to make use of such large amounts of diverse information, GUIs (graphical user interfaces) that employ a desktop metaphor, such as Microsoft Windows™ are being used, as are web browsers such as Microsoft Internet Explorer™ and Netscape Navigator™. These applications display viewing target informational content arranged on a screen in a static and planar manner; and in order to view the informational-content items in turn, succeeding subject matter must be displayed by replacing the subject matter being displayed in the active window, or must be displayed by changing the active attribute of windows being displayed on the screen in an overlapping manner.
When a plurality of informational items is displayed by switching from one display to another, the sense of continuity on the screen is lost, leading to the problem of a 25 user having trouble understanding how the individual contents are related to each other.
In order to solve such problems, an information display method has been proposed (Japanese Pat. App. No. 2001-162322 [filed May 30, 2001]; Laid-Open No. 2000-172248) wherein concatenatedly linked data objects are arranged in a three-dimensional virtual space, and based on a visual field defined in the virtual space, the data objects are displayed on a display screen; and wherein information can be perused by following along links while the display screen is changed uninterruptedly by changing the visual field smoothly.
A conventional technique of this sort will be explained using FIGS. 5 and 6 . FIG. 5 is a conceptual view of a link structure of concatenatedly linked data objects, and FIG. 6 10 is example displays of the concatenatedly linked data objects.
In FIG. 5 , data objects 102 and 103 are represented within data object 101 as links 112 and 113 , respectively, and data objects 104 and 105 are represented within data object 102 as links 114 and 115 , respectively. Data object 106 is represented within data object 104 as link 116 .
In display example 301 at (A) in FIG. 6 , data object 101 and data objects 102 and 103 linked to data object 101 are displayed.
When a shift-viewpoint instruction is accepted, the display range is changed according to the instruction, transitioning, for example, to the state shown in display example 302 at (B) in FIG. 6 . In this display example 302 , data object 101 , data object 102 linked to data object 101 , and data objects 104 and 105 linked to data object 102 are displayed.
When a further shift-viewpoint instruction is accepted, the state shown in display example 303 at (C) in FIG. 6 ensues. In this display example 303 , data object 102 , data object 104 linked to data object 102 , and data object 106 linked to data object 104 are displayed.
In display examples 301 through 304 , the data object that occupies the largest area within the display screen is displayed in detail, and the preceding/following relationships of the data objects are set in correspondence with the link modes and displayed. The fact that the display within the field of view always changes smoothly in response to the shift-viewpoint instructions enables a user to follow the links and view the data objects.
The information display method described above readily enables viewing by following concatenatedly linked information, and enables remedying the problem of losing sight of the interrelationships among the informational-content items. However, this method does not take into consideration such matters as: displaying supplemental information in connection with displayed data objects; displaying information in more detail in connection with displayed data objects; providing means for dialogue with a user in situations where required; or executing application programs linked to the display of information and associated with that information.
SUMMARY OF THE INVENTION
The present invention offers a configuration that enables viewing a plurality of data objects situated in a virtual space as the visual field defined in the virtual space is changed smoothly; and that at the same time enables: supplemental information in connection with displayed data objects to be displayed; information in connection with displayed data objects to be displayed in more detail; means for dialogue with a user to be provided in situations where required; and application programs linked to the display of information and associated with that information to be executed.
A first aspect of the present invention is a data-object display method for situating a plurality of data objects within a three-dimensional virtual space in which a visual field is defined and displaying, from a set virtual viewpoint, data objects located within the visual field. The data-object display method includes: a step of accepting virtual-viewpoint location changes; a step of continuously changing the visual field based on the virtual-viewpoint location changes, and uninterruptedly changing the display of a data object located within the visual field; a step of distinguishing whether a data object located within the visual field satisfies predetermined geometric conditions for the visual field; and a step of executing, in respect of a data object satisfying the predetermined geometric conditions, a process preset in the data object.
In a second aspect, the invention is the data-object display method according to the first aspect, wherein the process preset in the data object displays a display image different from a virtual-space display image located within the visual field.
A third aspect is the data-object display method according to the second aspect, wherein the a separate image is displayed situated in front of the data object located within the visual field in the virtual space.
In a fourth aspect, the invention is the data-object display method according to the second aspect, wherein a separate image is displayed within a window different from a window in which the data object located within the visual field in the virtual space is displayed.
A fifth aspect of the invention is the data-object display method according to the second aspect, wherein a separate image is displayed within a frame different from, in an identical window with, a frame in which the data object located within the visual field in the virtual space is displayed.
In a sixth aspect, the invention is according to the second aspect, wherein at least one from among a message, a modal dialogue, a modeless dialogue or information related to the data object is displayed.
A seventh aspect of the invention is the data-object display method according to 5 any of the foregoing aspects, wherein the process preset in the data object executes a preset application program.
An eighth aspect of the present invention is an information display device for situating a plurality of data objects within a three-dimensional virtual space in which a visual field is defined and displaying, from a set virtual viewpoint, data objects located within the visual field. The information display device in this aspect of the invention includes: visual-field-data updating means for accepting virtual-viewpoint location changes; object data processing means for continuously changing the visual field based on the virtual-viewpoint location changes, and uninterruptedly changing the display of a data object located within the visual field; process-execute-conditions judging means for distinguishing whether a data object located within the visual field satisfies predetermined geometric conditions for the visual field; and visual-field-shift-linked process-executing means for executing, in respect of a data object satisfying the predetermined geometric conditions, a process preset in the data object.
An ninth aspect of the present invention is an information display device for situating a plurality of data objects within a three-dimensional virtual space in which a visual field is defined and displaying on a display screen, from a set virtual viewpoint, data objects located within the visual field. The information display device herein includes: visual-field-data updating means for accepting virtual-viewpoint location changes; object data processing means for continuously changing the visual field based on the virtual-viewpoint location changes, and uninterruptedly changing the display of a data object located within the visual field; process-execute-conditions judging means for distinguishing whether or not there is a data object located in the display-screen center and occupying a proportion of the display screen that is a predetermined value or more; and visual-field-shift-linked process-executing means for executing a process preset in the data object, based on judgment results from said process-execute-conditions judging.
An tenth aspect of the present invention is an information display device for situating a plurality of data objects within a three-dimensional virtual space in which a visual field is defined and displaying, from a set virtual viewpoint, data objects located within the visual field. The information display device in the aspect of the present invention includes: visual-field-data updating means for accepting virtual-viewpoint location changes; object data processing means for continuously changing the visual field based on the virtual-viewpoint location changes, and uninterruptedly changing the display of a data object located within the visual field; and visual-field-shift-linked process-executing means for executing, if the distance of a data object located in the visual field from the virtual viewpoint becomes a predetermined value, a process preset in the data object.
From the following detailed description in conjunction with the accompanying drawings, the foregoing and other objects, features, aspects and advantages of the present invention will become readily apparent to those skilled in the art.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a functional block diagram illustrating the configuration of one embodiment of the present invention;
FIG. 2 is a functional block diagram illustrating a portion of FIG. 1 in greater detail;
FIG. 3 is a control flowchart;
FIG. 4 is an explanatory diagram illustrating the geometric relationship between a visual field and a data object in a three-dimensional virtual space;
FIG. 5 is an explanatory diagram illustrating one example of the link structure of a group of data objects;
FIG. 6 is explanatory diagrams illustrating the link structure of a group of data objects, according to conventional technology;
FIG. 7 is an explanatory diagram illustrating a link structure, as set out in the present invention, for data objects to be displayed;
FIG. 8 is explanatory diagrams illustrating examples of message display linked to visual-field shift;
FIG. 9 is explanatory diagrams illustrating examples of modal-dialogue display linked to visual-field shift;
FIG. 10 is explanatory diagrams illustrating examples of related-information display linked to visual-field shift;
FIG. 11 is explanatory diagrams illustrating examples of display, linked to visual-field shift, of related information into a separate window;
FIG. 12 is explanatory diagrams illustrating examples of display, linked to visual-field shift, of related information into a separate frame;
FIG. 13 is explanatory diagrams illustrating examples of modeless-dialogue display linked to visual-field shift; and
FIG. 14 is explanatory diagrams illustrating examples of application-execution display linked to visual-field shift.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 is a control block diagram of an information-processing device employing a first embodiment of the present invention.
An information processing device 500 , which can be a personal computer, workstation or other type of computer, includes an input device 501 , which may be a keyboard, mouse or the like; an information storage device 502 , which may be a hard disk, CD-ROM or other information recording device; a network interface 503 , which is capable of connecting to the Internet, a LAN or the like; a program-storage unit 504 , which may be a ROM, hard disk or the like; a cache data storage unit 505 , comprising RAM or other memory; a display device 507 , which may be a cathode ray tube, liquid crystal display or the like; a frame memory 506 , which stores image data for images displayed on the display device 507 ; and a data processing unit 510 , which generates image data to be displayed on the display device 507 .
The data processing unit 510 comprises a CPU and memory, and includes: a process-control module 512 , a visual-field-data updating module 511 , an object-data processing module 514 , visual-field-shift-linked process-executing module 517 , and a display-image synthesizing module 519 , among other modules. The configuration may be made to have object-data processing modules 514 and visual-field-shift-linked process-executing modules 517 of a number of different kinds, to correspond to types of data objects or types of visual-field-shiftlinked processes; generally, these are realized in a form in which programs stored in the program-storage unit 504 are loaded onto memory and deployed.
Of the elements of the data processing unit 510 , the process-control module 512 controls overall processing.
The visual-field-data updating module 511 accepts instructions relating to visual field movement inputted from the input device 501 , moves a virtual viewpoint, and continuously shifts visual field data 513 within a virtual space seen from the virtual viewpoint. The display-image synthesizing module 519 synthesizes the partial display images generated by the object-data processing module 514 and visual-field-shift-linked process-executing module 517 , respectively, and generates an appropriate display image to be “displayed on the display device 507 .
Object data is stored in a data storage unit 530 . Object data is information acquired via the network interface 503 or information stored in the information storage device 502 , and is present as a plurality of items corresponding to data objects that are candidates for being placed in the virtual space and displayed.
As shown in FIG. 2 , object data 531 stored in the data storage unit 530 includes: object placement data 532 , which defines information relating to placement of a data object in a virtual space; object display content data 533 , which defines display content for a data object; and visual-field-shift-linked process content-defining data 534 , which defines the content of a process that is executed in conjunction with shifting the visual field, and, for executing that process, conditions that pertain to the geometric relation between the visual field and the target object.
The object-data processing module 514 carries out processes relating to a specified type of data object, and includes an object display image generation function unit 515 and a visual-field-shift-linked processing module 516 .
In the object-data processing module 514 , the object display image generation function unit 515 generates a data object display image based on the current visual field data 513 for a virtual space in which a plurality of data objects are placed. The object display image generation function unit 515 , each time a new display image frame is generated, generates a display image for a data object that is to be displayed, based on the visual field data 513 , object placement data 532 , and object display content data 533 , and writes this display image to the frame memory 506 via the display-image synthesizing module 519 .
The visual-field-shift-linked processing module 516 refers to the visual field data 513 , object placement data 532 , and visual-field-shift-linked process content-defining data 534 to control execution of pre-set processes in conjunction with shifting the visual field. This visual-fieldshift-linked processing module 516 includes a process-execute-conditions judging module 521 , which based on the visual field data 513 , object placement data 532 , and visual-field-shiftlinked process content-defining data 534 , judges from the geometric relation between visual field and data object whether conditions have been met for executing preset processes in conjunction with visual field movement. The visual-field-shift-linked processing module 516 controls the processes of the visual-field-shift-linked process-executing module 517 based on the determination results of the process-execute-conditions judging module 521 .
The visual-field-shift-linked process-executing module 517 , in conformance with control functions of the visual-field-shift-linked processing module 516 , executes processes designated in the visual-field-shift-linked process content-defining data 534 . The visual-field-shift-linked process-executing module 517 includes a visual-field-shift-linked information displaying module 518 ; and of the processes designated in the visual-field-shift-linked process content-defining data 534 , this visual-field-shift-linked information displaying module 518 generates display content for the display device 507 , which it writes to the frame memory 506 via the display-image synthesizing module 519 .
The configuration as described above enables the display of data objects while smoothly changing the display range by continuously shifting the visual field, in a virtual space in which a plurality of data objects are situated, and enables the execution of information display and like processes when predetermined geometric conditions between the visual field, the data objects in which they are pre-established, are met.
Process Flowchart
The flowchart shown in FIG. 3 will be used to explain the operations of the above-described information processing device 500 .
When processing commences in Step 5401 , visual field data is updated in Step 5402 . Specifically, the visual field data 513 is updated by the visual-field-data updating module 511 based on instructions relating to visual field movement inputted from the input device 501 .
In Step S 403 a frame memory region ( 506 ) for depicting a data object based on the visual field in a virtual space is initialized.
In Step S 404 , based on visual field data and object data, the data object to be displayed is decided. Specifically, based on the current visual field data 513 and object data 531 , and giving consideration to distance from viewpoint and link relation with other data objects, a data object that is present within the visual field is selected as the data object to be displayed. A plurality of data objects to be displayed can be selected.
In Step S 405 , determination is made of whether there are any data objects to be displayed that have not been displayed. If it is determined that there are data objects that have not yet been displayed, control proceeds to Step S 406 ; if it is determined that there are no data objects that have not been displayed, control proceeds to Step 5409 .
In Step S 406 , one data object is selected from among the data objects that have not yet been displayed; based on visual field data 513 and object data 531 , a display image of that data object is generated and depicted on the corresponding region of the frame memory 506 via the display-image synthesizing module 519 .
In Step S 407 , it is determined whether the data object selected in Step S 406 fulfills the conditions for execution of a visual-field-shift-linked process defined in the visual-field-shift-linked process content-defining data 534 . For example, if the data “object is present on an axial line that passes through the center of the display screen, and it appears in a size that is at least one-third of the display screen, it is determined that the conditions for executing the visual-field-shift-linked process are met, and control proceeds to Step S 408 ; if the conditions are not met, control returns to Step S 405 .
In Step S 408 , based on the visual field data 513 , object placement data 532 and visual-field-shift-linked process content-defining data 534 , the visual-field-shift-linked to process is executed. If in the visual-field-shift-linked process content data, there are instructions for information display on the display screen, display content is prepared by the visual-field-shift-linked information displaying module 518 and depicted on the corresponding region in the frame memory 506 via the display-image synthesizing module 519 . Thereafter, control proceeds to Step S 405 .
In Step S 409 , the contents of the frame memory 506 are outputted to the display device 507 .
In Step S 410 , it is determined whether or not to conduct a process for the next display-image frame. If the process for the next display-image frame is to be conducted, control proceeds to Step S 402 ; if not, control proceeds to Step S 411 and the processends.
The geometric relation between a visual field and data object in a three-dimensional virtual space can be represented, for example, as in FIG. 4 .
A data object 605 placed within a three-dimensional virtual space will have its display conditions changed based on its relationship with a current viewpoint 601 . As shown in the figure, the region within a pyramid having the viewpoint 601 as apex is the visual field displayed on the display screen. When the visual field changes because of shift of the viewpoint 601 and changes in the angle of elevation, the position of data object 605 relative to the visual field changes, avid the display screen changes smoothly.
The determination of whether condition have been met for execution of the visual-field-shift-linked process, said determination to be made in the process-execute conditions judging module 521 , can be determination of whether the relationship between visual field coordinate system 603 having viewpoint 601 as its origin and local coordinate system 604 having as its origin the central point of data object 605 meets specific conditions.
Data Object Link Structure
One example of the link structure of data objects to be displayed will be explained using the schematic diagram of FIG. 7 .
Visual-field-shift-linked processes 221 through 226 are attendant on data objects 201 through 206 concatenatedly linked by links 212 through 216 .
In the example shown, links 212 and 213 for data objects 202 and 203 are provided in data object 201 , attendant on which is a visual-field-shift-linked process 221 for displaying a message. Links 214 and 215 for objects 204 and 205 are provided in data object 202 , attendant on which is a visual-field-shift-linked process 222 for displaying a modal dialogue.
A visual-field-shift-linked process 223 for activating application X is attendant on data object 203 . A link 216 for data object 207 is provided in data object 204 , attendant on which is a visual-field-shift-linked process 224 for displaying document A in a different window.
A visual-field-shift-linked process 225 for displaying a modeless dialogue is attendant on data object 205 . A visual-field-shift-linked process 226 for displaying 25 document B in a different window is attendant on data object 206 .
When data objects 201 through 206 , which are to be displayed, meet predefined conditions for execution of visual-field-shift-linked processes 221 through 226 , these visual-field-shift-linked processes 221 through 226 are executed.
FIGS. 8 through 14 show examples of display screens for cases where viewpoint is shifted with regard to a group of data objects to be displayed, causing the visual field to shift.
FIG. 8 shows a case where display of a message is linked to movement of the visual field.
In display example 311 at (A) in FIG. 8 , data objects 201 , 202 and 203 are displayed. In this state, none of the data objects 201 through 203 have met the conditions for executing their respective visual-field-shift-linked processes.
Display example 312 at (B) in FIG. 8 shows a state where the viewpoint has been moved forward, causing the entire visual field to advance, and the data objects 201 through 203 are displayed larger than in display example 311 . At such time, the conditions for executing visual-field-shift-linked process 221 attendant on data object 201 have been met, and so a message 231 is displayed.
Display example 313 at (C) in FIG. 8 shows a state where the viewpoint has been moved further forward from display example 312 ; the data objects 201 through 203 are displayed even larger than in the display example 312 . At this time, the conditions for executing visual-field-shift-linked process 221 attendant on data object 201 are no longer met, and so the message ceases to be displayed.
FIG. 9 shows a case where display of a modal dialogue is linked to movement of visual field. As used herein, a modal dialogue is a dialogue that, while it is being displayed, accepts no operations other than operations relating to the dialogue.
Display example 321 at (A) in FIG. 9 shows a state that is the same as in (C) in FIG. 8 ; data object 202 is displayed in the center foreground. Data objects 204 and 205 are linked to this data object 202 ; however, these are not yet displayed in this display example 321 .
The display example 322 at (B) in FIG. 9 shows a state where the viewpoint has been moved slightly forward from the state in the display example 321 ; the conditions are met for execution of visual-field-shift-linked process 222 attendant on data object 202 , and a modal dialogue 232 is displayed. The modal dialogue in this example displays a box for inputting a password, an OK function button and a cancel function button. In this state, visual-field-shift-linked process-executing module 517 is constituted to block any instructions relating to movement of visual field, and no operations are accepted other than inputting a determined password in the password input box and clicking on the OK function button; or clicking on the cancel function button.
When the proper password is inputted in the modal dialogue 232 of the display example 322 and the OK function button is clicked, visual-field-shift-linked process-executing module 517 ceases to block visual field movement instructions, and movement of visual field becomes possible again, and data objects 204 and 205 linked from data object 202 can now be displayed. This brings about the state shown in display example 323 at (C) in FIG. 9 .
FIG. 10 shows a case where the display of information relating to a data object is linked with movement of visual field. As used herein, information relating to a data object is, for example, a web page relating to a data object to be displayed. In this example, information relating to a data object is displayed in a document display window 233 opened in front of a data object display image in the visual field of a virtual space on a display screen.
In display example 331 at (A) in FIG. 10 , the visual field has been advanced even further than in display example 323 at (C) in FIG. 9 , and the data objects 202 and 204 are displayed.
The display example 332 at (B) in FIG. 10 shows a state where the visual field has been moved slightly forward in comparison to display example 331 ; data object 204 is displayed large, and data object 206 linked with data object 204 is also displayed. In addition the conditions have been met for execution of visual-field-shift-linked process 224 attendant on data object 204 ; a document display window 233 is displayed in the foreground, and document A is displayed in this window.
The display example 333 at (C) in FIG. 10 shows a state where the visual field has been moved slightly forward in comparison to display example 332 ; the data objects 204 and 206 are displayed slightly larger. At this time, because the conditions for execution of visual-field-shift-linked process 224 have remained met, document A of the document display window 233 continues to be displayed. The document display window 233 , the display position and size of which are not linked to visual field and thus do not change, is displayed in a fixed position on the display screen. The document display window 233 may be constituted so that the position thereof changes according to the display position of an important data object to be displayed, so as to avoid the area where such data object is being displayed.
The display example 334 at (D) in FIG. 10 shows a state where the visual field has been moved slightly forward in comparison to display example 333 ; data object 206 is displayed large. At this time, the conditions are met for execution of visual-field-shift-linked process 226 attendant on data object 206 , and in place of document A document B is displayed in the document window 233 .
FIG. 11 shows a case where a display image of a data object based on the visual field within a virtual space is displayed in a data object display window 234 ; in this figure, data object-related information linked to the movement of visual field is displayed, as in FIG. 10 .
In the display example 341 at (A) in FIG. 11 , data object 202 to be displayed is displayed in the data object display window 234 . When the visual field of the data object display window 234 in display example 341 is moved forward so that the conditions are met for execution of visual-field-shift-linked process 224 attendant on data object 204 , the document display window 233 pops up and the document A is displayed, as shown in display example 342 at (B) in FIG. 11 . Similarly, when the conditions are met for execution of visual-field-shift-linked process 226 attendant on data object 206 , document B is displayed within the document display window 233 , as shown in display example 343 at (C) in FIG. 11 .
FIG. 12 shows an example of display image and related information of a data object based on the visual field in a virtual space being displayed in a separate frame within a browser window 235 on the display screen. In this case, too, as with FIG. 10 and FIG. 11 , a case is shown where data object-related information linked to visual field movement is displayed.
In display example 351 at (A) in FIG. 12 , a web browser such as Microsoft Internet Explorer™ is used, and document S is displayed within the browser window 235 .
The display example 352 at (B) in FIG. 12 shows a state where in the document S displayed in display example 351 , a link that calls up the next display has been clicked. Specifically, data object display frame 236 and document display frame 237 are displayed within the browser window 235 ; and data object 202 and others are displayed based on a visual field defined within a virtual space, and document T is displayed within the document display frame 237 .
The display example 353 at (C) in FIG. 12 shows a state where the visual field is moved slightly forward from the state in the data object display frame 236 of the display example 352 ; data object 204 is displayed large, and the conditions are met for execution of visual-field-shift-linked process 224 attendant on data object 204 , and document T in the document display frame 237 is replaced by document A.
The display example 354 at (D) in FIG. 12 shows a state where the visual field is moved slightly forward from the state in the data object display frame 236 of the display example 353 ; data object 206 is displayed large, and the conditions are met for execution of visual-field-shift-linked process 226 attendant on data object 206 , causing document A in the document display frame 237 to be replaced by document B.
FIG. 13 shows an example of display of modeless dialogue being linked to visual field movement. As used here, modeless dialogue is a dialogue such that operations not related to the dialogue are permitted even when the dialogue is displayed.
In the display example 361 at (A) in FIG. 13 , the data objects 202 , 204 and 205 are displayed.
The display example 362 at (B) in FIG. 13 shows a state where the visual field is moved slightly forward from the state in display example 361 ; data object 205 is displayed large, and the sample video image included in data object 205 is a still image. In this case the conditions are met for execution of visual-field-shift-linked process 225 attendant on data object 205 , and so a modeless dialogue 238 is displayed. The modeless dialogue 238 in this example has a play button for giving instructions to play the video, making possible the playing of the video, a sample of which is displayed as a still image. The state where this modeless dialogue 238 is displayed differs from the state where a modal dialogue is displayed, as it is possible to move the visual field in this state.
The display example 363 at (C) in FIG. 13 shows the image displayed when the play button of the modeless dialogue 238 in the display example 362 has been clicked, and a video image is played on data object 205 . In addition, as shown in the figure, while the video image is being played, there is display of a modeless dialogue having a stop button for stopping the video image.
The display example 364 at (D) in FIG. 13 shows a state where the visual field has been moved slightly forward from display example 363 ; data object 205 is displayed 10 slightly larger, and the play of the video image continues.
FIG. 14 shows an example of the execution of an application linked to visual field movement.
In the display example 371 at (A) in FIG. 14 , the data objects 201 , 202 and 203 are displayed.
The display example 372 at (B) in FIG. 14 shows a state where the visual field has been moved slightly forward from the display example 371 ; data object 203 is displayed large, and the conditions are met for execution of the 223 attached to data object 203 , causing the display of the modeless dialogue 239 for confirming whether to activate the application. This modeless dialogue 239 has an OK function button for activating the application and a cancel button; when the OK function button is clicked, the application is activated.
As shown at (C) in FIG. 14 , when the OK function button is clicked, the modeless dialogue 239 is no longer displayed; in its place the application window 240 appears, and it is now possible to use the application.
OTHER EMBODIMENTS
In the above-described embodiments, determination of whether conditions for execution of the visual-field-shift-linked processes have been met is based on the geometric relationship between the visual field and the various data objects; other conditions, however, may be used. For example, priority values may be computed for all data objects to be displayed, the data object with the highest priority value is deemed the representative object, and determination of whether execution conditions have been met for the visual-field-shift-linked processes is made only for the representative object. Alternatively, conditions may be set that are unrelated to visual field movement.
For example, when a data object is positioned in the middle of the screen, and the size at which it appears is at least a predetermined proportion of the screen width (for example, at least one third), the visual-field-shift-linked process is executed. In such a case, if there are a plurality of data objects that meet execution conditions, priority in execution can be given starting those data objects that have a low order in the link relationship.
The present invention allows the viewing of multiple data objects placed in a virtual space as a visual field defined in that virtual space is fluidly shifted; the present invention also allows the display of additional information relating to a data object to be displayed, provides means for when dialogue with a user is required, and allows for the execution of application programs linked to data objects and related thereto.
Only selected embodiments have been chosen to illustrate the present invention. To those skilled in the art, however, it will be apparent from the foregoing disclosure that various changes and modifications can be made herein without departing from the scope of the invention as defined, in the appended claims. Furthermore, the foregoing description of the embodiments according to the present invention is provided for illustration only, and not for limiting the invention as defined by the appended claims and their equivalents.
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A configuration is presented that enables viewing a plurality of data objects situated in a virtual space as the visual field defined in the virtual space is changed smoothly; and that at the same time enables: supplemental information in connection with displayed data objects to be displayed; information in connection with displayed data objects to be displayed in more detail; means for dialogue with a user to be provided in situations where required; and application programs linked to the display of information and associated with that information to be executed. Included are: a step of accepting virtual-viewpoint position changes; a step of continuously changing visual field based on the virtual-viewpoint position changes, and uninterruptedly changing the display of a data object positioned within the visual field; a step of determining whether a data object positioned within the visual field satisfies predetermined geometric conditions for the visual field; and in respect of a data object that satisfies the predetermined geometric conditions, a step of executing a process preset in that data object.
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FIELD
[0001] The present invention is directed to the area of door fabrication and methods of making the doors. The present invention is also directed to flush architectural doors formed using post-consumer materials, as well as methods of making the flush architectural doors.
BACKGROUND
[0002] There is a general desire to reduce the costs associated with construction projects (e.g., commercial, residential, industrial, or the like). These costs may include, for example, money, time, materials, or the environmental impact associated with the construction projects. One way to reduce one or more of these costs is to reuse materials, whenever possible. For example, prior to demolition of a preexisting structure, at least some hardware and/or materials may be removed from the structure and resold or reused (either in whole or in part) in another structure, either at the site of the demolition or at another location.
[0003] Flush architectural doors are commonplace in many buildings (e.g., commercial, residential, industrial, or the like). When new buildings are built, new flush architectural doors are commonly used within the new buildings. Flush architectural doors are commonly formed using wood or wood-based products. Currently, 95%-100% of commercial-grade flush architectural wooden doors are produced by harvesting of living wood. Unfortunately, when many buildings are demolished, flush architectural wooden doors from within the buildings are destroyed during the demolition process.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] Non-limiting and non-exhaustive embodiments of the present invention are described with reference to the following drawings. In the drawings, like reference numerals refer to like parts throughout the various figures unless otherwise specified.
[0005] For a better understanding of the present invention, reference will be made to the following Detailed Description, which is to be read in association with the accompanying drawings, wherein:
[0006] FIG. 1A is a schematic perspective view of one embodiment of a door formed, in part, by disposing rails, styles, and at least one skin over a core formed from post-consumer materials, according to the invention;
[0007] FIG. 1B is a schematic perspective view of one embodiment of skins removed from the door of FIG. 1A , thereby exposing inner portions of the door, the inner portions including rails and styles surrounding a core formed from post-consumer materials, according to the invention; and
[0008] FIG. 2 is a flow chart illustrating one embodiment of a method for manufacturing the door of FIG. 1A using a core formed from post-consumer materials, according to the invention.
DETAILED DESCRIPTION
[0009] The present invention is directed to the area of door fabrication and methods of making the doors. The present invention is also directed to flush architectural doors formed using post-consumer materials, as well as methods of making the flush architectural doors.
[0010] At least some flush architectural wooden doors (“doors”) are formed from skins styles, and rails disposed over a core. Skins, styles, and rails can be formed from any suitable materials including, for example, wood, wood-based products, gypsum, or the like or combinations thereof. Cores can be formed from any suitable material including, for example, woodchips, sawdust, wood shavings, particle board, plywood, resin (or one or more other suitable binding materials), stud grade lumber, structural lumber, laminated strand lumber (“LSL”), gypsum, fiberglass, agrifiber, or the like or combinations thereof.
[0011] As herein described, a system and method for making doors includes using post-consumer (i.e., recycled) materials. The post-consumer materials include cores from previously-used doors (e.g., doors formerly used in commercial, residential, or industrial settings, or the like or combinations thereof). It may be advantageous to form doors that include cores from previously-used doors. Doors formed from recycled cores may be more environmentally friendly than other doors because the doors formed from recycled materials do not involve harvesting new lumber to form the cores. In addition to reducing the amount of new wood or wood-based materials needed to form a new door, using recycled cores may additionally reduce the amount of post-construction wood debris discarded from construction sites (or demolition sites). Moreover, using doors formed from recycled cores in a construction project may enable credits (or points, or the like) to be earned under one or more environmental-based accreditation systems, such as the Leadership in Energy and Environmental Design (“LEED”) certification system.
[0012] FIG. 1A is a schematic perspective view of one embodiment of a door 102 formed using post-consumer materials. The door 102 includes a top rail 108 , an opposing bottom rail 110 , a first style 112 , and an opposing second style 114 . A first skin 104 and an opposing second skin 106 are disposed over the rails 108 , 110 and the styles 112 , 114 .
[0013] FIG. 1B is a schematic perspective view of one embodiment of the door 102 with the first skin 104 and the second skin 106 removed to expose inner portions of the door 102 . The exposed inner portions of the door 102 include a core 160 disposed between the rails 108 , 110 and the styles 112 , 114 . The core 160 is formed from previously-used (i.e., recycled) materials. Optionally, one or more of the styles 112 , 114 may include one or more mortises 130 for receiving hardware (e.g., mounting hardware for a latch, a knob, a lock, hinges, or the like).
[0014] In at least some cases, the core 160 may be coupled to one or more of the rails 108 , 110 or the styles 112 , 114 using adhesive, mortise and tenon joints, or the like or combinations thereof. The skins 104 , 106 can be coupled to the recycled core 160 and one or more of the rails 108 , 110 or the styles 112 , 114 in any suitable manner including, for example, one or more adhesives, or the like.
[0015] The rails 108 , 110 and the styles 112 , 114 can each be any suitable thickness. In at least some embodiments the rails 108 , 110 have thicknesses of no less than one-and-a-half inches. In at least some embodiments the rails 108 , 110 have thicknesses of no more than and eight inches. In at least some embodiments the styles 112 , 114 have thicknesses of no greater than two-and-a-half inches. The skins 104 , 106 can each be any suitable thickness. In at least some embodiments the skins 104 , 106 have thicknesses of no greater than a half inch. In at least some embodiments, the skins 104 , 106 have thicknesses of approximately one-sixteenth of an inch.
[0016] In some cases, one or more of the rails 108 , 110 , the styles 112 , 114 , and the skins 104 , 106 may include one or more layers of materials, such as a substrate and an outer edge. For example, the rail 108 may include a substrate 108 a (e.g., medium-density or high-density fiberboard, or the like) and an outer edge 108 b (e.g., hardwood, softwood, or the like). Similarly, one or more of the styles 112 , 114 may include a substrate 112 a, 114 a, respectively, and an outer edge 112 a, 112 b, respectfully. The skins 104 , 106 may include substrates (e.g., medium-density fiberboard, or the like) and outer edges.
[0017] The edges 108 b, 112 b, and 114 b can be any suitable thickness. In at least some embodiments the edges 108 b, 112 b, and 114 b have thicknesses that are no less than three-eights of an inch. In at least some embodiments, the edges 108 b, 112 b, and 114 b have thicknesses that are no greater than one-and-one-quarter inches.
[0018] In at least some cases, one or more portions of the door 102 can be omitted. For example, in at least some embodiments the door 102 may not include one or more substrates (e.g., substrate 108 a of the rail 108 , or the like). In which case, the outer edge 108 b can be disposed directly against the core 160 .
[0019] The recycled core 160 may form the majority of the weight of the door 102 (excluding any post-manufacturing hardware, such as knobs, latches, locks, strike plates, fasteners, or the like, that may be subsequently mounted onto the door 102 ). In some cases, the recycled core 160 may form a majority of the weight of the door 102 . For example, the recycled core 160 may form at least 51%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or more of the weight of the door 102 .
[0020] Forming the door 102 from post-consumer materials may involve one or more of collecting a previously-used door, extracting a core from the previously-used door, and processing the core to form the new door 102 . In some cases, the core may be inspected one or more times to ensure that the core is satisfactory for re-use. Processing the core to form the new door 102 may include re-applying all, or a portion, of one or more of the rails 108 , 110 or the styles 112 , 114 and re-skinning at least one side of the rails 108 , 110 , styles 112 , 114 and extracted core 160 . Optionally, processing the core to form the new door 102 may also include refinishing the new door 102 .
[0021] Previously-used doors can be collected in any suitable manner. For example, previously-used doors can be gathered from a collection site. The collection site can be any suitable location including, for example, a construction project, a demolition location, a previously-used-door drop-off location, or other suitable location.
[0022] Gathered previously-used doors can be transported to an extraction location where the cores of the previously-used doors are extracted. In some cases, the collection site and the extraction location are the same location. Extracting the core may include one or more of: removing any skins disposed over the core, and removing all, or a portion of each of the rails and the styles disposed around the core. The skins can be removed from the core in any suitable manner, including using a planer, an abrasive sander, or the like. The rails and the styles (or portions thereof) can be removed in any suitable manner including, for example, ripping the rails and styles from the core. In some cases, extracting the core may include making one or more preliminary cuts through a portion of the door to determine the thicknesses of one or more of the skins, rails, or styles.
[0023] The cores may be inspected one or more times, including before, during, or after extraction. In some cases, the inspection may occur at the collection site. In other cases, the inspection may occur at the extraction site, or at some other suitable location. Inspection may include recording information about the door and/or the core. The recorded information may include, for example, one or more door dimensions, observable door features (e.g., cutouts, or the like), fire ratings, general physical conditions (e.g., integrity, moisture, density, warpage, defects, damage, or the like), core type, style or rail configuration, skin application, existence of potentially-flammable or toxic materials, or the like or combinations thereof
[0024] Once the cores are extracted, the cores can be re-styled, re-railed, and re-skinned. In some cases, the doors 102 may additionally be machined, for example, to facilitate installment of new hardware. In some cases, the doors 102 may additionally be refinished. Refinishing the doors 102 may include at least one of staining, painting, varnishing, or the like to one or more portions of the doors 102 . Refinishing the doors 102 may additionally include applying one or more protective coatings, sealants, or adhesives to one or more portions of the doors 102 . In at least some embodiments, refinishing is performed using one or more ultraviolet-light-curing materials. When adhesives are used (e.g., during re-styling, re-railing, re-skinning, refinishing, or the like), the adhesives can, optionally, be No Added Urea Formaldehyde (“NAUF”) compounds. It may be advantageous to use NAUF compounds in order to reduce, or even eliminate, off gassing. Using NAUF compounds may provide additional credit for a construction project seeking a desired accreditation, such as a LEED accreditation. In some cases, one or more portions of the fabrication of the doors 102 may be performed by one or more licensed door manufacturers.
[0025] Currently, one or more agencies implement tracking systems that trace timber from designated locations along a supply chain. For example, the Forest Stewardship Council (“FSC”) traces products from certified forests throughout the supply chain to ensure that any claims on the origin of the product are credible and verifiable. The FSC tracking system includes a voluntary chain-of-custody certification that enables manufacturers and traders to demonstrate that timber comes from a forest that is responsibly managed in accordance with specific criteria. In some cases, a valid chain-of-custody certification may be necessary for receiving approval for using wood products in a particular project.
[0026] In some cases, the door 102 with the recycled core 160 may include chain-of-custody information that validates the origin of the core 160 as being a post-consumer product. The chain-of-custody information may include one or more of the date or location of collection of the core. The chain-of-custody information can be recorded and attached (e.g., stamped, written, etched, stapled, implanted via a chip, or the like) to a core (or to some other portion of the door 102 or to some other portion of the rail of the door) subsequent to extraction. In at least some cases, the door 102 may be useable on construction jobs that would otherwise be limited to doors having FSC chain-of-custody certification. In at least some embodiments, the chain-of-custody information can be used to create a chain-of-custody certificate.
[0027] The chain-of-custody information may additionally include other relevant information including, for example, the type of core (e.g., particle core, strand core, mineral core, stave core, or the like), the dimensions of the core, a physical description of the door from which the core was extracted, details regarding the age or origination of the door from which the core was extracted, the name or other relevant identification information of the collecting entity, the general condition of the door from which the core was extracted, or the like.
[0028] In some instances, the extracted core may be certified by one or more certifying bodies including, for example, the Architectural Woodwork Institute (“AWI”), the Window & Door Manufacturers Association (“WDMA”), American National Standards Institute (“ANSI”) or the like or combinations thereof, prior to being re-railed, re-styled, and re-skinned. In some cases, the certification process may be very similar to a certification process performed on a new core.
[0029] FIG. 2 is a flow chart illustrating a method for forming the door 102 using at least some post-consumer materials. In step 202 , a previously-used door is collected. In step 204 , a core is extracted from the previously-used door. In optional step 206 , the core is inspected. In step 208 , the core is re-railed and re-styled. In step 210 , at least one skin is disposed over the core, rails, and styles. Optionally, in step 212 the door is machined. Optionally, in step 214 the door is refinished.
[0030] The above specification, examples and data provide a description of the manufacture and use of the composition of the invention. Since many embodiments of the invention can be made without departing from the spirit and scope of the invention, the invention also resides in the claims hereinafter appended.
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A method for forming a flush architectural wooden door using at least one post-consumer material includes collecting a previously-used door from a collection site. The previously-used door includes a core having a first major surface, a second major surface opposite to the first major surface, and a perimeter extending around the opposing major surfaces. The core is extracted from the previously-used door. Rails and styles are applied to a perimeter of the extracted core. A first skin is applied over the first major surface of the extracted core and applied rails and styles. The extracted core, rails, styles, and first skin have a collective weight. The extracted core forms over half of that collective weight.
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CROSS-REFERENCE TO RELATED PATENT APPLICATION
[0001] This application claims priority to and the benefit of Korean Patent Application No. 10-2005-0094935, filed on Oct. 10, 2005, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to an oligomer solid acid and a polymer electrolyte membrane using the same, and more particularly, to an oligomer solid acid which provides high ionic conductivity and a polymer electrolyte membrane with excellent ionic conductivity and low methanol crossover.
[0004] 2. Description of the Related Art
[0005] A fuel cell is an electrochemical device which directly transforms chemical energy of both oxygen and hydrogen contained in a hydrocarbon material such as methanol, ethanol, and natural gas into electric energy. The energy transformation process of a fuel cell is very efficient and environmentally-friendly.
[0006] Fuel cells can be classified into Phosphoric Acid Fuel Cells (PAFC), Molten Carbonate Fuel Cells (MCFC), Solid Oxide Full Cells (SOFC), Polymer Electrolyte Membrane Fuel Cells (PEMFC), and Alkaline Full Cells (AFC) according to the type of electrolyte used. All fuel cells operate on the same principle, but the type of fuel used, operating temperature, the catalyst used and the electrolyte used are different. In particular, a PEMFC is capable of being used in small-sized stationary power generation equipment or a transportation system due to its low operating temperature, high output density, rapid start-up, and prompt response to the variation of output demand.
[0007] The core part of a PEMFC is a Membrane Electrode Assembly MEA. An MEA generally comprises a polymer electrolyte membrane and an electrode attached to each side of the polymer electrolyte membrane, which independently act as a cathode and an anode.
[0008] The polymer electrolyte membrane acts as a separator blocking the direct contact between an oxidizing agent and a reducing agent, and electrically insulates the two electrodes while conducting protons. Accordingly, a good polymer electrolyte membrane has high proton conductivity, good electrical insulation, low reactant permeability, excellent thermal, chemical and mechanical stability under normal conditions of fuel cell operation, and a reasonable price.
[0009] In order to meet these requirements, various types of polymer electrolyte membranes have been developed, and, in particular, a highly fluorinated polysulfonic acid membrane such as a NAFION™ membrane is a standard due to excellent durability and performance. However, for excellent performance, the NAFION™ membrane should be sufficiently humidified, and to prevent moisture loss, the NAFION™ membrane should be used at a temperature of 80° C. or below. Also, since, a carbon-carbon bond of the main chain is attacked by oxygen (O 2 ), the NAFION™ membrane is not stable under the operating conditions of a fuel cell.
[0010] Moreover, in a Direct Methanol Fuel Cell (DMFC), an aqueous methanol solution is supplied as a fuel to the anode and a portion of unreacted aqueous methanol solution is permeated to the polymer electrolyte membrane. The methanol solution that permeates the polymer electrolyte membrane causes a swelling phenomenon in an electrolyte membrane to diffuse to a cathode catalyst layer. Such a phenomenon is referred to as ‘methanol crossover’, the direct oxidization of methanol at the cathode where an electrochemical reduction of hydrogen ions and oxygen occurs, and thus the methanol crossover results in a drop in the electric potential of the cathode, thereby causing a significant decline in the performance of the fuel cell.
[0011] This issue is common in other fuel cells using a liquid fuel in which a polar organic fuel other than methanol is included.
SUMMARY OF THE INVENTION
[0012] One embodiment of the present invention provides an oligomer solid acid which can provide ionic conductivity to a polymer electrolyte membrane and is not separated easily from the polymer electrolyte membrane.
[0013] Another embodiment of the present invention provides a polymer electrolyte membrane including the oligomer solid acid which shows excellent ionic conductivity, even without humidifying, and low methanol crossover.
[0014] Yet another embodiment of the present invention provides a Membrane Electrode Assembly (MEA) including the polymer electrolyte membrane.
[0015] An embodiment of the present invention provides a fuel cell including the polymer electrolyte membrane.
[0016] According to an embodiment of the present invention, an oligomer solid acid is provided including: (a) a main chain having a degree of polymerization of 10 to 70; and (b) a side chain having the structure represented by Formula 1 bonded to a repeating unit of the main chain:
-E 1 - . . . -E i - . . . -E n Formula 1
where each E i included in E 1 through E n−1 is independently one of the organic groups represented by Formula 2 through Formula 6,
where each E i+1 of Formula 4 through Formula 6 can be independently the same or different, the number of E i+1 of the (i+1) th generation bonded with E i of the i th generation is the same as the number of available bonds existing in E i , n is an integer in the range of 2 to 4 and indicates the generation of a branching unit; and E n is one of —SO 3 H, —COOH, —OH, and —OPO(OH) 2 .
[0017] It should be apparent to one of skill in the art that the individual side chains of the side chains of Formula 1 are not limited to straight chain branches, but rather, each branch may have further branches depending on the number of E i +1 bonding sites for a particular E i organic group at the i th level of the corresponding dendrimer.
[0018] According to another embodiment of the present invention, a polymer electrolyte membrane is provided including at least one polymer matrix having an end group selected from the group consisting of —SO 3 H, —COOH, —OH, and —OPO(OH) 2 at the terminal of a side chain, and the oligomer solid acid uniformly distributed through the polymer matrixes.
[0019] According to another embodiment of the present invention, a Membrane Electrode Assembly (MEA) is provided including: a cathode having a catalyst layer and a diffusion layer; an anode having a catalyst layer and a diffusion layer; and an electrolyte membrane interposed between the cathode and the anode, the electrolyte membrane including the polymer electrolyte membrane of the present invention.
[0020] According to another embodiment of the present invention, a fuel cell is provided including: a cathode having a catalyst layer and a diffusion layer; an anode having a catalyst layer and a diffusion layer; and an electrolyte membrane interposed between the cathode and the anode, the electrolyte membrane including the polymer electrolyte membrane of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] The above and other embodiments of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings in which:
[0022] FIG. 1 is a graph showing the results of a Nuclear Magnetic Resonance (NMR) analysis performed to identify the structure of a compound in Formula 19;
[0023] FIG. 2 is a graph showing the result of a NMR analysis performed to identify the structure of a compound in Formula 20;
[0024] FIG. 3 is a graph showing the result of a NMR analysis performed to identify the structure of a compound in Formula 22;
[0025] FIG. 4 is a graph showing the results of a Fourier Transform Infrared Spectroscopy (FT-IR) analysis performed to identify the structure of a compound in Formula 23;
[0026] FIG. 5 is a fuel cell according to an embodiment of the invention; and
[0027] FIG. 6 is a Membrane Electrode Assembly (MEA) according to an embodiment of the invention.
DETAILED DESCRIPTION
[0028] The present invention will now be described more fully with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown. The invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein.
[0029] An oligomer solid acid according to an embodiment of the present invention includes a main chain having a degree of polymerization of 10 to 70; and a side chain having the structure represented by Formula 1 bonded to a repeating unit of the main chain:
-E 1 - . . . -E i - . . . -E n Formula 1
where each E i included in E 1 through E n−1 is independently one of the organic groups represented by Formula 2 through Formula 6,
where each E i+1 of Formula 4 through Formula 6 can be independently the same or different, the number of E i+1 of the (i+1) th generation bonded with E i of the i th generation is the same as the number of available bonds existing in E i , n is an integer in the range of 2 to 4 and indicates the generation of a branching unit; and E n is one of —SO 3 H, —COOH, —OH, and —OPO(OH) 2 .
[0030] If the oligomer solid acid of one embodiment is distributed between polymer matrixes, outflow due to swelling hardly occurs since the oligomer solid acid has a significantly large size. Also, the oligomer solid acid of an embodiment provides ionic conductivity to a polymer electrolyte membrane since an acidic functional group such as —COOH, —SO 3 H, or —OPO(OH) 2 attached to a terminal provides high ionic conductivity.
[0031] In the main chain of the oligomer solid acid according to another embodiment, the degree of polymerization may be 10 to 70, for example, 20 to 50. When the degree of polymerization of the main chain is less than 10, the molecular weight of the whole oligomer molecule in which the side chain is included may be less than 10,000. In this case, the size of the molecule is too small, and thus it is likely that the oligomer solid acid will outflow. When the degree of polymerization of the main chain is greater than 70, the molecular weight of the whole oligomer molecule in which the side chain is included may exceed 40,000. In this case, the properties of the oligomer solid acid may be difficult to control and the domain size of the solid acid formed by a phase separation from a matrix in the polymer membrane is significantly large.
[0032] In one embodiment, the repeating unit of the main chain may be the repeating unit of polystyrene, polyethylene, polyimide, polyamide, polyacrylate, polyamic ester or polyaniline.
[0033] In particular, the repeating unit of the main chain may be a unit represented by one of Formula 7 through Formula 9, but is not limited thereto.
[0034] The side chain which bonds to the repeating unit of the main chain may be a chain represented by one of Formula 10 through Formula 15 below, but is not limited thereto.
Here, R is one of —SO 3 H, —COOH, —OH, and —OPO(OH) 2 .
[0035] The molecular weight of the oligomer solid acid according to one embodiment may be 10,000 to 40,000. When the molecular weight is below 10,000, the size of the molecule is too small, and thus it is likely that the oligomer solid acid will outflow. When the molecular weight is above 40,000, the properties of the oligomer solid acid may be difficult to control and the domain size of the solid acid formed by a phase separation from a matrix in the polymer membrane is significantly large.
[0036] The dendrimer solid acid according to an embodiment of the present invention will now be described in greater detail with reference to a process of manufacturing the dendrimer solid acid represented by Reaction Schemes 1 and 2. The method is provided to facilitate the understanding of the present invention, but the present invention is not limited by the reaction schemes set forth herein.
[0037] According to one embodiment, first, as shown in Reaction Scheme 1, a monomer forming the side chain can be synthesized.
[0038] A side chain unit having multiple generations can be manufactured by repeating the method shown in Reaction Scheme 1.
[0039] Then, as shown in Reaction Scheme 2, the above side chain unit is reacted with a compound forming the main chain to manufacture the oligomer solid acid according to an embodiment of the present invention.
[0040] In an embodiment, p is an integer determined such that the molecular weight of the compound which forms the main chain is 2,000 through 8,000.
[0041] In order to have a functional group such as —COOH, —OH, or —OPO(OH) 2 at the terminal of the oligomer solid acid, a structure in which the functional group such as —COOH, —OH, or —OPO(OH) 2 is protected by an alkyl group during the branching structure synthesis. That is, the functional group is included in a benzyl halide compound having a structure of —COOR, —OR, or —OPO(OR) 2 . Then, the polymer with the low molecular weight is prepared and the oligomer solid acid can be subsequently manufactured by detaching an alkyl group. In one embodiment, R is, for example, a monovalent C 1-5 alkyl group.
[0042] A polymer electrolyte membrane according to an embodiment of the present invention will now be described.
[0043] A polymer electrolyte membrane according to an embodiment of the present invention includes at least one polymer matrix having an end group selected from the group consisting of —SO 3 H, —COOH, —OH, and —OPO(OH) 2 at the terminal of a side chain, and an oligomer solid acid uniformly distributed through the polymer matrixes.
[0044] The polymer matrixes may be a polymer material selected from the group consisting of polyimide, polybenzimidazole, polyethersulfone, and polyether-ether-ketone.
[0045] The polymer electrolyte membrane can have ionic conductivity since the oligomer solid acid according to an embodiment of the present invention is uniformly distributed throughout the polymer matrix. That is, both acidic functional groups at the terminal of the side chain of the polymer matrix and acidic functional groups existing on the surface of the oligomer solid acid interact together to provide high ionic conductivity.
[0046] Conventionally, a large amount of an ionically conductive terminal group such as a sulfone group is attached to a polymer forming matrix in a conventional polymer electrolyte membrane, thereby causing swelling. However, according to an embodiment, in the polymer matrix described herein, only the minimum amount of an ionically conductive terminal group required for ionic conduction is attached to prevent swelling caused by moisture.
[0047] In particular, the polymer matrix herein may be a polymer resin represented by Formula 16 below:
where M is a repeating unit of Formula 17 below,
where Y is a tetravalent aromatic organic group or aliphatic organic group and Z is a bivalent aromatic organic group or aliphatic organic group; X in Formula 16 is a repeating unit of Formula 18 below,
where Y′ is a tetravalent aromatic organic group or aliphatic organic group, Z′ is a tetravalent aromatic organic group or aliphatic organic group, j and k are each independently an integer in the range of 1 to 6, and R 1 is one of —OH, —SO 3 H, —COOH, and —OPO(OH) 2 ; and m and n are each independently in the range of 30 to 5000.
[0048] In an embodiment, the ratio of m to n may be between 2:8 and 8:2, for example, between 4:6 and 6:4. When the ratio of m to n is less than 2:8, swelling and methanol crossover due to water are increased. When the ratio of m to n is greater than 8:2, hydrogen ion conductivity is too low to secure an optimum level of hydrogen ion conductivity even when the solid acid is added.
[0049] For example, M and X, which are repeating units of the polymer resin of Formula 16, may have the structures represented by Formula 24 and Formula 25, respectively:
where j and k are each independently a fixed number in the range of 1 to 6 and R 1 is one of —OH, —SO 3 H, —COOH, and —OPO(OH) 2 .
[0050] The process of manufacturing the polymer matrix according to Formula 16 is not particularly restricted, and may be the process illustrated in Reaction Scheme 3.
[0051] A Membrane Electrode Assembly (MEA) including the polymer electrolyte membrane according to an embodiment of the present invention will now be described. The MEA includes: a cathode having a catalyst layer and a diffusion layer; an anode having a catalyst layer and a diffusion layer; and an electrolyte membrane interposed between the cathode and the anode, the electrolyte membrane including the polymer electrolyte membrane according to an embodiment of the present invention.
[0052] The cathode and anode both having a catalyst layer and a diffusion layer may be those that are well known in the field of fuel cells. Also, the electrolyte membrane includes the polymer electrolyte membrane according to an embodiment of the present invention. The polymer electrolyte membrane according to an embodiment of the present invention can be used alone as an electrolyte membrane or can be combined with another membrane having ionic conductivity.
[0053] A fuel cell according to an embodiment of the present invention including the polymer electrolyte membrane will now be described.
[0054] The fuel cell includes: a cathode having a catalyst layer and a diffusion layer; an anode having a catalyst layer and a diffusion layer; and an electrolyte membrane interposed between the cathode and the anode, the electrolyte membrane including the polymer electrolyte membrane according to an embodiment of the present invention.
[0055] The cathode and anode both having a catalyst layer and a diffusion layer may be those that are well known in the field of fuel cells. Also, the electrolyte membrane includes the polymer electrolyte membrane according to an embodiment of the present invention. The polymer electrolyte membrane according to an embodiment of the present invention can be used alone as an electrolyte membrane or can be combined with another membrane having ionic conductivity.
[0056] In one embodiment, as shown in FIG. 5 , the fuel cell 100 includes a fuel supplier 1 , an oxygen supplier 5 , and a fuel cell stack 7 . The fuel supplier 1 includes a fuel tank 9 for containing a fuel such as methanol and a fuel pump 11 for supplying the fuel to the stack 7 . The oxygen supplier 5 includes an oxygen pump 13 for supplying oxygen from air to the stack 7 . The stack includes a plurality of electricity generating units 19 , each comprising a Membrane Electrode Assembly 21 and separators 23 and 25 . Each Membrane Electrode Assembly 21 comprises a polymer electrode member with an anode on a first side and a cathode on a second side.
[0057] To manufacture the fuel cell, a conventional method can be used, and thus, a detailed description is omitted herein.
[0058] The polymer electrolyte membrane according to an embodiment of the present invention minimizes the methanol crossover by using the polymer matrix which suppresses swelling by minimizing the number of ion conductive terminal groups and significantly improves the ionic conductivity by distributing the oligomer solid acid macromolecules which has ion conductive terminal groups on the surface and a large volume, thereby hardly escaping the polymer matrix in which they are distributed. Accordingly, the polymer electrolyte membrane according to an embodiment of the present invention sustains high ionic conductivity even in non-humidified conditions.
[0059] In an embodiment, as shown in FIG. 6 , a Membrane Electrode Assembly (MEA) of the present invention includes an anode 30 to which a fuel is supplied, a cathode 50 to which an oxidant is supplied, and an electrolyte membrane 130 interposed between the anode 30 and the cathode 50 . The anode 30 can be composed of an anode diffusion layer 31 and an anode catalyst layer 33 and the cathode 50 can be composed of a cathode diffusion layer 51 , and a cathode catalyst layer 53 .
[0060] The present invention will be described in greater detail with reference to the following examples. The following examples are for illustrative purposes only, and are not intended to limit the scope of the invention.
EXAMPLE 1
[0061] 0.38 moles of benzyl bromide, 0.18 moles of 3,5-Dihydroxy benzyl alcohol, 0.36 moles of K 2 CO 3 and 0.036 moles of 18-crown-6 were dissolved in acetone and refluxed at 60° C. for 24 hours. The mixture was cooled to room temperature. Then the acetone was removed by distillation and was extracted using an ethylacetate/sodium hydroxide solution to separate an organic layer from the mixture. The separated organic layer was dried using MgSO 4 and the solvent was distilled and removed. The resulting product was recrystallized with ether/hexane and refined to obtain 37 g of the compound in Formula 19 as a white crystalline solid (Yield: 67%). The structure of compound in Formula 19 was identified using Nuclear Magnetic Resonance (NMR) analysis, and the results are shown in FIG. 1 .
20 g (0.065 moles) of the compound of Formula 19 was dissolved in 50 ml of benzene at 0° C., and then a solution in which 6.4 g (0.0238 moles) of PBr 3 was dissolved in benzene was added dropwise to the resulting product and stirred for 15 minutes. Then, the temperature of the resulting product was raised to an ambient temperature and stirred for 2 hours. The mixture was then put into an ice bath and the benzene was distilled to be removed. After extracting an aqueous phase using ethylacetate, the organic layer was separated and dried using MgSO 4 and the solvent was removed by distillation. The result was recrystallized with toluene/ethanol and was refined to obtain 19 g of the compound in Formula 20 as a white crystalline solid (Yield: 79%). The structure of the compound in Formula 20 was identified using NMR analysis, and the results are shown in FIG. 2 .
8.4 g of the compound of Formula 20 thus synthesized, 2.42 g of commercially available polyhydroxystyrene (PHSt: compound of Formula 21, Mw=3000, manufactured by Nippon Soda, Japan), 2.8 g of K 2 CO 3 and 1.1 g of 18-crown-6 were dissolved in 200 ml of tetrahydrofuran (THF) and refluxed at 60° C. for 24 hours. The reaction mixture was cooled to room temperature. Then the acetone was distilled to be removed and was extracted using a toluene/sodium hydroxide solution to separate a toluene layer from the reaction mixture. The separated toluene layer was dried using MgSO 4 and the toluene was distilled to be concentrated to 50 ml. The result was immersed in ethanol to obtain 8.2 g of the compound of Formula 22 as a white crystalline solid (Yield: 76%). The structure of the compound in Formula 22 was identified using NMR analysis, and the results are shown in FIG. 3 .
5 g of the compound of Formula 22 (oligomer solid acid precursor) thus obtained was completely dissolved in 15 ml of sulfuric acid, and then 5 ml of fumed sulfuric acid (SO 3 60%) was added hereto. The mixture was allowed to react at 80° C. for 12 hours and then precipitated in ether. The precipitate was filtered and then dissolved in water. The resultant was put into a dialysis membrane and refined to obtain the compound of Formula 23. The structure of the compound of Formula 23 was identified using Fourier Transform Infrared Spectroscopy (FT-IR) analysis, and the results are shown in FIG. 4 .
EXAMPLE 2
[0062] 100 parts by weight of the polymer matrix of Formula 16 manufactured as illustrated in Reaction Scheme 3 with the ratio of m to n being 5:5, and 6.7 parts by weight of the oligomer solid acid of Formula 23 were completely dissolved in N-methyl pyrrolidone (NMP) and casted at 110° C. to manufacture a polymer electrolyte membrane.
EXAMPLE 3
[0063] A polymer electrolyte membrane was manufactured according to Example 2, except that 10 parts by weight of the oligomer solid acid in Formula 23 was used.
[0064] The ionic conductivity and methanol crossover were respectively measured for the polymer electrolyte membranes manufactured as in Examples 2 and 3 and a polymer membrane in which a solid acid was not included. The results are illustrated in Table 1.
TABLE 1 Methanol crossover Ionic conductivity (S/cm) (cm 2 /sec) Polymer membrane 2.60 × 10 −6 2.73 × 10 −9 Example 2 1.48 × 10 −4 (after 1 day) 5.51 × 10 −8 Example 3 6.68 × 10 −4 (after 1 day) 4.63 × 10 −8
[0065] As illustrated in Table 1, by adding the oligomer solid acid according to an embodiment of the present invention, methanol crossover is slightly increased and ionic conductivity is greatly increased relative to the increase in methanol crossover. Therefore, when the solid acid according to an embodiment of the present invention is used, ionic conductivity may be greatly improved without affecting methanol crossover. While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims.
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An oligomer solid acid and a polymer electrolyte membrane using the same. The polymer electrolyte membrane includes a macromolecule of oligomer solid acid having an ionically conductive terminal group at its terminal end and the minimum amount of ionically conductive terminal groups required for ion conduction, thus suppressing swelling and allowing a uniform distribution of the oligomer solid acid, thereby improving ionic conductivity. Since the number of ionically conductive terminal groups in the polymer electrolyte membrane is minimized and the polymer matrix in which swelling is suppressed is used, methanol crossover and difficulties of outflow due to a large volume are minimized, and a macromolecule of the oligomer solid acid having the ionically conductive terminal groups on the surface thereof is uniformly distributed. Accordingly, ionic conductivity is high and thus, the polymer electrolyte membrane shows good ionic conductivity even in low humidity conditions.
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This application is a continuation of application Ser. No. 132,044, filed Mar. 30, 1980, now abandoned.
This invention relates to hydraulic controls for variable stroke positive displacement hydraulic motors.
SUMMARY OF THE PRIOR ART
Variable stroke positive displacement pump/motors are known. One prominent manufacturer of such motors is the Sundstrand Corporation of Ames, Iowa, who manufactures such a motor under the names Sundstrand Hydrotransmission. Such a motor is illustrated and will be described with reference to FIG. 1.
Referring to FIG. 1, a variable displacement motor M is illustrated having a drive shaft 14 for driving whatever load the pump is connected to. Typically, hydraulic fluid flows in through a port 16 and out through a port 17. The entire pump turns about shaft 14 and includes a series of rotating pistons 18 within a series of rotating cylinders 19.
Operation of the pump can easily be understood. Cylinders 19 communicate to the hydraulic fluid and the pistons 18 communicate to a tilt box 20, the angle of which varies to vary pump displacement. A plate 22 is provided with a series of left apertures 23 and a series of right apertures 24. Noting that tilt box 20 is tilted at an angle away from the viewer and that the entire system of pistons 18 and cylinders 19 is rotating counterclockwise in the view of FIG. 1, it will be seen that hydraulic fluid flows inwardly through light ports 24 and outwardly through left ports 23.
It remains only to be understood that the angle of tilt box 20 can change responsive to the force acting between a springed biased cylinder 25 and a hydraulic pressure control cylinder 26 across paired trunions 28 (top trunion 28 being the only one shown). By having the respective pistons 25, 26 act upon opposing lever arms at opposite sides of the trunion, the angle of the tilt box plate can be changed. Assuming that the tilt box 20 only changes from a disposition normal to shaft 14 to a disposition angular with respect to shaft 14, driving of the motor in one direction will occur. It is known that such motors readily operate in a reversible mode, by corresponding movement of a tilt box.
Where such motors are used in a master-slave relationship, a known amount of hydraulic leakage occurs. This hydraulic leakage occurs both at the pump providing the initial hydraulic power as well as the motor extracting hydraulic power from the system. Typically, both the hydraulic pump and the driven hydraulic motor incorporate known amounts of fluid loss from their high pressure side to their low case and pressure side. The result is that where pumps are utilized in accordance with the overall design of FIG. 1, unless fluid is added to the low pressure side of the provided hydraulic circuit by a small positive displacement, shaft actuated gear pump, known as a charge pump 30, the inlet of hydraulic fluid will not be sufficient to meet the positive displacement requirements of the pump. Consequently, such motors and/or pumps as illustrated in FIG. 1 are often provided with a charge pump as a standard item of manufacture. While such charge pumps in no way suggest the control mechanism of the following invention, it will become more apparent that as a rather surprising result of my discovery and invention, I now use the charge pump--a standard item of manufacture--to effect the overall speed control of the type of motor illustrated in FIG. 1.
Continuing with my prior art description, pumps such as that illustrated in FIG. 1 are typically controlled by a throttle valve. These throttle valves change the pressure inlet to the driving port 24. When the pressure is changed, the speed at shaft 14 varies responsive to the load.
Unfortunately, as is well known in the hydaulic arts, a power loss occurs when pump inlet pressure is throttled. Remembering that horsepower out is a function of pressure drop times flow, any throttling with an accompanying fluid flow is inevitably a power drop. The throttling effect dissipates power in the form of Joule heating of the hydraulic fluid. The heat that is generated typically must be removed by attached coolers; power is completely wasted to the extent of the controlling pressure drop.
It has been known in the past to control variable stroke motors with flyball-type governors. Unfortunately, such governors are extremely limited in the speed ranges which may be controlled. Moreover, where dynamically moving devices such as hydraulic carriages and the like are utilized, governors of the flyball variety are subjected to inertial forces. As a result, they are generally unsatisfactory in other than stationary applications.
SUMMARY OF THE INVENTION
In a positive displacement variable stroke motor, a constant speed variable power drive governor is disclosed which varies stroke instead of driving pressure and hence conserves power through reducing throttling losses. Typically, the control is used on at least one of a plurality of motors all driven from the high pressure manifold of a pressure compensated controlled pump driven by a prime mover. The particular controlled positive displacement variable stroke motor is connected at fluid intake to the high pressure manifold on the high pressure fluid side and discharges to a reservoir on the low pressure fluid side. The controlled motor also drives a small positive displacement pump--typically an in situ charge pump--and produces a discharge through a square edge orifice in an isolated hydraulic control circuit. In response to load changes, a hydraulic amplifier monitors the pressure in the hydraulic control circuit and changes the motor stroke, typically by changing tilt box angle. With decreasing hydraulic control circuit pressure responsive to increasing load, pump stroke is increased. With increasing hydraulic control circuit pressure responsive to decreasing controlled pump load, pump stroke is decreased. In either case, when the pump stroke reaches its new setting, the small positive displacement pump returns the pressure in its isolated circuit substantially back to the original pressure. A number of exemplary circuits are illustrated including various types of hydraulic amplifiers, dual motor controls, controls for use with reversible motors and an embodiment including a throttle valve in series with the controlled motor.
OBJECTS, FEATURES, AND ADVANTAGES
A primary object of this invention is to control motor stroke rather than motor pressure to thereby minimize throttling losses in a fluid motor hydraulic circuit. Typically, a controlled motor is connected to a positive displacement control pump at its output shaft. This positive displacement pump takes suction from a reservoir and discharges across a square edge orifice in a pressure isolated hydraulic circuit. The pressure between pump and orifice is passed to a hydraulic amplifier. The hydraulic amplifier changes tile box angle. Responsive to decreasing speed and increasing load, tilt box angle is moved by hydraulic connection to the amplifier to increase pump stroke responsive to decreasing back pressure. Conversely, with increasing pump speed and decreasing load, the control pump--typically an in situ charge pump--has a relatively high pressure between the pump and its metering orifice. This high pressure in turn causes the attached fluid amplifier to provide decreased pump stroke and hence decrease speed.
Upon return of the pump to a normalized speed, pressure between the control pump and orifice normalizes.
An advantage of this invention is that it saves power. Specifically, it is known that diesel engines in the range of 750 horsepower (a common prime mover utilized with hydraulic systems) consume approximately 0.4 pounds of fuel per horsepower hour. Remembering that diesel engines, their driven hydraulic pumps and the power extracting hydraulic motors are typically all sized for a maximum load condition, it can immediately be seen that operating the diesels at less than full horsepower can save fuel. For example, taking the case of two 1500 horsepower diesels and presuming that 30% of the power is saved, up to 48 gallons of fuel per hour can be saved or 1152 gallons per day.
A special result of my pump is that the system uses an in situ charge pump which is a standard item of manufacture. My control system in the entirety uses no special equipment.
My invention will admit of a number of control embodiment velocities. Accordingly, and in a first and simplest embodiment, I include the use of a hydraulic amplifier in the form of a conventional pressure compensator to amplify the control pressure between the pump and orifice to a hydraulic pressure which directly controls motor stroke.
In an alternate embodiment, I include a compensator controlling both a variable stroke hydarulic motor and a fixed stroke hydraulic motor, both these motors being operated in parallel. By the expedient of using the reversible characteristic of a variable stroke hydraulic motor, the overall motors operable on the same shaft can move from a first disposition with virtually no power output where the motors are hydraulically opposed one to another to a second and final disposition wherein the motors operate together in parallel to provide combined and additive power output.
According to another aspect of my invention, I illustrate a reversible motor control with control of piston stroke operable to not only vary motor stroke for the desired power setting, but additionally to operate other similarly situated motors in series.
An additional advantage of my control system is that the speed monitoring pump and its associated fluid circuit is pressure isolated from the driving fluid circuit of the prime mover. This being the case, the entire system is pressure independent from any prime mover pressure variations. My control will always seek to maintain constant hydraulic motor speed even though there is substantial variation in the driving pressure.
A further object of this invention is to disclose a self-braking pressure relief system for the hydraulic motor. According to this aspect of the invention, there is provided a relief valve across the discharge of the motor directly to the reservoir and around the hydraulic amplifier. Where the prime mover undergoes a sudden stop, momentum at the prime mover cannot cause pressure spiking. Instead, the fluid motor in effect pumps its momentum away as a pressure loss across the installed relief valve.
A further object of this invention is to provide my controlled motor with variable speeds. According to this aspect of the invention I only need vary the size of the controlled orifice. The controlled speed follows as a direct result of the variable orifice.
Other objects, features, and advantages of this invention will become more apparent to the reader after further referral to the remaining portion of the specification and the attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a drawing of a prior art positive displacement controlled stroke pump such as that manufactured by the Sundstrand Corporation of Ames, Iowa under the marks SUNDSTRAND HYDROTRANSMISSION, a registered trademark of the Sundstrand Corporation;
FIG. 2 is a schematic of my invention illustrating the control of a positive displacement variable stroke non-reversible motor through the hydraulic governor of my invention with the pressure of the governor controlling the position of an amplifier in the form of a hyraulic compensator;
FIG. 3 illustrates a simultaneous control of a fixed stroke hydraulic motor and a variable stroke hydraulic motor with the variable stroke hydraulic motor moving from a position of opposition to a position of being parallel to the effort of the fixed stroke motor, the control mechanisms remain substantially unchanged;
FIG. 4 is an illustration of my invention utilized to drive and control reversible hydraulic motors on a device such as a carriage;
FIG. 5 is a hydraulic circuit schematic of my invention utilizing a control motor back pressure to produce such a desirable control characteristic; and
FIG. 6 is a torque speed diagram illustrating the control characteristics of my invention.
DETAILED DESCRIPTION OF THE INVENTION
Having set forth in FIG. 1 the configuration of the motor, the schematics of FIGS. 2, 3, 4 and 5 will be sufficient to understand the operation of this invention. First, the control of various motor arrangements motor will be set forth. Finally, the speed-torque characteristics will be discussed with respect to FIG. 3.
Referring to FIG. 2, a high pressure line 14 drives a positive displacement variable stroke motor M with hydraulic discharge occuring to a discharge line 15 and thence to a return (not shown). Coaxially connected to the shaft of the motor M is a positive displacement control pump P. Pump P draws a suction from a line 16 and discharges to a line 17 across a variable orifice 18 to a reservoir 20. Provision is made at a relief valve 22 to enable overpressure to be discharged.
A hydraulic amplifier A here shown in the form of a compensator monitors the control pressure in line 17 between pump P and the variable orifice 18. Specifically, the compensator includes three spools 23, 24, 25 all connected by a common shaft 26 and biased against a spring 30 within a cylinder cavity 32.
Operation of the device may be easily understood. Assuming that the motor M comes up to speed, a control pressure will be generated between the pump P and the valve 18. This control pressure will be monitored by the amplifier A and in effect balanced against the spring constant provided by spring 30.
Upon the motor receiving an underspeed condition, the spool assembly will shift to the left, enlarged passageway 34 will communicate hydraulic fluid outflowing from the control cylinder 25. The motor will then come offstroke in the manner described with respect to FIG. 1.
Assuming that the load of motor M decreases, the motor will overspeed. Pump P will increase the pressure in line 17 and through orifice 18. With such increased pressure, biasing of the spool assembly 23, 24, 25 to the right will occur. Pressure will be communicated from line 17 through the pressure side to cylinder 25. Motor will come offstroke.
It will be seen that amplifier A serves in effect to balance the motor control responsive to the load on the motor. As will hereinafter be more fully set forth, by variation of the throttle valve 18, a speed range for the motor may be selected, which speed range is independent of the power.
Referring to FIG. 3, an alternate embodiment of my invention is illustrated. Two motors M 1 , M 2 are connected to a common shaft. Motor M 1 is a positive displacement variable motor. Motor M 2 is a positive displacement fixed stroke motor. Understood in the terms of FIG. 1, the tilt box 20 is preset in motor M 2 . It remains set to a constant angle.
Motor M 1 has a variable tilt box. This tilt box varies from a first position where it is in opposition to motor M 2 to a second position in sympathy with motor M 2 .
Operation of this speed control is analogous to that shown in FIG. 2. Broadly, an inlet pressure line 14 drives motor M 1 while line 14' drives motor M 2 . Discharge occurs through lines 15, 15' to a reservoir not shown. Pump P takes a suction 16, discharges through check valve 17a to variable throttle 18, finally to a reservoir 20. A relief valve 22 is provided to bypass pressures in the event of motor overspeed. Operation is precisely the same as that previously illustrated.
For a condition of increased load, pump P slows down. In slowing down, the pressure in line 17 to orifice 18 drops. Upon experiencing pressure drop, the spool shifts to the left from the bias of spring 30 within cylinder 32 and thereby allows oil to escape from control cylinder 25 to reservoir 20. Motor M 1 goes on stroke.
Considering the case whereby motors running in parallel overspeed to a decrease in load, the pressure between pump P and throttle valve 18 rises. Upon such increase in pressure, the spool assembly 23, 24, 25 shifts to the right. With such a shift, pressure from the discharge line 17 through line 17a communicates to enlarged portion 34 of the compensator with the pressure being communicated to control cylinder 25. Motor M 1 comes offstroke.
It will be appreciated that motor M 1 may in effect have a reversible drive. Thus the motor can go from a position fully in opposition to motor M 2 to a position fully in sympathy with motor M 2 .
Referring to FIG. 4, yet an alternate embodiment of this invention is illustrated. In this embodiment, three reversible motors M 1 , M 2 , M 3 are all shown run of of a common inlet 40, with common discharge to a discharge line 42. These particular motors are run in a reversible mode and will be set forth with respect to motor M 1 . Once the operation of motor M 1 is understood, the coupling and uncoupling of motors M 2 , M 3 via the hydraulic clutch mechanism 44 can then be set forth.
Typically, a control pressure in the range of 300-500 psi is provided to an inlet valve 45. Inlet valve 45 is a three-way valve biased by a throw rod 46 against opposing center biasing spring forces. Assuming that valve 46 is thrown to the left position, it will be immediately seen that line 48 is communicated to a source of pressure and line 49 communicated to a reservoir. Assuming that the motor is in the stop position, fluid passage will occur through check valve 50 in line 51. Such fluid flow will proceed through line 50 to line 52 wherein, and assuming motor M 1 is in the stop position, the pump P will act as a closed valve. The fluid pressure from the control circuit in line 45 will thence see its way to one of two opposed control cylinders 25 and motor M 1 will go on stroke in a first condition.
Once the motor is on stroke in the desired condition, fluid will pass pump P from line 52 to line 53. At line 53, the passed fluid will see its way through a pressure relief valve V 1 . Typically, relief valve V 1 will be biased by a lines 55, 56 to a position where some relief of the control pressure from pump P occurs. Once relief valve V 1 opens, fluid will flow through line 49 down to the reservoir.
Thus, dependent upon the position which handle 46 is in, there will occur a control of the motor M 1 .
In the particular circuit of FIG. 4, this circuitry has been designed by me for the control of a movable carriage. This being the case, it will be noticed that a special valve 60 is actuated to release a brake 61 to line 62 containing valve 63. Thus in the absence of hydraulic pressure, brake 61 engages preventing carriage movement altogether.
Assuming movement in the opposite direction is desired, handle 46 is shifted fully to the right. In this position, line 49 gets communicated to a source of pressure with pressure passing through conduit 71 and check valve 72 to bring cylinder 26 on stroke. When motion of the motor commences, pump P causes pressure to be exerted on line 52. Dependent upon the pressure in line 71, a lines 75, 76 will cause valve V 1 to move to the slightly open position, pressure will be relieved on line 52 through to reservoir 20. There will result an equilibrium in the system which equilibrium will cause a steady state movement of motor M 1 .
It will be noticed that valve 46 includes in portions of the throttle therein illustrated, the variable throttle mechanisms 74, 75. These respective throttle mechanisms enable motor speed to be controlled.
Referring to control lines 52, 53 of the pressure drop generated thereacross, it can be seen that by the utilization of clutch mechanism 44, respective motor M 2 with pump P 2 and motor M 3 with pump P 3 can be switched on and off the line. In each of these cases, the function of the system is precisely analogous.
Having set forth these two embodiments of my invention, attention may now be directed to FIG. 5.
In FIG. 5 I have caused to be added to the control mechanism an amplifier of the configuration previously illustrated in my U.S. Pat. No. 3,807,443, issued Apr. 30, 1974. I incorporate that patent by reference. The information may be summarized as follows:
A pressure regulated constant flow valve has a fixed orifice and a regulated orifice in series, the regulated orifice maintaining a constant pressure drop across the fixed orifice. To maintain the pressure regulation effective for either direction of flow through the valve, a shuttle valve shifts when the direction of flow is reversed and reverses the connections of the regulator with the upstream and downstream sides of the fixed orifice.
A typical claim is as follows:
1. A bi-directional, pressure compensated, flow control valve comprising a fixed orifice and a regulated orifice in series, orifice regulating means having opposed opening and closing areas, a shuttle valve connected to the regulating means and shiftable to connect the closing area with the upstream side of the fixed orifice, and to connect the opening area with the downstream side thereof for each direction of flow through the valve.
Reference is made to the mechanism illustrated in FIG. 5 as amplifier A as being the incorporated portion of my previously issued U.S. Patent, the illustrations here and there being substantially identical.
The amplifier A which I incorporate in my embodiment of FIG. 5 may also be found fully described in the Sperry-Vickers Industrial Hydraulic Manual, 1st Ed. (1970), published by the Sperry-Rand Corp. of Troy, Mich. An explanation of this valve may be found at page 9-12 at FIG. 9-12 (and text relating thereto), the only difference being that the control pressure for the amplifier therein illustrated is taken from the inlet to the fluid motor instead of the pressure generated between the positive displacement pump P and orifice.
Referring to FIG. 5, pump P has an output of hydraulic fluid to a manifold 140. Motor M is a typical variable stroke positive displacement pump utilized in such installations. Motor M receives hydraulic fluid on its high pressure side 141 from a branch of manifold 140 and discharges fluid to its low pressure side 142 through a fluid amplifier A to a reservoir R through discharge line 143. Reservoir R in turn provides the suction side of pump P with fluid through a return line 144 so that the prime mover of pump P can provide motor force to the manifold 140 and again to the high pressure line 141 into motor M.
Motor M at its charge pump 130 has an independent hydraulic circuit. Charge pump 130 has an inlet line 145 and a discharge 146. Discharge 46 discharges through a variable square edge orifice 147 to a reservoir discharge line 148. It is the pressure maintained between the discharge of charge pump 130 and line 146 to the variable square edge orifice 147 which is the control pressure to fluid amplifier A.
Fluid amplifier A comprises paired spools 150, 151 connected by a shaft 152 to a hydraulic piston 154. Piston 154 is spring biased by a spring 155. Piston 154 fits within a large piston cylinder 156 while a reduced piston cylinder 157 with an enlarged inlet opening 158 provides for passage of hydraulic fluid. A narrow chamber 159 mating piston 150 is illustrated to drive spool 150 into and out of a partially occluding position within chamber 158.
In operation, the fluid discharged from motor M passes through conduit 142 into the enlarged portion of cylinder 158. From enlarged portion 158, the fluid passes between cylinder 150 and shaft 152 to discharge line 143 (this latter line being schematically shown). Fluid passes from discharge line 143 to reservoir R.
Compared to prior art apparatus, it will be noticed that the throttling of this invention is downstream. It is not contained upstream of the motor M. Further, fluid amplifier A is given a setting so that piston 150 interior of chamber 158 and cylindrical chamber 157 has a minimal pressure drop. Preferably, the pressure drop is of the order of 200 pounds with the overall pressure differential of the system being in the range of 3000 pounds. Thus any throttling which the fluid amplifier A gives to the entirety of the system is minimal.
It will be noticed that the pressure of outflow between outflow 146 of charge pump 130 and the variable square edge orifice 147 is communicated to fluid amplifier A at two apertures. First, a static pressure goes to cylindrical portion 159 where it acts on the end of cylinder 150. Secondly, a pressure line 146a goes to cylinder 156 where it acts against cylinder 154.
Counteracting this hydraulic pressure, there is a line 160 which communicates to chamber 156 on the opposite side of piston 154. This pressure from the low pressure or discharge side of the variable square edge orifice 147 together with the set spring pressure 155 selects the medial and relatively low back pressure position of cylinder 150 of the amplifier A.
Having described the configuration of the amplifier, the operation of the amplifier will now be set forth.
Assume that motor M picks up an increased load. When this happens, its shaft speed will typically drop. Upon dropping of the shaft speed, the pressure in line 146 between the variable square edge orifice 147 and the charge pump 130 will drop. When this pressure drops, the fluid pressure in chambers 159 and 156 will likewise decrease. Consequently, bias of the fluid amplifier will be to have spring 155 move cylinders 150, 151, 152 and 154 to the left. Back pressure on the pump will drop.
The immediate effect of the drop and back pressure on the pump will be two-fold. First, motor M will see less back pressure between itself and reservoir R. This being the case, more power will be immediately produced. As will hereinafter be set forth, with a pressure-regulated pump P, this has a beneficial time constant effect. Secondly, because the back pressure is reduced on the pump, chamber 158 will see less pressure. This will be because of two distinct effects. The first is that because piston 150 slides further into and penetrates chamber 159 and at the same time opens the opening between chambers 157 and 158, the natural and unobstructed fluid flow between the two chambers will reduce the back pressure. The second is that because the constriction between the chambers 158 and 157 is opened, any Bernoulli effect present will be reduced. Such effects are important in considering the closure of an apparatus such as amplifier A.
Now let us consider the overspeed of motor M due to a decreased load. when such overspeed occurs, the pressure in line 146 rises. By the same considerations previously discussed, the fluid pressure in chambers 159 and 156 will increase. Biasing movement of the cylinders 150, 151, 152 and 154 will all occur to the right.
As an immediate effect in the overspeed condition, motor M will see increased back pressure. Responsive to increased back pressure, the motor will turn at a slower rate because it has less power in the pressure drop between manifold 140 and the reservoir R. The back pressure of the motor in chamber 158 will rise for two reasons. The first is that the constriction which cylinder 150 produces between chambers 158 and 157 will go to a smaller area. With more of a restriction, back pressure in chamber 158 naturally will rise. The second is that the Bernoulli effect which draws piston 150 towards chamber of the sidewall 157 will likewise increase. Thus the movement of the piston assembly 154 against the spring 155 will be present.
Having set forth the immediate effects produced by fluid amplifier A, attention will now be directed to how the back pressure on the pump controls the angle of the tilt box plate 120 to motor M and varies the stroke responsive to that back pressure.
Broadly, chamber 158 connects through a conduit 163 to cylinder 126. Typical connection is made through a conduit including opposed check valves 164, 165 and a throttling bypass 167 with paired throttle valves 168, 169 contained therein. These throttle and/or needle valves 168, 169 provide an adjustable time constant to movement of the tilt box 120 as actuated by cylinder 126 on spring bias cylinder 125. Remembering the provision previously discussed about the function of amplifier A, the operation of the circuit to effect change in motor stroke upon first an underspead condition and second an overspeed condition can now be set forth.
Regarding an underspeed condition, it will be apparent that motor M picks up increased load. When increased load was first acquired, it will be remembered that the back pressure in chamber 158 decreased. Such decreasing back pressure through conduit 163 to cylinder 126 (and through the needle valves 168, 169) will reduce the pressure in piston 126. Consequently the spring bias of piston 125 will cause the pump M to undertake additional stroke. When the pump undertakes additional stroke, more fluid will pass through the pump, further power will be delivered and charge pump 130 will increase in its output. Once the pump 130 increases in its output, the pressure in conduit 146 and adjustable orifice 47 will return to normal. At this point, the fluid amplifier will return to its normal position, leaving the tilt box 120 in its position of increased stroke.
Responsive to an overspeed condition, where motor M experiences less load, it will be remembered that the back pressure in chamber 158 increased. Upon increase in back pressure, hydraulic pressure on cylinder 126 will increase. The tilt of box 120 will become less and the resultant piston stroke will be reduced. As the piston stroke is reduced, motor M will decrease or return to a normal speed range. Returning to the normal speed range will cause charge pump 130 to put out a reduced pressure on line 146. With a reduced pressure on line 146, amplifier A will return to the normal position. Equilibrium will be restored to the system with the motor M in a position of decreased stroke.
Having explained my invention thus far, it will be apparent that by varying stroke instead of pressure drop, I vastly reduce throttling losses within the system. Instead, my motors M only call upon that amount of hydraulic power out from pump P as is required to run to my manifold 140.
Before I proceed to a speed torque explanation of FIG. 6, several points should be made.
First, I have provision for that contingency wherein motor M has a high inertial load on it, and pump P suddenly shuts down. Upon such a condition, it will be seen that amplifier A could restrict all fluid flow through the system. To prevent such a result, I have a relief valve 170 which enables a throttling fluid flow between conduit 142 and reservoir R. This conduit serves the dual function of preventing an over-pressured spike on the discharge side of the pump as well as providing a throttling loss to dissipate hydraulic energy interior of motor M.
Secondly, I provide for a control to my variable square edge orifice 147. Specifically, a standard variable pressure hydraulic control C actuated by a lever 172 actuates through a diaphragm 174 to control the position of the orifice 147. By varying the position of the orifice 147, the control characteristics of the motor can be varied as will hereinafter be described with respect to FIG. 6.
Additionally, to prevent system overspeed in the event that motor M suddenly loses all power, I provide an overspeed control orifice 176. This orifice functions in series with the variable orifice 147 so that charge pump 130 will always see back pressure, especially when during overspeed charge pump 130 on an uninhibited basis discharges through a fully open square edge orifice 147.
Having set forth the general operating conditions of my invention, attention will now be given to the configuration of a prior art pressure compensated control pump power source. This power source will be described so that a serendipitous result of my invention in conjunction with such power sources can be understood.
Typically, a pump P is driven by a prime mover (not shown) such as a diesel engine. This pump P has the same configuration as that previously illustrated in FIG. 1, with the only difference being that the shaft 114 is driven by the motor instead of providing a driving motive force.
The output of the pump on the high pressure side is communicated to a piston and spool assembly, including a spring biased piston portion 180 and attached spool assemblies 181, 182, 183, all of these spool assemblies being connected by a common shaft 184. There is an enlarged chamber 186 between spool assemblies 181 and 183, which enlarged chamber 184 is normally obstructed by spool assembly 182. The outflow from this chamber passes along conduit 187 to a control cylinder 190. Control cylinder 190 varies the tilt box 192 of pump P against a spring biased cylinder 194 in the manner that has previously been illustrated.
Operation of the device is well understood in the prior art and will be briefly set forth here only for clarity of understanding. Specifically, where the pressure at manifold 140 drops (indicating that all the motors M are consuming more power) the pressure against the spool assemblies 181, 182, 183 will likewise drop. Spool 182 will move to the right out of an obstructing position to chamber 186. The spring bias of piston 194 will act against piston 190 with a discharge to a reservoir R 2 occurring until pump stroke P increases. When the pump stroke P increases, more flow will be added to the system.
Where there is a pressure increase, the effect will be the opposite. Specifically, the spool assembly 181, 182, 183 will move to the left with spool 182 no longer obstructing the path between a conduit 193 and conduit 187. Higher pressure will be communicated to cylinder 190 with the tilt box 192 calling for less pump stroke. With less pump stroke, the flow will decrease.
With such systems throttle valves A and B can cause a hunting; the explanation for this hunting is relatively simple.
Typically, the throttle valves dissipate the power required between a full load operation at motor M and that power which motor M is in fact using. That is where motor M is running at a relatively low output torque, great amounts of energy are consumed in throttling losses.
Assuming that more power is suddenly called for, a throttle valve to motor M would suddenly open. At the same time, motor M will increase its stroke. Upon such sudden opening and increased stroke, the pressure in conduit 140 would drop even more. The spool assembly controlling the pump P would call for additional stroke. Pump P typically would be called upon to overcompensate. There could result a hunting which, depending upon the time constants involved in the respective controls, could be even unstably resonant in overall effect.
It will be remembered, however, that with my present control, the back pressure on motor M immediately drops responsive to an underspeed condition. Accordingly, motor M sees a greater pressure drop when experiencing greater load. Seeing a great pressure drop, it has greater hyraulic energy to consume responsive to that pressure drop. Thus in my present invention, the upstream pressure at inlet 141 from manifold 140 will remain substantially unchanged immediately responsive to increased load at motor M.
A further aspect of this invention will be appreciated by those skilled in the art. Specifically, it will be seen that the hydraulic circuit between the charge pump 130 and the orifice 147 is independent of any pressure in manifold 140 produced by pump P. This being the case, motor M will always seek to maintain its desired speed.
Having set forth the operation of the circuit, the torque speed characteristics can now be explained. Referring to FIG. 6, a hypothetical torque speed characteristic of the control drive is shown. Specifically, speed is plotted on the abscissa with torque being plotted on the ordinate. A maximum torque placed by the machine will occur at zero speed at point 100.
Assuming that the motor is operating at full power and full speed, fluid amplifier A will be in the full open position with the tilt box set at a maximum. This will occur at point 102 of the torque speed curve. Motor rpm is labeled with the set speed here being illustrated as 1800 rpm's. For convenience of size, the torque speed curve is broken off to illustrate on an expanded basis the range between 1800 and 1836 rpm's, the total speed range of the orifice setting set forth here.
Responsive to decreasing load, amplifier A will close, causing a back pressure. This back pressure will reduce the torque along a line of essentially constant slope to a point 103.
When amplifier A responsive to the increased speed of the motor has reached its adjusted and biased position, movement of tilt box 120 will occur to change piston stroke. Such movement will occur from points 103 to 104 responsive to decreasing load. This movement will occur until the tilt box 120 is in the minimum displacement condition.
When the minimum displacement condition is reached, only movement of amplifier will occur. Such movement will occur until the back pressure is equal to the pressure in the manifold 140, and essentially no turning of the motor occurs. This maximum speed at essentially zero power output of the motor is illustrated at point 105.
It will be appreciated that line 102-103 and line 104-105 on the enclosed graph are essentially exaggerated. They are presented here only so that understanding may be increased of the fluid amplifier A on the torque speed curve. Moreover, the particular speeds here chosen are exemplary.
Assuming that a motor runs at about 50% of the power rating, the motor would run at a total speed of 1818 rpm at a half power rating. This half power rating is illustrated by point 106 on the curve between points 103 and 104. If the motor had been run with an upstream throttling valve, that area of the curve above line 110 would represent the power loss that a motor would have.
It will be noted that points 102, 103, 106, 104 and 105 all include what might be referred to as a reverse S-shaped curve. It will be appreciated by those skilled in the art that the variation of the orifice at 147 will in effect shift the reverse S-shaped curve left to right depending upon whether the variable square edge orifice is open or closed. Where the orifice is closed, shifting of the reverse S-shaped curve will occur to the left of the diagram in FIG. 6. Where the variable square edge orifice 147 is opened, shifting will occur to the right.
It should be understood that in all cases I illustrate here a square edged orifice which is definitely preferred. As it is known that square edged orifices vary their pressure drop with the approximate square of the fluid flow across them, I find that square edged orifices are a particularly preferred control orifice to use with my invention. These orifices when used provide a relatively large variation in pressure for relatively small variations of flow. Improved control results.
In summary, it can be seen that the present invention provides a surprisingly efficient and simple control system for hydraulic motors. While the above represents a full and complete disclosure of the present invention, alternate embodiments, equivalents, and the like may be employed. For example, while variable stroke motors are disclosed, other variable displacement devices may be used. Therefore, the foregoing description should not be construed as limiting the scope of the present invention which is defined by the appended claims.
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In a positive displacement variable stroke motor, a constant speed variable power drive governor is disclosed which varies stroke instead of driving pressure and hence conserves power through reducing throttling losses. Typically, the control is used on at least one of a plurality of motors all driven from the high pressure manifold of a pressure compensated controlled pump driven by a prime mover. The particular controlled positive displacement variable stroke motor is connected at fluid intake to the high pressure manifold on the high pressure fluid side and discharges to a reservoir on the low pressure fluid side. The controlled motor also drives a small positive displacement pump--typically an in situ charge pump--and produces a discharge through a square edge orifice in an insolated hydraulic control circuit. In response to load changes, a hydraulic amplifier monitors the pressure in the hydraulic control circuit and changes the motor stroke, typically by changing tilt box angle. With decreasing hydraulic control circuit pressure responsive to increasing load, pump stroke is increased. With increasing hydraulic control circuit pressure responsive to decreasing controlled pump load, pump stroke is decreased. In either case, when the pump stroke reaches its new setting, the small positive displacement pump returns the pressure in its isolated circuit substantially back to the original pressure. A number of exemplary circuits are illustrated including various types of hydraulic amplifiers, dual motor controls, controls for use with reversible motors and an embodiment including a throttle valve in series with the controlled motor.
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BACKGROUND OF THE INVENTION
This invention relates to sheet feeders for feeding sheets, such as paper towels used for toilets, kitchens, etc. and polyethylene bags in super-markets.
Most paper towel feeders used today dispense paper towels which are precut to a uniform length.
In such a sheet feeder, however, paper towels are accommodated in a folded state. The quantity of paper towels that are accommodated is small, and frequent replenishment required. Because special cut paper towels are used, the cost is high.
In view of these problems, a roll paper towel feeder is proposed, in which an long paper sheet wound in the form of a roll is cut to a suitable length whenever it is fed for use.
This paper feeder has features such that the quantity of paper that can be accommodated can increase greatly compared to the case where folded paper is used, that the replenishment with paper may be made by a reduced number of times, and that the paper that is used is inexpensive in cost. However, it is difficult to cut the supplied paper to a uniform length. One possibility is to provide precut incisions at, for example, every several tens of centimeters. By so doing, however, paper may, in many cases, be pulled irrespective of the incisions positions. This leads to the use of more paper than a prescribed quantity, thus resulting in early consumption of paper and leading to increased cost.
To solve this problem, one might provide a load to make it difficult to pull the paper. Paper towels, however, are usually handled with a wet hand, and therefore, it is likely that a leading end portion of the towel will be broken apart from the rest of the towel.
SUMMARY OF THE INVENTION
It is an object of the invention is to provide a sheet feeder, which can feed sheets having a uniform length.
A further object of the invention is to provide a sheet feeder, which permits avoiding the waste of sheets and consumption saving thereof.
A further object of the invention is to provide a sheet feeder, which has satisfactory operation control property of sheet pulling.
The above objects of the invention are achieved by a sheet feeder for feeding a long sheet wound in the form of a roll as cut sheets having a predetermined length, which
a housing; and
a pull length regulating means being attached to the housing, for stopping the running of the long sheet when the sheet has been pulled by a predetermined length.
The pull length regulating means may comprises:
a rotor brought into contact with the long sheet at a position in a predetermined course of said long sheet running and rotated based on the action of the friction between the long sheet and the rotor; and
a rotation regulating means for regulating the rotation of the rotor.
Preferably, the rotor rests on the running long sheet such that its weight acts on the long sheet.
Preferably, the rotation regulating means comprises:
a movable member disposed on an end of the rotor;
a hook portion provided on said movable member; and
a hookable portion provided on the rotor in correspondence to the hook portion.
Preferably, the hook portion is a projection, while the hookable portion is a recess capable of being engaged by the projection.
According to another aspect of the invention, the sheet feeder further comprises:
a biasing means serving, when the rotor is moved upward by a tension acting on the long sheet, to cause displacement of the movable member by a predetermined angle in the opposite direction to the direction of rotation of the rotor lest the hook should hook the hookable portion;
after substantially one rotation of the rotor with the running of said long sheet, the hook portion having been displaced by the biasing means hooks the hookable portion to stop the rotation of the rotor.
Preferably, the rotor is a cylindrical member having an inner diameter of r 1 and the shaft has an outer diameter of r 2 (r 1 >r 2 ), the shaft; being inserted in a center hole of the cylindrical member.
Preferably the movable member is a cylindrical member having an inner diameter of r 3 ; and
the level of the axis of the cylindrical member with the inner diameter of r 3 is set to be higher than the level of the axis of the cylindrical member with the inner diameter of r 1 .
Preferably, the movable member is a cylindrical member having an inner diameter of r 3 ; and
a shaft having an outer diameter of r 2 (r 3 >r 2 ) being inserted in the central hole of said cylindrical member, the level of the axis of the cylindrical member with the inner diameter of r 3 being set to be higher than the level of the axis of the shaft with the inner diameter of r 2 .
Preferably, the movable member is a cylindrical member having an inner diameter of r 3 ;
a shaft having an outer diameter r 2 (r 3 >r 2 ) being inserted in the central hole of the cylindrical member,
a spacer being provided between the cylindrical member and the shaft, the level of the axis of the cylindrical member with the inner diameter of r 3 being set to be higher than the level of the axis of the shaft.
Preferably, the spacer provided between the cylindrical member and the shaft is a spring member.
Preferably, the movable member has a convexity formed on the outer side;
the convexity being provided such that it is loosely fitted with a groove such as to define a range of displacement of the movable member.
According to another aspect of the invention, the sheet feeder suitably further comprises a braking means for braking the sheet to prevent idling thereof by a pull force applied to the long sheet. Particularly, the braking means is constituted by pair rollers for pinching the long sheet there between to thereby apply a braking force to the long sheet.
According to the invention, the sheet feeder suitably further comprises a guide roller disposed between the rotor and a pull outlet and at a level higher than the level of the axis of the rotor.
Preferably, a rubber member is provided on the outer periphery of the rotor.
The sheet feeder according to the invention has pull length regulating means such that sheets having a uniform length can be supplied at all times, there being no possibility of pull of sheet beyond a prescribed length. Thus, it is possible to effectively prevent the waste of sheet and permit great saving thereof.
Besides, since the sheet is adapted to be stopped automatically when it is pulled by a predetermined length, there is no need of holding the sheet under great load. Thus, the sheet can be pulled without need of great force, and it is not broken apart even by pulling it with a wet hand. It is thus possible to readily pull the sheet.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other objects, features and advantages of the invention will become more apparent when the detailed description of the preferred embodiment of the invention is read with reference to the accompanying drawings, in which:
FIG. 1 is a perspective view showing substantially the internal structure of a paper feeder (i.e., sheet feeder);
FIG. 2 is a perspective view showing a pull length regulation mechanism;
FIG. 3 is a perspective view showing a relation between a groove and a convexity;
FIG. 4 is a side view showing the operating status of the system;
FIG. 5 is a side view showing another operating status of the system;
FIG. 6 is a plan view showing an operating status of the system;
FIG. 7 is a plan view showing another operating status of the system; and
FIG. 8 is a side view showing a further operating status of the system.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawings wherein like numerals indicate like elements, there is shown in FIGS. 1 to 8 show an embodiment of paper feeder (i.e., sheet feeder) according to the present invention. As best shown in FIG. 1, a long roll of paper F is accommodated on a feed roller 1 in a case A. The paper F is passed between guide rollers 2 and 3 which face one another, causing the paper F to change in direction from the horizontal to vertical. Subsequently, the paper F is fed to a pull length regulation mechanism 5 described below.
After passing through the pull length regulation mechanisms, the direct of the paper F is changed by the guide roller 4 from the vertical to the horizontal. The guide roller 4 is provided at a level above the level of the axis of rotation of a cylindrical member in the pull length regulation mechanisms, and the paper F is thus pulled to the outside from a level position above the axis of rotation of the cylindrical member.
The guide rollers 2 and 3 are provided such that they pinch the paper F. The pinching force is adjusted to provide a predetermined braking force to the paper F. As shown in FIG. 2, the pull length regulation mechanism 5 includes a cylindrical shaft 6 (having an outer diameter of r2), a stationary ring 7 having an inner diameter r3 slightly greater than the outer diameter r2 of the shaft 6, a movable ring 8 (movable member) having an inner diameter of r3, and a cylindrical member 9 (rotor) having an inner diameter r1 (r1=r3) and rotatable about the shaft 6.
The stationary and movable rings 7 and 8, respectively, have outer peripheries which are smooth and less subject to friction. The outer periphery of the cylindrical member 9, on the other hand, is provided circumferentially with a rubber member 9a having a large coefficient of friction to prevent slippage with respect to the paper F.
The shaft 6 and stationary ring 7 are secured to the case A. A spacer 10, for example a leaf spring is provided between the movable ring 8 and shaft 6, for biasing the axis of the movable ring 8 to a position above the axis of the shaft 6. The movable ring 8 is rotatable about the shaft 6 by a slight angle. The movable ring 8 has a projection 12. As shown in FIG. 3, the projection 12 is loosely fitted in a long groove 11 provided in the case A. The movable ring 8 can be revolved in the range defined by groove 11.
As shown in FIG. 2, the cylindrical member 9 is usually in a position slightly lower than that of the stationary and movable rings 7 and 8, respectively.
A projection (hook portion) 13, having a width of l 1 (FIG. 6) is provided on the inner end of the movable ring 8. The cylindrical member 9 is formed with a notch 14 (hookable portion) having a width l 2 (l 2 >l 1 ).
A spring (biasing means) 15 is stretched between the case A and the projection 12. The movable ring 8 is biased by the spring 15 such to rotate in a direction opposite to the direction of rotation of the cylindrical member 9, i.e., toward a paper outlet. Correspondingly, the projection 13 is tilted slightly from the overhead position toward the paper outlet.
In the system having the above structure, before a tensive force is applied to the paper F, the cylindrical member 9 and moveable ring 8 are in the position illustrated in FIG. 4. The projection 13 (at location x) and the notch 14 are not aligned. Additionally, the cylindrical member 9 is in a position lower than the stationary and movable rings 7 and 8 when the paper is pulled taut, the cylinder and member 9 are raised by the paper F being to a level shown by the phantom line. As a result, the cylindrical member 9 is brought to be substantially at the same level as the stationary and movable rings 7 and 8.
In this state, the projection 13 of the movable ring 8 moves to a position abutting the outer surface of the cylindrical member 9 of the notch 14 of the cylindrical member 9, i.e., on the side of the paper outlet (as shown at point X). Thus, the projection 13 is not located in the notch 14 when the cylindrical member 9 is initially raised by the paper F.
When the paper F is pulled, the cylindrical member 9 is rotated clockwise as viewed in FIG. 1 with its outer surface in contact with the projection 13 of the movable ring 8.
When the paper F has been pulled by a length L corresponding to the circumference of the cylindrical member 9, as shown in FIG. 5, the cylindrical member 9 has completed substantially one rotation. At this time, the notch 14 reaches the position of the projection 13. Consequently, the projection 13 moves into the notch 14, as shown in FIG. 6 as the paper F is pulled further, the cylindrical member 9 rotates relative to the ring 8 until the projection 13 initially engages the opposite end of the notch 14. Thereafter, the cylindrical member 9 and the ring 8 move as a unit and the movable ring 8 is rotated slightly against the elasticity of the spring 15. Subsequently, the projection 12 is brought into contact with the end face of the groove 11, thus stopping rotation of the movable ring 8. As a result as shown in FIG. 7, the cylindrical member 9 can no longer rotate with the projection 13 in contact with the other end face of the notch 14.
Now, the paper F can not be pulled further. In this state, the paper F can be cut by applying it to the cutter provided at the outlet of case A and pulling it with a force applied thereto.
As a result, it is possible to obtain paper towels cut to a uniform length.
If paper with incisions is used, there is no need of providing an outlet cutter. That is, by strongly pulling the paper F after the paper F has become incapable of being pulled further, the pulled part of paper is cut apart at the incisions.
When the paper F is cut apart, the tension in the paper is released. As a result, the cylindrical member 9, as shown in FIG. 8, falls under the force of gravity from the position shown by phantom line to its initial position and the projection no longer engages notch 14.
Since the system is constructed such that the cylindrical member 9 is moved not in the vertical direction but in the horizontal direction, the cylindrical member 9 may be biased by a spring in the horizontal direction. By so doing, it is possible to obtain an operation similar to that described above.
After the paper F has been cut and the cylindrical member 9 returned to its lower position, the projection 13 of the movable ring 8 is pulled back to the initial position (i.e., point X) by the tension of the spring so that it is no longer aligned with the notch 14. Thus, when the paper F is subsequently pulled, the cylindrical member 9 is freely rotated without engagement of the projection 13 of the movable ring 8 in the notch 14. Thus, it is possible to again pull a length of paper F corresponding to one rotation of the cylindrical member 9.
As has been described above, with the above embodiment of the paper feeder described it is possible to pull the paper by a uniform length.
Further, the operation of the device is simple and paper is saved.
Furthermore, its structure is simple and comprises a small number of parts, so that it is less subject to troubles.
Further more, it is easy to replenish the paper.
Further more, the paper feeder can be manufactured at low cost and thus can be provided inexpensively.
While in the above description the sheet feeder is a paper towel feeder to be installed in a toilet, the invention is applicable to any other paper feeder. For example, the invention is applicable to a kitchen towel feeder used in the kitchen or to the supply of polyethylene bags consumed in supermarkets.
Further, the invention can be utilized as facsimile or printing sheet feeders. In these cases, a pull length control using complicated mechanisms controlled by a computer is unnecessary, thus permitting great simplification of the system.
According to the invention, it is possible to feed sheets having a uniform length, avoid waste of the sheet and permit ready pulling of the sheet.
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A sheet feeder for feeding a long sheet wound in the form of a roll as cut sheets having a predetermined length, comprises a housing and a pull length regulator being attached to the housing, for stopping the running of the long sheet when the sheet has been pulled by a predetermined length.
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BACKGROUND OF THE INVENTION
The embodiments herein relate to gear systems and, more particularly, to harmonic drive gear systems, as well as a method of assembling such systems.
Aircraft typically include flight control surfaces on aircraft wing structures that are moved and positioned in order to alter the lift characteristics of the wing structures. Actuators are coupled to the flight control surfaces and control and guide the movement of the flight control surfaces between positions. Generally, there are two types of actuators used in aircraft: linear actuators and rotary actuators. Conventionally, a rotary actuator uses an epicyclic-type reduction gear drive, commonly referred to as a planetary gear drive, to step down high speed rotation imputed by an electric drive motor. It is also common for a rotary actuator to use a planetary gear drive with multiple stages (multiple sets of planet gears) to increase the reduction ratio and torque-to-weight ratio of the planetary gear drive. While incorporating multiple stages into the planetary gear drive increases the reduction ratio and torque-to-weight ratio of the planetary gear drive, it also undesirably increases the size, weight, and complexity of the planetary gear drive.
Presently, the construction of aircraft wings is moving toward a thin-winged design, where the overall thickness of the wings is decreased from previous designs. Because the thickness of the wings is being decreased, it is becoming increasingly difficult to fit a conventional rotary actuator with a planetary gear drive within the cross-section of the wings, especially when the planetary gear drive incorporates multiple stages. The diameter of the planetary gear drive can be decreased in order to fit it within the reduced wing cross-sectional area, however, the size of the teeth must also be decreased in order to maintain the high reduction ratio. Reducing the size of the teeth is undesirable because it lowers the torque-to-weight ratio of the planetary gear drive while also increasing the manufacturing tolerances and cost of the planetary gear drive.
BRIEF DESCRIPTION OF THE INVENTION
According to one embodiment, a harmonic drive includes a flexible gear. Also included is a ring gear that meshes with the flexible gear. Further included is a rotor. Yet further included is a wave generator sleeve directly fitted over an outer surface of the rotor, wherein the wave generator sleeve is disposed radially within the flexible gear. Also included is a bearing assembly disposed between the wave generator sleeve and the flexible gear, wherein the wave generator rotates the flexible gear as the wave generator sleeve is rotated by the rotor.
According to another embodiment, a method of assembling a harmonic drive is provided. The method includes positioning a wave generator sleeve radially within a flexible gear and a bearing assembly, the flexible gear comprising radially-outward-extending teeth. The method also includes positioning a ring gear around a portion of the flexible gear such that radially-inward-extending teeth of the ring gear mesh with the radially-outward-extending teeth of the flexible gear. The method further includes directly fitting the wave generator sleeve to an outer diameter of a rotor configured to rotate the wave generator and the flexible gear.
BRIEF DESCRIPTION OF THE DRAWINGS
The subject matter which is regarded as the invention is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:
FIG. 1 is an end view of the harmonic drive assembly;
FIG. 2 is an end view of the harmonic drive assembly according to section A of FIG. 1 ; and
FIG. 3 is a cross-sectional view of the harmonic drive assembly according to line A-A of FIG. 1 .
DETAILED DESCRIPTION OF THE INVENTION
Referring to FIGS. 1-3 , a schematic diagram illustrates a harmonic drive assembly 10 . As shown, an input 12 , an output 14 , and a ground 18 are connected to the harmonic drive assembly 10 . In addition, more than one output can come out of harmonic drive assembly 10 . The harmonic drive assembly 10 also includes a first flexible gear 20 , a second flexible gear 22 , a ring gear 24 , and a wave generator sleeve 30 . An embedded stator assembly 60 is disposed radially inwardly of the input (also referred to herein as a rotor) 12 and is configured to cause rotation of the input 12 . The harmonic drive assembly 10 can further include other components and features not specifically shown or discussed.
The second flexible gear 22 is larger in diameter than the first flexible gear 20 and is coaxial with the first flexible gear 20 . The first flexible gear 20 and the second flexible gear 22 are connected or integrated such that the first flexible gear 20 and the second flexible gear 22 may rotate together. The wave generator sleeve 30 is disposed radially inwardly of the first flexible gear 20 and the second flexible gear 22 and engages both the first flexible gear 20 and the second flexible gear 22 , directly or indirectly. The wave generator sleeve 30 typically includes an elliptical or otherwise noncircular geometry, such as the tri-lobular geometry illustrated.
The wave generator sleeve 30 is directly fitted to the input 12 . The input 12 can be an output shaft (referred to herein as a “rotor”) of an electric drive motor, a hydraulic rotary drive, or other suitable torque source, and rotates the wave generator sleeve 30 . The wave generator sleeve 30 is directly fitted to an outer surface 52 of the input 12 via any suitable process that establishes a tight, fitting securement between the wave generator sleeve 30 and the input 12 . In some embodiments, the wave generator sleeve 30 is thermally fitted to the shaft in a thermal process that hardens the wave generator sleeve 30 . In some embodiments, the wave generator sleeve 30 is directly fitted to the input 12 with a high-strength adhesive. Regardless of the precise manner in which the wave generator sleeve 30 is directly fitted onto the input 12 , the wave generator sleeve 30 comprises a hardenable material that is well-suited for a hardening process that allows the wave generator sleeve 30 to support a bearing assembly 31 located radially outwardly of the wave generator sleeve 30 and radially inwardly of an outer bearing race 33 . The material of the wave generator sleeve 30 may be steel, a steel alloy, a stainless steel, or any alternative having properties similar to any of the examples provided. In some embodiments, the wave generator sleeve 30 is formed of a material similar or identical to the material of the rotor. In other embodiments, the wave generator sleeve 30 is formed of a material different than that of the rotor.
As the input 12 rotates the wave generator sleeve 30 , the wave generator sleeve 30 causes the flexible gear 20 to rotate in the opposite direction from wave generator sleeve 30 .
Advantageously, by directly fitting the wave generator sleeve 30 on the input (i.e., shaft), additional fastening and intermediate components are eliminated, thereby reducing the volume, mass, and inertia of the overall system, while increasing power density.
In operation, the harmonic drive assembly 10 steps down the input 12 to the output 14 . The input 12 rotates the wave generator sleeve 30 at a first rate in a first direction. The wave generator sleeve 30 rotates the flexible gear 20 inside the ring gear 24 at a second rate that is slower than the first rate, and in a second direction opposite to the first direction. For example, if the flexible gear 20 has x teeth, and the ring gear 24 has x+1 teeth meshing with the x teeth of the flexible gear 20 , then the flexible gear 20 will rotate at 1/x the rate in the opposite direction as the rate of the input 12 and the wave generator sleeve 30 . The ring gear 24 is a rigid circular ring having a plurality of radially-inwardly oriented teeth. The flexible gear 20 and the wave generator 30 are placed inside the ring gear 24 , thereby meshing the radially-outwardly oriented teeth of the flexible gear 20 and the teeth of the ring gear 24 . Because the flexible gear 20 has an elliptical or lobular shape, its teeth only mesh with the teeth of the ring gear 24 in select regions of the flexible gear 20 . As noted above, there are fewer teeth on the flexible gear 20 than there are on the ring gear 24 , so that for every full rotation of the wave generator 30 , the flexible gear 20 would be required to rotate a slight amount backwards relative to the ring gear 24 . Thus, the rotation action of the wave generator 30 results in a much slower rotation of the flexible gear 20 in the opposite direction, and a higher reduction ratio is thereby achieved.
While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.
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A harmonic drive includes a flexible gear. Also included is a ring gear that meshes with the flexible gear. Further included is a rotor. Yet further included is a wave generator sleeve directly fitted over an outer surface of the rotor, wherein the wave generator sleeve is disposed radially within the flexible gear. Also included is a bearing assembly disposed between the wave generator sleeve and the flexible gear, wherein the wave generator rotates the flexible gear as the wave generator sleeve is rotated by the rotor.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefits of U.S. Provisional Patent Application No. 60/339,012, filed on Dec. 7, 2001, and U.S. Provisional Patent Application No. 60/391,301, filed on Jun. 25, 2002. This application incorporates by reference herein the subject matter presented in each of those provisional applications.
BACKGROUND OF THE INVENTION
[0002] One of the great advantages provided by computing devices is the ability of two or more people to communicate virtually instantaneously over great distances. One type of communication thus possible is text-only, where one person creates and transmits a text-only message to another person, or a plurality of other people, using commercially available e-mail software, for example. Text-only e-mail messages consume relatively small amounts of network bandwidth as they propagate over a network, and also consume a relatively small amount of memory or disk space on the recipient's computing device.
[0003] While the processing power of computing devices continues to increase, people increasingly desire to communicate various multi-media content alone or along with text. For example, it is now common to send a text e-mail message with attached or embedded media content. However, in order for the recipient to view, hear or display the content, a relatively large software application is typically required to be installed on the recipient's computing device. For example, for a photograph attachment to an e-mail, the recipient must have a suitable photo viewer (e.g., Microsoft Photo Editor) installed on their computing device (or installed on a network to which their computing device may connect) in order to view the photograph. That shortcoming is further exacerbated for hand-held computing devices, which are typically limited by the size and resolution of their displays, and by their available memory. Thus, certain types of computer users (e.g., workers in an office environment provided with computing devices that cannot access various type of content) and certain types of computing devices (e.g., hand-held computing devices) may not have the capacity to store a laundry list of programs needed to access various types of media content that may be sent with e-mail and the like.
[0004] As another example, there is also an increasing interest in the ability to create, revise and exchange music or other content between and among computing devices; typically over a network. For example, and using music for illustrative but non-limiting purposes, it is desirable to create a musical composition and send that composition to a recipient over a network. It is also desirable for the recipient to be able to play back the composition, revise the received composition, or create a new composition. In any case, the recipient may send the revised or new musical composition back to the original sender, and/or on to additional recipient(s). However, such communication typically requires that both the sender and recipient(s) have compatible software installed on (or available to) their respective computing devices that will enable play-back, revision, creation, and transmission of the musical composition. That software may require a significant amount of disk space on the user's computing device.
[0005] Accordingly, it is desirable to provide a method and system of communicating, creating and interacting with content between and among computing devices that overcomes the above-described and other shortcomings of the prior art.
SUMMARY OF THE INVENTION
[0006] It is thus desirable to provide a method and system for communicating, creating and interacting with content between and among computing devices utilizing existing/universal platforms, rather than via proprietary software. It is also desirable to provide a method and system of communicating content between and among computing devices in a manner that reduces bandwidth and storage size requirements. The present invention provides those and other novel and non-obvious improvements over the prior art.
[0007] Generally speaking, in accordance with the present invention, a system and method are provided for communicating, creating and interacting with content between and among computing devices. As used herein, the term “content” refers to any information that may be communicated between two computing devices. Content may include, by way of example and not limitation, text data, numeric data, photos, videos, graphics (still and animated), audio, music, combined audio and video, streaming media (e.g., music, video, audio, combined video and audio), any combination of the foregoing, and all other types of digital or analog information that may be communicated by one computing device and received by one or more other computing devices. If web-based e-mail is used, then the client software need not be able to communicate e-mail on its own, but rather, it provides access to an online e-mail system.
[0008] In a preferred embodiment of the invention, a musical composition is transmitted along with or as part of an e-mail message. The recipient of the e-mail message can play back a musical composition, revise it, save it, create a new musical composition, load a previously saved composition, and transmit a musical composition to the original sender and/or to additional recipient(s). In a preferred embodiment of the invention, the only limitation on each sender/recipient computing device is the ability to provide an audio output (by speaker, headphone, etc.), and client software that facilitates the transmission and reception of e-mail. The elimination of the need for conventional client-based software application(s) for music play back, creation, revision, and transmission, is advantageously achieved by the present invention by transmitting with an e-mail a tag to load an applet (also referred to as a client component and described in more detail below) from a server and operable in connection with a plug-in platform or plug-in such as, for example, a Shockwave or Flash plug-in. No other client software is required.
[0009] In a preferred embodiment of the invention, functionality is added to a user's computing device by an applet or plug-in available from a web server. The applet facilitates the composition, revision, saving, retrieving, creation and transmission of a musical composition to one or more recipients. Various other functionalities provided by the applet of the present invention are described in further detail herein, with variations thereof being contemplated by and within the scope and spirit of the present invention.
[0010] An applet in accordance with the present invention is preferably operable in connection with any computing platform (including, but not restricted to, personal computers, cellular/mobile phones, personal digital assistant devices, and any other device capable of processing, inputting/outputting, and transmitting/receiving content) and allows a user to create musical compositions in the various manners described herein. One embodiment of the present invention is operable in connection with Shockwave plug-in technology. Another embodiment of the present invention is operable in connection with Flash plug-in technology. Moreover, the present invention contemplates operation in connection with other plug-in technologies, now known or hereafter developed, that aspect not being a limitation of the present invention, but more a matter of design choice. By way of non-limiting example, hardware implementation could be employed, such as incorporation into a telephone receiver.
[0011] A musical composition created in accordance with the embodiments of the present invention may include one or more tracks (e.g., drum, bass, rhythm, and lead), each track being selectable by a user from a pre-recorded bank of audio samples. The bank of samples may reside locally on the user's computing device, or remotely, being accessible via a network in the latter case. Also, the samples may be loaded on the user's computing device unitarily, with the entire sample bank being loaded at once, or individually, as requested by the user. The samples may be compressed versions of waveform data, where each sample is played back by the computing device. Alternatively, the samples may be MIDI data samples, in which case the actual sound tones are generated by the computing device. The specific format and type of samples used in connection with the present invention not being critical, but rather a routine matter of design choice.
[0012] The applet also provides the user with control over any number of related audio play back parameters, such as stopping, playing, or pausing the current composition, or the attributes of each track, such as the selected sample sound, or volume, pan, and the ability to instantly mute and/or solo any one or more tracks. Effects, such as reverb, chorus, delay, and distortion, may also be used on individual tracks or the entire musical composition (also referred to as the mix) using appropriate software.
[0013] All interaction with the applet can be performed either on-screen using the computer device's cursor control device to click and drag and drop on elements of the visual interface, or via keyboard shortcuts (such as pressing the keys 1-4 to control muting status for tracks 1-4, respectively). As the present invention is applicable for virtually any computing device, including by way of illustration and not limitation, a cell phone, a microwave oven, server accessible via voice over the phone, or interactive television, the input methods may be numerous and varied (e.g., either via voice or some sort of tactile control).
[0014] The user of the applet can save, load, or transmit one or more musical compositions. Saving and loading can occur locally to the user's computing device, using local storage, or on a server, via a network. Transmission of the musical composition can occur via e-mail, or via any communication medium utilizing any computing device suitable for providing the functionality required by the present invention. For example, a user could create a musical composition on a cell phone (either as a local program or connecting to a server via wireless networking), interacting via voice or keypad, and transmit the composition as a voicemail, a regular phone call, or an e-mail.
[0015] The present invention is preferably server-based, and includes a client component and a server component. The server component preferably resides on a web server and comprises active server pages (.asp) software code to provide the various functionality of the present invention, as described in more detail herein. The client component is also referred to herein as the applet or plug-in (software code), and is described in further detail herein.
[0016] The client component provides an interface that enables a user to create, revise, save and transmit a musical composition. The interface provides certain functionality to the user including, by way of non-limiting example, the ability to play back a musical composition, to swap samples that comprise a musical composition, select a musical genre, save a musical composition, load a previously saved composition, and send, via e-mail, a musical composition. The interface can also provide a plurality of controls, preferably one for each track (each track corresponding to a selected sample) included in the musical composition. Each control can enable the user to separately turn each track on and off, and to adjust the volume for each track. Other functionality may also be provided by the interface, as a matter of design choice.
[0017] A user can advantageously receive the client component in one of two ways: by accessing a predetermined Internet site (e.g., the Internet address of the web server) whereby the client component is automatically transmitted to the user's computing device; or by receiving an e-mail with a tag to load the client component from the web server (the applet or plug-in of the present invention may thus be considered to be viral in that it is downloaded with each retransmission of a musical composition).
[0018] When a user receives the client component from a predetermined Internet site, the web server is located at a predetermined Internet address and interprets the user's navigation to that address as a request for the client component. Once the user's browser has been caused to navigate to the web server, the client component is automatically transmitted to the user's computing device for temporary storage on the user's hard drive and/or in the user's temporary memory (e.g., RAM, DRAM, SDRAM, etc.). The client component can also cause the interface to be displayed via the user's Internet browser (typically in a browser window). When the user receives the client component by navigating to the web server, a musical composition comprising a plurality of tracks, each track comprising a randomly selected or predetermined musical sample, is also communicated by the web server to the user's computing device. The user may then listen to and/or mix the tracks individually, change the volume of and swap the samples for each of the tracks, save a musical composition, e-mail a musical composition, and carry out various other options with regard to the creation, transmission/reception, and revise a musical composition in accordance with the present invention and as described in more detail herein. When a user desires to swap a sample, the samples could be swapped individually (download samples as they are requested by the client component), or, alternatively, all the samples could be transmitted by the web server to the user's computing device (download all samples as a “bank”, making each one instantly accessible). This difference can be achieved regardless of the manner in which the user receives the client component or applet.
[0019] If the user receives an e-mail with a tag to load the client component, the user will advantageously also receive a musical composition with the e-mail. The samples comprising the musical composition may have been selected by the sender of the e-mail. Advantageously, the samples that make up the tracks of the musical composition are not transmitted with the e-mail. Rather, a text string having an identifier indicating the network location of the samples is provided with the e-mail. The text string also serves to define certain characteristics of the musical composition including, by way of illustration and not limitation, identification of additional samples and their respective network locations, track volumes, mute settings and visual background settings, to name a few.
[0020] In a preferred embodiment of the invention, the identifier in the text string is a url and the network location is the web server, another server, or a plurality of servers. When a user receives the e-mail with a tag to load the client component, the client component may cause the recipient's computer to establish a connection to the Internet site identified by the identifiers in the text string, and may also cause that Internet site to automatically transmit one or more predetermined samples (as identified in the text string) to the recipient's computing device. No user action, such as hyperlinking or processing download instructions need be performed. With the samples and other information provided by the server or directed by the text string, the client component on the recipient's computing device can play back the musical composition sent with the e-mail. The recipient may revise that composition and save it as a new composition, revise it and transmit it back to the original sender and/or other recipient(s), send it un-revised to other recipient(s), or other options as described in more detail herein.
[0021] A musical composition may be created in a plurality of musical genres. While it is preferred that the samples of a particular musical composition all be selected from the same musical genre, it is also possible that a musical composition comprise a plurality of samples from different musical genres. A musical composition preferably comprises a plurality of separate and distinct musical tracks, with each sample comprising a separate track. Alternatively, a single-track composition is also contemplated by and within the scope and spirit of the present invention.
[0022] When a user selects a sample, a request is transmitted by the client component to a server identified by the identifier in the text string to transmit the selected sample to the client component. In addition to selecting the samples for inclusion in an e-mail, the user may mix the volume levels, and possibly other attributes of selected samples to create a musical composition and may save the musical composition. However, the musical composition need not be saved locally on the user's computing device. Rather, a text string that is a representation of the musical composition is created by the client component, and only the text string may be saved locally on the user's computing device, and/or in a manner accessible via the web server. The text string includes certain information for the musical composition such as, for example, an identifier (e.g., url) for each musical sample in the musical composition. The text string may also include information for each sample such as, for example, volume, or other useful information, as a routine matter of design choice. That text string is sent along with an e-mail-transmitted in accordance with embodiments of the present invention and provides information that enables a recipient to receive and play back the musical composition created and transmitted by the sender. Thus, only a tag to load the applet and a text string are sent with the e-mail. If a user had previously cached the client component, it will not be retransmitted by the web server. Note that if the strings are stored on the server-side, they could be kept in a database, either on the webserver or on a separate server. Then, they would be accessed via the webserver.
[0023] When a user sends a musical composition via e-mail in accordance with preferred embodiments of the present invention, the client component communicates with the web server. The web server accommodates a log of such communication, say, using a database, including the sender and recipient(s) e-mail address, text string for each e-mail and for each musical composition, and other information related to each e-mail (the webserver remains responsible for accessing and storing this data on the database/database server). The web server also preferably communicates each e-mail message from a sender to an e-mail server, which carries out the e-mail transmission to the recipient(s). It will be apparent to persons skilled in the art and from the disclosure provided herein that the web server and e-mail server described herein may comprise a single computer having software installed thereon to provide the desired different functionalities of the web server and e-mail server. Alternatively, separate computers may be provided.
[0024] Pre-recorded samples stored on the web server or on another server may be in compressed, Shockwave audio (SWA) format, Flash format, or other suitable format, as a matter of design choice. For the Shockwave embodiment, a sample or a plurality of samples may be bundled into a single file for communication by the server to the user's computing device to ensure synchronization between and among the samples in case of network latency or other network-introduced errors. For the Flash embodiment, the samples may be communicated as a library file. In either case, samples also may be communicated individually as requested by the client component.
[0025] The client component is operable in connection with a client-based e-mail application such as, for example, the e-mail application available from Microsoft Corporation under the tradename “Microsoft Outlook.” The client component is also operable in connection with a web-based e-mail application such as, for example, the e-mail applications available from Yahoo!, Inc., Hotmail, and AOL, to name a few. The client component consumes little user memory, and each pre-recorded sample is less than approximately 11.5K in size (based on a predetermined sample size (e.g., 8 seconds) and desired encoding quality (e.g., 16 kbps) and other attributes, such as mono vs. stereo and audio bitrate (such as 22.05 Khz vs. 44.1 Khz). It will be obvious to persons skilled in the art from the disclosure provided herein that file size may vary. The present invention's utilization of a compressed file format permits the client component to automatically download and begin playing a user's musical composition extremely quickly after the recipient has opened the e-mail. In addition, a user can cause the client component to be downloaded to another user by simply sending or re-sending an e-mail containing a tag to download the client component from the server.
[0026] In another embodiment of the present invention, a client component is provided that enables a user to add audio content to an e-mail (or even other types of content, such as image content, the term audio content, for simplicity, being understand to encompass such other content). The added audio content may be a predetermined sound or musical clip selected from a library file, or it can be a user-created musical composition. The client component inserts a tag (e.g., a HTML tag) in an e-mail message. The tag will direct the recipient's computing device to attempt to load and playback a Flash movie in the recipient's e-mail window. The Flash movie will be the musical composition and will playback without user intervention, preferably in a loop a predetermined number of times. The Flash movie may appear to the recipient like an Internet browser interface toolbar, and may contain certain buttons for user-control of the audio content. When the recipient opens the e-mail message containing the added audio content, the audio automatically begins to play back. Since Flash content is cached, the client component need not download the specific sound file for every message that references that file. Thus, subsequent playback of the same audio content does not require that the audio content be communicated by the server because it is cached on the client's computing device.
[0027] The client component also determines if a new or revised client component is available for download from the server. By checking for new versions of itself based on a server record of the recipient e-mail addresses, the client component can automatically prompt the user to enable the client to update itself.
[0028] Another aspect of the present invention provides for the addition of music capabilities to any interactive tool.
[0029] In addition, a user can be provided with access to pre-recorded samples of well-known artists for a plurality of genres. Thus, a user may create a musical composition for their favorite artist (music artist or otherwise).
[0030] Various other embodiments of the present invention are also contemplated. For example, an on-line (Internet-based) musical lottery, on-line karaoke, an on-line musical studio, to name a few. The above-described embodiments of the present invention may be provided individually, or in any combination, as a matter of design choice. In addition, non-musical content such as, for example, video, still picture, and others now known or hereafter developed content may also be utilized in accordance with the embodiments of the present invention.
[0031] The present invention accordingly comprises the features of construction, combination of elements, arrangement of parts, which will be exemplified in the disclosure herein, and the scope of the present invention will be indicated in the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0032] In the drawing figures, which are merely illustrative, and wherein like reference characters denote similar elements throughout the several views:
[0033] [0033]FIG. 1 is a schematic diagram of a network in connection with which the present invention may be used;
[0034] FIGS. 2 A- 2 B are flow diagrams of an exemplary method of communicating content between and among computing devices in accordance with the present invention;
[0035] FIGS. 3 A- 3 D are exemplary depictions of embodiments of an interface provided by the client component when used in connection with a Shockwave plug-in in accordance with an embodiment of the present invention;
[0036] [0036]FIG. 4 is an exemplary depiction of an e-mail interface provided by the client component when used in connection with a Shockwave plug-in in accordance with an embodiment of the present invention;
[0037] [0037]FIG. 5 is an exemplary depiction of an interface provided by commercially available e-mail software, within which is depicted an interface provided by the client component when used in connection with a Shockwave plug-in in accordance with an embodiment of the present invention;
[0038] FIGS. 6 A- 6 D are exemplary depictions of embodiments of an interface provided by the client component when used in connection with a Flash plug-in in accordance with an embodiment of the present invention;
[0039] [0039]FIG. 7 is an exemplary depiction of an e-mail interface provided by the client component when used in connection with a Flash plug-in in accordance with an embodiment of the present invention;
[0040] FIGS. 8 A- 8 C are an exemplary depiction of an e-mail interface via which a user may add sounds to an e-mail message in accordance with an embodiment of the present invention; and
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0041] Referring now to the drawings, the various embodiments of the present invention will now be discussed in detail. With reference first to FIG. 1, a system 100 is depicted for communicating, creating and interacting with content between and among a plurality of computing devices. In FIG. 1, the computing devices are connected or connectable to a communications network 200 such as, for example, the Internet. The depiction of a network 200 such as the Internet in FIG. 1 is provided as an illustrative, non-limiting example of an embodiment of the present invention, and is not intended to limit or otherwise define the scope or spirit of the present invention. The present invention is operable in connection with any type of computing device and over any type of communications network, including, but not limited to, a LAN, WAN, intranet, extranets, wireless networks, and any other now known or hereafter developed medium over which electronic, digital, and/or analog data may be communicated. Similarly, the computing device depicted in FIG. 1 and identified by reference character 300 is shown as a personal computer. However, the present invention need not be limited to any type of computing device, and may be used in connection with any computing device capable of communicating with another computing device and providing other functionality, as described in detail herein. Such other computing devices include, but are not limited to, personal digital assistants, cellular phones, web-enabled cellular telephones, hard-wired telephones, mobile computers, personal computers, Internet appliances and the like. Furthermore, the servers described herein may be of any compatible type, running any software, and the software modules, objects and plug-ins described herein may be written in any programming language. Lastly, the database and storage devices described herein may utilize any storage technology, including, for example, local computer memory, network attached storage, and any known storage medium, such as magnetic or optical.
[0042] With continued reference to FIG. 1, a system 100 for communicating, creating and interacting with content between and among computing devices in accordance with the present invention preferably comprises a web server 110 having general purpose software 112 stored on a data storage device (e.g., hard drive) and operable in connection with a processor thereof. The general purpose software may include, by way of non-limiting example, operating system software, database software, communication software, security software, and other types and categories of software that may be necessary or useful to enable a server to connect to the Internet and provide the functionality as described herein. The general purpose software just described is illustrative and non-limiting. It would be apparent to persons skilled in the art that other software may be provided on the server, as a routine matter of design choice. In addition, the web server 110 has special purpose software 114 stored on a data storage device and operable in connection with a processor thereof, as described in more detail below. The web server 110 may communicate with an e-mail server 120 which is also configured with general purpose software 112 . The web server 110 and e-mail server 120 are each “located” at a predetermined Internet address, identifiable by an url (e.g., the webserver.com and the e-mailserver.com). The interconnection between and among the servers 110 , 120 , network 200 , and user computing devices 300 may be achieved using any now known or hereafter developed interconnection and data communication devices (including both computer hardware and software), transmission medium, and methods; that aspect not comprising a limitation or inventive feature of the present invention. Thus, a detailed description of the interconnection between and among the various computers depicted in FIG. 1 need not be provided herein.
[0043] The special purpose software 114 on the web server 110 may be active server pages (.asp) and preferably controls the transmission of the client component to a user's computing device 300 , and controls transmission of a musical composition via e-mail from the user to one or more recipients via the e-mail server 120 . The special purpose software 114 on the web server 110 also facilitates the transmission of an e-mail message together with the client component and musical composition from a user to one or more recipients. When a user selects an e-mail (or send) option via the interface 500 or 800 provided by the client component 304 , the client component 304 causes an e-mail interface 600 (see, e.g., FIG. 4) to be displayed within a browser window 400 on the user's computing device 300 . The e-mail interface 600 provides a plurality of fields within which a user may enter certain information. For example, the e-mail interface 600 preferably includes a “To” field 610 within which a user may enter one or more recipient e-mail addresses, a “From” field 620 within which the user may enter his/her e-mail address, and a “Message” field 630 within which the user may enter a text message to accompany the musical composition.
[0044] When a user transmits a musical composition in accordance with the present invention, the text string 306 (see, e.g., FIG. 1) created by the client component 304 , the recipient address(es), the sender (user) address, and the text message (if any) are received by the special purpose software 114 on the web server 110 and saved in an e-mail database 118 maintained thereon. In that manner, the web server 110 manages and maintains a record of all e-mail transactions carried out in accordance with the various embodiments of the present invention.
[0045] Upon receipt of an e-mail request and the corresponding e-mail message, which may include the client component 304 , a text string defining certain characteristics of the musical composition 306 , musical composition, sender/recipient(s) e-mail addresses, and a text message, the special purpose software 114 on the web server 110 creates a new record in the e-mail database 118 , and forwards the e-mail message to an e-mail server 120 . The web server 110 and e-mail server 120 may comprise a single computer or, alternatively, they may comprise separate computers, as a routine matter of design choice. The e-mail server 120 facilitates transmission of the e-mail message to the identified recipient(s). The specifics of e-mail transmission are well known to persons skilled in the art and thus need not be described in detail herein.
[0046] When a user causes his/her Internet browser to navigate to the Internet address of the web server 110 , the web server 110 automatically transmits the client component 304 (i.e., software code) to the user's computing device 300 . The client component 304 is downloaded or cached on the user's computing device 300 . The operation of the client component 304 in connection with the user's computing device 300 is slightly different for a Shockwave plug-in and a Flash plug-in. Thus, each will be discussed separately and in detail below.
[0047] While the functionality of the client component 304 is essentially the same for the Shockwave and Flash embodiments, there are some differences between the two embodiments. For example, in the Shockwave embodiment, only the samples comprising the musical composition are initially transmitted to the user. In addition, a user may swap samples mid-play back with the Shockwave embodiment without having the musical composition restart for every sample change (although the musical composition may restart, as a matter of design choice). Also, the Shockwave embodiment only loads sample(s) as they are requested (either by the client component 304 when the musical composition is first transmitted to the user's computing device 300 or when requested by the user).
[0048] In contrast, the Flash embodiment transmits all of the samples associated with a musical composition at the time the musical composition is transmitted to the user. Thus, if a user elects to playback the composition, the samples are already cached on the user's computing device. If a user elects to mix the musical composition, the client component 304 requests all samples corresponding to the musical composition to be downloaded. As used herein, the terms sample and samples may refer to an individual sample, a plurality of sample, or a sample bank, which may comprise a plurality of sample from a particular genre, organized by a particular musical instrument (e.g., guitar, drums, bass, etc.), or categorized in some other manner, as a routine matter of design choice. Unless used otherwise, the terms sample, samples and sample bank are used interchangeably herein. Both the Shockwave and Flash embodiments can save musical compositions to the user's Internet browser cache, allowing for multiple saved versions.
[0049] With reference to FIGS. 3 A- 3 D, operation of the client component 304 in connection with a Shockwave plug-in will now be described. Upon receipt of the client component 304 from the web server 110 , or upon receipt of the client component 304 via a tag in an e-mail from another user, the client component 304 will cause an interface 500 to be displayed within a browser window 400 on the user's computing device 300 , as depicted in FIG. 3A, or within a window 710 of an e-mail interface 700 , as depicted in FIG. 5. The web server 110 also transmits a musical composition to the user's computing device 300 . In a preferred embodiment, the musical composition comprises four tracks, with a sample corresponding to each track. Those samples 116 may be randomly selected by the client component 304 , or they may be selected when a user creates a musical composition (such as when a user receives the client component along with an e-mail message). In either case, the samples are not transmitted along with the e-mail or client component 304 . Rather, each sample is identified by one or more identifiers contained in a text string that is transmitted with the e-mail or client component 304 .
[0050] FIGS. 3 A- 3 D are exemplary representations of an interface 500 provided by the client component 304 in accordance with the Shockwave embodiment of the present invention. In each instance, the client component 304 was transmitted directly by the web server 110 to the user's computing device 300 . The interface 500 includes four track controls 510 , one for each musical sample in the musical composition. Each track control 510 enables a user to separately control various aspects of each sample. For example, each track control 510 includes a volume slider. A user may also toggle individual tracks on and off for swapping (only tracks that are toggled on are swapped), mute individual tracks, and collectively or individually replace the musical samples. Using the track controls 510 , a user may mix the musical composition, incorporating desired samples, adjusting their respective volume, etc.
[0051] The interface 500 may also include a plurality of sample controls 520 that may identify different musical genres (e.g., hip-hop, rock, classic, tronic, world, funk, etc.). For each identified musical genre, one or more musical samples 116 are available from the web server 110 for incorporation in a musical composition. The sample controls 520 may also include a “play/swap” feature that enables a user to collectively or individually replace or swap musical samples, and to play back a musical composition. When a user selects a musical genre, and then selects “play/swap”, the client component 304 transmits a request to the web server 110 to transmit randomly selected musical samples 116 in the selected genre. The number of samples sent by the web server 110 depends on the track control 510 settings. More specifically, if a user toggles a track on, and the selects the “play/swap” sample control 520 , only the tracks that are toggled on will be swapped.
[0052] The interface 500 also includes transmission controls 530 that enable the user save a musical composition, send a composition by e-mail, load previously saved composition(s) (songs), connect to one or more predetermined Internet sites, and other functionality, as a matter of design choice. When a user selects the “save” option, the client component creates a text string 306 in local browser cache that includes an identifier for each sample included in the musical composition. That identifier preferably comprises the address (url) in the network 200 at which the sample is located and from which the sample may be communicated to the user's computing device 300 . The text string 306 also includes information about the url address, mute status, volume and other play back characteristics for each track. The text string 306 may be saved locally, on the user's hard drive, and/or it may be saved on the web server 110 or at some other location in the network 200 .
[0053] When a user selects the “load” option, the client component 304 causes a new screen to be displayed, within which may be displayed musical compositions previously saved by the user. If a previously saved composition is loaded, the client component 304 interprets the identifiers in the text string 306 corresponding to the loaded musical composition and communicates a request to the network location of each sample in the musical composition so that the sample may be caused to be transmitted to the user's computing device 300 .
[0054] When a user selects the “send” option, the client component 304 causes an e-mail interface 600 (see, e.g., FIG. 4) to be displayed in a window 400 of the browser. In a preferred embodiment, the e-mail interface 600 includes a “To” field 610 within which a user may enter one or more recipient e-mail addresses, a “From” field 620 within which the user may enter his/her e-mail address, name, or other personal identifier, and a “Message” field 630 within which the user may enter a text message to accompany the musical composition.
[0055] As mentioned above, the user may also receive the client component 304 via a tag included in an e-mail. As depicted in FIG. 5, the interface 500 is displayed within a window 710 of an e-mail interface, generally designated as 700 . In addition to the tag for the client component 304 , the user (recipient) receives a text string representation of the musical composition. By selecting the “play/swap” sample control 520 , the user (recipient) may cause the musical composition to play back. The user may also revise the musical composition using the track controls 510 and sample controls 520 . If the user has revised the received musical composition, the user may save it, and/or send it to the original sender and/or other recipients, as a matter of design choice. All the functionality available to a user who received the client component 304 directly from the web server 110 is also available to a user who receives the client component 304 with an e-mail.
[0056] Referring next to FIGS. 6 A- 6 D, the operation of the client component 304 in connection with a Flash plug-in will now be described in detail. An exemplary interface 800 provided by the client component 304 when used in connection with a Flash plug-in is depicted in those figures. It should be noted that the interface 800 differs depending upon the functionality being provided by the client component 304 , as described in more detail below. It should also be noted that FIGS. 6 A- 6 D depict the interface 800 displayed within an e-mail interface 700 . As noted previously, that is one way in which the present invention may be utilized, the other being via direct communication between the user's computing device 300 via a web browser and the web server 110 .
[0057] When a user receives an e-mail with a musical composition and a tag for the client component 304 , the interface 800 depicted in FIG. 6A is displayed. When a user selects the “Play” button 820 , the four samples that comprise the musical composition are loaded from the web server 110 to cache memory on the user's computing device 300 , as depicted in FIG. 6B. Once the four samples are loaded into memory of the user's computing device 300 , the interface 800 depicted in FIG. 6C is displayed. The user may then select the “Play” button 820 to cause the musical composition to play back, and the “Stop” button 810 to stop play back. It the user desires to create a new musical composition, the “Make New Mix” button 830 may be selected. When that occurs, all samples available for a particular musical genre or corresponding to a sample bank are loaded from the web server 110 to cache memory on the user's computing device 300 . The interface 800 depicted in FIG. 6D is then displayed. The user may then create a musical composition using the controls provided via the interface 800 , in much the same manner as described above with regard to FIGS. 3 A- 3 D. At this point, the functionality of the Shockwave and Flash embodiments of the present invention function essentially the same, save for differences in their respective interfaces. It will be obvious to a person skilled in the art and from the disclosure provided herein that the number of samples described in the preceding exemplary embodiment are by way of illustration, and not limitation, and that any number of samples may be provided, as a routine matter of design choice.
[0058] A musical composition may be sent via e-mail to one or more recipients using an e-mail interface 800 , such as is depicted in FIG. 7.
[0059] The web server 110 generally serves and manages a web page or a plurality of web pages at a predetermined Internet site, provides for transmittal of web pages (e.g., HTML, DHTML), and provides for communication of the client component to a recipient. The web server software may also provide for the storage, retrieval, and transmission of one or more musical samples 116 . The special purpose software 114 of the web server 110 also provides functionality to transmit a sample or a plurality of samples to a user via the network 200 . Alternatively, the musical samples may be stored on another server, as a matter of design choice, and transmission of a sample may be facilitated by that server or by the web server 110 .
[0060] Referring next to FIGS. 2A and 2B, a method for communicating content between and among computing devices in accordance with embodiments of the present invention will now be discussed. The flow diagrams depicted in FIGS. 2 A- 2 B are directed to the embodiment in which a user receives the client component 304 by causing a computing device 300 to connect to the web server 110 .
[0061] At step 1000 , the web server receives a request from the user's computing device 300 to transmit the client component 304 . That step occurs automatically when the user causes his/her computing device to navigate to the web server's Internet address via a web browser. In response, at step 1100 , the web server transmits to the user the client component 304 (applet or plug-in) and a musical composition comprising a plurality of tracks, each track comprising one of a plurality of samples. As noted above, the samples are not transmitted initially with the client component 304 , rather a text string including identifiers for the location(s) of the samples is transmitted.
[0062] Once the user has received the client component 304 and musical composition, various functionality provided by the client component 304 is available to the user with regard to the musical composition. For example, and with reference to FIG. 2B, at step 2000 , the client component 304 may request a sample from the server 110 (if the user selected to swap one or more samples of the composition). In response, the web server 110 communicates a sample to the user's computing device 300 , at step 2100 . Alternatively, the client component 304 may request that the web server 110 transmit a previously saved musical composition, at step 2200 , or the client component 304 may retrieve a previously saved composition stored locally on the use's computing device 300 .
[0063] The web server 110 or user's computing device 300 attempts to locate the requested musical composition, and communicates it to the user's computing device 300 , at step 2300 . Yet another alternative is that the client component 304 request that the web server 110 or user computing device 300 save a musical representation, at step 2400 . In that case, the client component 304 communicates a representation of the musical composition to the web server 110 or user's computing device 300 for storage thereon.
[0064] In yet another alternative, the user may elect to send a musical composition to one or more recipients. At step 1200 of FIG. 2A, the client component 304 (in response to a request by the user to send the musical composition via “Send” button) communicates a text message and a representation of the musical composition to the web server 110 . At step 1300 , the web server 120 creates and transmits the e-mail message to an e-mail server 120 which, at step 1400 , transmits the e-mail, including a tag for the client component 304 and the musical composition, to the recipients.
[0065] In yet another embodiment of the present invention, an audio component such as a music or sound sample (collectively referred to herein as “sounds”) may be added to an e-mail, instant message (e.g., SMA, MMS, text message, etc.), chat session, etc. Although applicable to all of the foregoing, and other now known and hereafter developed equivalents, this embodiment will be described in terms of an e-mail message; it being obvious to a person skilled in the art and from the disclosure provided herein that such description includes all such variations of this embodiment of the present invention. The added sound sets a “mood” for the e-mail (e.g., happy, sad, cool, mad, celebrate, etc.) In accordance with this embodiment, when composing a text message, a user may select one of a plurality of preprogrammed sounds that will automatically playback when the recipient of the text message receives and opens the message. Client software such as, for example, a plug-in, is installed on a user's computing device in any now known or hereafter developed manner including, by way of example and not limitation, download from a predetermined Internet site, CD-ROM, and pre-installation by a computing device manufacturer, to name a few. The client software includes a core set of sounds that may be added to an e-mail message, as described below.
[0066] With reference next to FIGS. 8 A- 8 C, the above-described embodiment of the present invention will now be discussed in detail. The client software may add functionality to the e-mail interface 700 , including a button 720 that provides a user with access to a pulldown menu 730 which displays representations of a plurality of sounds 740 available to the user for addition to the e-mail message. Alternatively, the user may select a sound by browsing the Internet for available sounds, or the user may compose an audio composition via an interface (see, e.g., FIGS. 3 A- 3 D) that permits the user to select and mix a plurality of sounds; with the sounds being stored locally (on the user's computing device or a data storage device connectable to the user's computing device), remotely (on a server or servers connectable to the user's computing device via a network), or available to the user in real-time, as a matter of design choice. The pulldown menu 730 also displays other options 750 available to the user for adding sound to the e-mail message or for updating the plurality of sounds 740 .
[0067] Moreover, it will be appreciated that forms of data other than sound content, for example, images, also could be associated with the e-mail message. Further, the message to which the other data is associated need not be limited to text; this invention also could be employed with voice messages, say, by playing an audio cue along with a live telephone call or pre-recorded telephone message.
[0068] Prior to selecting a sound, a user may sample the sounds via a sample interface 760 , as depicted in FIG. 8C. The sample interface 760 provides a sample window 762 within which are depicted graphical representations 780 of each of the plurality of available sounds 740 . When a user selects one of the graphical representations 780 , the sound associated therewith is played back to the user. In one embodiment, a sponsor may be associated with a particular sound. When the user selects the graphical representation 780 for that sound, a sponsor logo 764 is displayed in the sample interface 760 . Thus, a plurality of sponsors may elect to have an association established between their respective brand and a sound. Also provided in the sample interface 760 are user-selectable buttons for creating an e-mail message 766 and closing the sample interface 760 , depicted as a “Cancel” button 768 in FIG. 8C.
[0069] In use, a user creates a text e-mail message using the e-mail software. When the text message is complete, or at any time during creation of the message, the user may select one of the plurality of sounds 740 via the pulldown menu 730 to add to the e-mail message. When a user has selected a sound (or composed a mix of sounds) for inclusion with the e-mail message, the client software inserts HTML tags in the e-mail message at the time the message is sent. The inserted HTML tags instruct the recipient's e-mail software to attempt to load a Flash movie (from a server) within the e-mail message. The Flash movie may be displayed anywhere within the e-mail message, and may be depicted graphically, as part of the e-mail interface, or it may be hidden (with the sound still being audible to the recipient), as a matter of design choice. The selected sound is contained within the Flash movie, so as the HTML e-mail loads the Flash movie, the sound is part of that transfer, since it is embedded within. The Flash movie can have the look and feel of a Windows toolbar, and may thus appear to be a part of the e-mail interface 700 . The Flash movie may include a plurality of controls for the sound such as, for example, volume, a link to listen to the sound (in case the Flash movie doe not function as intended by the present invention), and a link to download the client software (i.e., the plug-in). The Flash movie will also load the selected sound from a server for playback simultaneous with the recipient's reading of the e-mail message.
[0070] For users having the client software already installed on their respective computing devices, receipt of e-mail with a HTML tag for a sound in accordance with this embodiment of the present invention will cause the sound added to the e-mail to be replicated on the user's computing device, thereby making it unnecessary to download sound(s) each time a user desires to attached a sound to an e-mail message. The client software resident on the user's computing device will store and maintain the sound(s) on the user's computing device. On the other hand, when a recipient receives an e-mail message with a HTML tag for a sound, the Flash movie will always be downloaded when the recipient opens the e-mail message, unless the Flash movie for a particular sound was previously cached and remains cached when the recipient opens the e-mail message.
[0071] It should be noted that the various embodiments of the present invention have been described herein in terms of operation in connection with a personal computer connected or connectable to the Internet. Such description is provided by way of illustration, and not limitation. The present invention need not be limited, and is not intended to be limited to any type of computing device. Moreover, the type of network in connection with which the present invention is utilized also need not be limited in any manner to the networks described herein.
[0072] As used herein, the terms “computer” and “computing device” are intended to be construed broadly, and in a non-limiting manner, and to include, without limitation and by way of illustration only, any electronic device capable of receiving input, processing and storing data, and providing output (both input and output typically being digital data), and that is connectable in any manner and by any means to a network such as, for example, the Internet. A computer may be a computer of any style, size, and configuration including, without limitation, a server, workstation, desktop, laptop, Internet appliance, notebook, personal digital assistant (PDA), cellular phone (Internet enabled or otherwise), or other now known or hereafter developed device. A computer typically includes the following components: a central processing unit (CPU or processor) operable in connection with software (e.g., operating system, application programs, etc.), a hard drive unit (HDU), permanent memory (e.g., ROM), temporary memory (e.g., RAM, DRAM, SRAM, etc.), a removable data storage device (e.g., CD/DVD drive, floppy drive, etc.), an input device (e.g., keyboard, mouse, trackball, etc.), an output device (e.g., monitor or display), and an I/O device (e.g., modem, infra-red transmitter/receiver, radio (cellular) transmitter receiver, etc.). It is known to a person skilled in the art that a computer may comprise some or all of those components, in addition to components not listed.
[0073] The terms “communicate”, “transmit” and “receive” (and variations thereof) are used herein to refer to the exchange of data within a single computer (e.g., between and among any of a script, an application, a control, etc.), and/or to the uni-directional or bi-directional exchange of data between one or more computers.
[0074] While the present invention and the disclosure provided herein is primarily directed to music as the content, other content is also contemplated by and within the scope and spirit of the present invention. For example, the present invention may utilize MIDI content, which directs a MIDI playback device via hardware and/or software. The present invention may also utilize video/animation content.
[0075] It will be obvious to persons skilled in the art that the functionality of a computing device such as, for example, a server, is determined in large part by the software which controls the server processor. Thus, a description herein of a plurality of servers providing a plurality of functionality may also be embodied as a single server providing a plurality of functionality. Conversely, a description herein of a single server providing a plurality of or a specific functionality may be embodied as a plurality of servers providing a plurality of or a specific functionality.
[0076] Thus, while there have been shown and described and pointed out novel features of the present invention as applied to preferred embodiments thereof, it will be understood that various omissions and substitutions and changes in the form and details of the disclosed invention may be made by those skilled in the art without departing from the spirit of the invention. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.
[0077] It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.
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A system and method for communicating, creating and interacting with content between and among computing devices. A musical composition may be transmitted along with or as part of an e-mail message. An applet is provided that enables a user to play back, revise, create, and transmit musical compositions without having to download large software applications by utilizing short repeating loops of music that permit hi-fidelity sound quality without the normally required large file size. Each sender/recipient computing device has the ability to provide an audio output, and has client software that facilitates the transmission and reception of e-mail. In addition, a Shockwave, Flash, or other similar plug-in (or hardware and/or software playback logic) is also required. Special purpose software is provided on a server to facilitate communication of a musical composition via e-mail, or other techniques such as instant messaging, chat, or even voice) between and among computing devices over a network such as the Internet. In yet another embodiment, a first user may add a sound to a text message that is played back simultaneously with the recipient's reading of the text message.
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CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority of Taiwanese application No. 099145518, filed on Dec. 23, 2010.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates to an epitaxial structure and a method for making the same.
[0004] 2. Description of the Related Art
[0005] A substrate, which is suitable for epitaxial growth of an epitaxial layer in an optoelectronic device, often has poor thermal or electric conductivity. Therefore, in consideration of the above problems and the epitaxial quality, the fabrication of the optoelectronic device usually includes a step of removing the epitaxial layer from a temporary substrate used for epitaxial growth of the epitaxial layer.
[0006] However, as disclosed by Ji-Hao Cheng, et al., in “Effects of laser source on damage mechanisms and reverse-bias leakages of laser lift-off GaN-based LEDs,” Journal of The Electrochemical Society, 156 (8), H640-H643 (2009), when the temporary substrate is removed from the epitaxial layer using a laser lift-off process (i.e., the removing step), the quality and function of the epitaxial layer are adversely affected.
SUMMARY OF THE INVENTION
[0007] Therefore, an object of the present invention is to provide an epitaxial structure and a method for making the same that can overcome the aforesaid drawbacks associated with the prior art.
[0008] According to a first aspect of this invention, a method for making an epitaxial structure comprises:
[0009] (a) providing a sacrificial layer on a temporary substrate, the sacrificial layer being made of gallium oxide; and
[0010] (b) growing epitaxially an epitaxial layer unit over the sacrificial layer.
[0011] According to a second aspect of this invention, an epitaxial structure comprise:
[0012] a temporary substrate;
[0013] a sacrificial layer formed on the temporary substrate, and made of gallium oxide; and
[0014] an epitaxial layer unit epitaxially grown over an upper surface of the sacrificial layer opposite to the temporary substrate.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Other features and advantages of the present invention will become apparent in the following detailed description of the preferred embodiments of the invention, with reference to the accompanying drawings, in which:
[0016] FIG. 1 is a flowchart illustrating the first preferred embodiment of a method for making an epitaxial structure according to the present invention;
[0017] FIGS. 2 to 7 are schematic diagrams illustrating consecutive steps of the method illustrated in FIG. 1 ;
[0018] FIG. 8 is a schematic diagram illustrating a step of patterning a sacrificial layer in the second preferred embodiment of a method for making an epitaxial structure according to the present invention; and
[0019] FIG. 9 is a schematic diagram illustrating a step of forming second sacrificial layers in the third preferred embodiment of a method for making an epitaxial structure according to the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0020] Before the present invention is described in greater detail with reference to the accompanying preferred embodiments, it should be noted herein that like elements are denoted by the same reference numerals throughout the disclosure.
[0021] Referring to FIG. 1 , the first preferred embodiment of a method for making an epitaxial structure according to this invention comprises the following steps.
[0022] In step 10 , a temporary substrate 2 is provided (see FIG. 2 ). The temporary substrate 2 is made of, for example, sapphire (Al 2 O 3 ), silicon, silicon carbide, etc.
[0023] In step 11 , a sacrificial layer 3 , which is made of gallium oxide, is formed on the temporary substrate 2 (see FIG. 3 ). The temperature for forming the sacrificial layer 3 preferably ranges from 200° C. to 700° C., and is more preferably 400° C. The gallium oxide layers grown under these temperatures show various crystalline quality. The temperature for forming the gallium oxide, especially Ga 2 O 3 is more preferably 400° C. because the sacrificial layer 3 can be easily removed.
[0024] The sacrificial layer 3 can be formed using metal organic chemical vapor deposition (MOCVD), pulsed laser deposition (PLD), etc. When using PLD, the pressure of a chamber for conducting PLD preferably ranges from 0.1 to 10 −4 torr, and the forming rate of the sacrificial layer 3 preferably ranges from 0.1 to 1 micron/hour.
[0025] In step 12 , an epitaxial layer unit 4 is grown epitaxially over the sacrificial layer 3 ( FIG. 4 ). In the initial period, the epitaxial layer unit 4 is grown at a lower temperature (500˜600° C.) in a nitrogen atmosphere. Hydrogen is not used in the initial period. Thereafter, the epitaxial layer unit 4 is grown at a higher temperature (700˜1100° C.) in an atmosphere including nitrogen and hydrogen.
[0026] When the epitaxial layer unit 4 is formed at the lower temperature in the nitrogen atmosphere (without hydrogen), the gallium oxide of the sacrificial layer 3 can be protected and will not be decomposed into gallium-rich oxide or gallium during the epitaxial environment.
[0027] With increasing temperature and introducing hydrogen, the epitaxial layer unit 4 has improved epitaxial quality.
[0028] The epitaxial layer unit 4 is made of gallium nitride.
[0029] In step 13 , a permanent substrate 5 is formed over the epitaxial layer unit 4 opposite to the sacrificial layer 3 (see FIG. 5 ). Based on actual requirements, the permanent substrate 5 may be made of copper, silicon, molybdenum, etc. Otherwise, the permanent substrate 5 may be a flexible circuit board.
[0030] In step 14 , an etchant is introduced to etch the sacrificial layer 3 and to remove the temporary substrate 2 and the sacrificial layer 3 from the epitaxial layer unit 4 (see FIGS. 6 and 7 ). In this embodiment, the etchant is HF.
[0031] FIG. 8 illustrates the second preferred embodiment of a method for making an epitaxial structure according to this invention. The second preferred embodiment differs from the first preferred embodiment in that the sacrificial layer 3 is patterned to have a plurality of grooves 31 . Because the epitaxial layer unit 4 will not be fully filled into the grooves 31 , the temporary substrate 2 can be removed more efficiently due to multiple flow paths of the etchant. The sacrificial layer 3 with grooves 31 can then be etched faster than that without grooves.
[0032] FIG. 9 illustrates the third preferred embodiment of a method for making an epitaxial structure according to this invention. The third preferred embodiment differs from the first preferred embodiment in that the method of the third preferred embodiment further comprises a step of forming two second sacrificial layers 6 on upper and lower surfaces 32 , 33 of the sacrificial layer 3 . Each of the second sacrificial layers 6 is independently made of a nitrogen-containing material or a silicon-containing material, and has a thickness greater than 0.001 micron. The nitrogen-containing material may be a nitride having an atomic percentage of nitrogen greater than 20%, such as gallium nitrogen, indium gallium nitride, etc. The silicon-containing material may be a silicide having an atomic percentage of silicon greater than 30%, such as silicon film, silicon nitride, etc.
[0033] After removing the temporary substrate 2 from the epitaxial layer unit 4 by etching the sacrificial layer 3 , the second sacrificial layers 6 are removed. The etchant for the sacrificial layer 3 shows a very low etch rate for the second sacrificial layers 6 . After separating the temporary substrate 2 and the epitaxial layer unit 4 , the two second sacrificial layers 6 can be easily etched out by using another etchant, especially KOH. The two second sacrificial layers 6 can protect the surfaces of the temporary substrate 2 and the epitaxial layer unit 4 during the long etching process of the sacrificial layer 3 .
[0034] In other preferred embodiments, the second sacrificial layer 6 can merely be formed on one of the upper and lower surfaces 32 , 33 of the sacrificial layer 3 .
[0035] While the present invention has been described in connection with what are considered the most practical and preferred embodiments, it is understood that this invention is not limited to the disclosed embodiments but is intended to cover various arrangements included within the spirit and scope of the broadest interpretations and equivalent arrangements.
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A method for making an epitaxial structure includes: (a) providing a sacrificial layer on a temporary substrate, the sacrificial layer being made of gallium oxide; and (b) growing epitaxially an epitaxial layer unit over the sacrificial layer.
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[0001] This application claims the benefit of U.S. Provisional Patent Application Serial No. 60/273,460, filed Mar. 5, 2001.
BACKGROUND OF THE INVENTION
[0002] This invention relates generally to the field of cabling systems for homes or other buildings, where the cabling systems are structured to provide electronic communication between various home automation and electronic devices. It relates more particularly to pre-wired infrastructure systems which connect to, control and provide electronic communication from various devices in a home, such as telecommunication devices, computer networks, TV and audio distribution, speakers, infra-red controls, and home control components. These may also include lights, appliances, HVAC, security, drapes/blinds, fans, audio-video equipment, cameras, CCTV, phones, intercoms, computer networks, door locks, irrigation, plumbing, driveway sensors, pool/spa equipment, weather stations, pet control, etc.
[0003] The number of household electronic devices developed for consumer use and for operation of systems which were previously manually actuated has increased dramatically in recent years. New developments in microprocessor equipment and “self-intelligent or smart” appliances have made it possible to provide a home owner with unprecedented opportunities in convenience. The concept of pre-wiring a home during construction for basic electronic communication has grown from simply providing separate wiring or cabling to bring in telephone and cable TV, as well as mounting audio speakers in different rooms all communicating with a single stereo, to the current status where practically any functioning equipment in a home can be controlled from remote locations and where electronic communication between equipment in separate rooms provides multi-directional control and output.
[0004] It is now known to pre-wire a home during construction to provide control and/or output jacks in multiple rooms, such as for placement of telephones, computers, cable TV, speakers, etc. The currently known systems, however, suffer a major drawback in that they are engineered either in customized format in response to specific choices as to what equipment will be utilized at what location in a house, or they are engineered in preset package form attempting to cover the most common situations likely to be encountered. Both these systems cannot adapt to change, whether the change comes about from decisions to utilize different equipment in unforeseen locations, from new equipment being added after the home is fully constructed, or from new technology which did not even exist at the time of construction. Such changes require the home to be rewired or retrofitted.
[0005] As little as five years ago, there were little or no sources for structured cabling. Early types of structured cabling only supported video, phone, and networking. Even the emerging, more “advanced” packages only include additional cabling for audio. The current systems do not begin to address the issues of home automation, just standard distribution of existing signals in the home.
[0006] It is an object of this invention, therefore, to provide a universal cabling or pre-wire system which is not vulnerable to the problems encountered by the known systems, in that the invention provides a cabling system which can be adapted to a multitude of changes without the need to rewire, which can accommodate new technological developments without the need to rewire, which provides control and usage options for various types of electronic equipment not available under the known systems.
SUMMARY OF THE INVENTION
[0007] The invention is a universal cabling or pre-wiring system which is installed in a home or other building during construction of the home, the system providing electronic communication between a multitude of electronic devices and electronic control devices, where the system can accommodate changes in location or type of equipment, can receive additional equipment not originally contemplated, can receive equipment not yet developed, such that any home design can be pre-wired in a generally standardized format. The system utilizes known wire and cable with optimum ratings, specifically CAT5 (unshielded twisted pair wiring rated at 100-150megahertz and 100 megabits/sec), CAT5E (shielded twisted pair wiring rated at 350 megahertz and 150 megabits/sec), RG6 Quad Shield (coaxial cable), 16/4 (audio wire) and 16/2 (audio wire), provided in a unique combination and arrangement which maximizes functionality. The system incorporates a main distribution and control center and a home theater distribution and control center, in communication with each other and the various multimedia room outlets. Multimedia outlets in a given room are provided in specific communication patterns such that the functionality is increased.
DETAILED DESCRIPTION OF THE INVENTION
[0008] The invention will now be described in detail as to the system and the methodology. It is to be understood that the specific grades or designations of various cables is a reference to the state of the art at this time, such that substitutions of equivalent or upgraded cables having differing or higher designations is contemplated within the invention, such that the system will always maintain the maximum capability for communication with upgraded and improved devices, appliances, electronic components, etc. It is also to be understood that, while the system is described as related to a home, the system and methodology are applicable to commercial and industrial buildings.
[0009] This system offers the versatility to pre-wire the home during construction in a universal system which is capable of handling multiple electronic components, such that the home owner has the ability to upgrade, add, and expand to different products from many manufacturers, using a multitude of standards and protocols to control and use a variety of existing and emerging technologies, appliances and products, at any time after construction without the need to re-wire or limit choices related to new electronic devices. This frees the owner during the building of the home from the worry of finding, learning about, and understanding or knowing any and everything the owner my want in future. Once the universal cabling infra-structure is in place, they can then learn about and determine what they want to add to the system.
[0010] A homeowner utilizing the invention can at any time add an analog or digital phone system, which can distribute up to 8 incoming phone lines to up to 24 rooms, also allowing the homeowner to answer and unlock the door from any phone in the home including wireless 900 MHz or 2.4 GHz phones. At the same or later time, they can add X10 lighting control by SmartLinc, Leviton or X10Pro, and a Crestron, Panja, JDS Timecommander or many other control systems. This allows them to control lights from remotes, the phones, touchscreens, wallpads, the internet and more.
[0011] The system can accept products using all standard analog and digital video and audio signals, can utilize products that use RS232, RS485, ASCII, Digital IO, analog IO, contact closure, infra-red, IEEE1394, 802.11b, radio frequency, X10, powerline carrier, the point being, the client doesn't need to even know what they want or they want the house to do, we designed the UCS to take care of that. The system also includes surge protection at the head end, rated in the high nano to Pico second clamping rate, for video, electrical, and telecom.
Definitions Used Herein
[0012] Pre-wire: installation of wiring during construction of the home.
[0013] Central Distribution Point: a relatively centrally located space in the home from which the cabling infrastructure is initiated, preferably climate controlled, i.e., within the air-conditioned portion of the home, and not near electrical sub-panels or high voltage devices or wires.
[0014] Run: a length of cable from one point to another.
[0015] Structured Cabling: a cabling method wherein all cable runs extend to a single point of distribution, and wherein wall plates support multiple functions.
[0016] Home Run: a cable run from a single central point terminating in the room or location for which it is intended for use.
[0017] Loop or Looping: a method fo wiring also known as daisy chaining, where cable is connected from one point to the next, and so forth, in a series.
[0018] Trim-Out: the connection of cables to trim or wall plates, or inserts installed into a multi-port trim plate.
[0019] Punch-Down: a generic term used to describe the process of connecting wires or cables to punch blocks, central distribution hubs or bus-bars.
[0020] Sub-systems: various electrical and electronic systems in the home, such as lighting, HVAC, pools, security systems, appliances, drapes and blinds, home theaters, distributed audio, home networks, etc.
General Methodology
[0021] The system utilizes the following cable/wires: CAT5 (24g/8c), rated from 100-150 MHz or better; CAT5e (24g/4c), rated to 350 MHz or better; RG6 Quad Shield, rated to 2.4 GHZ or better; 16/4 high strand or better; 16/2 high strand or better; 18/4/5 (shielded).
[0022] Two main distribution areas are created: a central distribution point for generally non-interactive components, and an equipment room or location point, also referred to as a multimedia or home theater distribution point, for generally interactive components. These areas are preferably separate, as the equipment utilized at each area differs. Most distribution panels and equipment are designed to be mounted vertically on a wall, and is usually combined with a panel enclosure. Audio, video and control equipment is usually designed to rest on shelves, rack mount or set on a table top, and typically produce a significant amount of heat so as to require climate control and larger space for heat dispersal. The equipment room or location concept provides for frequent and easy access to the audio/video equipment, whereas access and aesthetics are not important for the distribution equipment which controls the data, communications and automation functions, i.e, the non-interactive components.
[0023] Most wires home run to the central distribution point, where a distribution panel is used to punch down and connect cabling to various services. A variety of panels from different manufacturers can be used. Distribution centers must be located in air conditioned space, as centrally located as possible, preferably in a dedicated closet or small room.
[0024] The paths should be plotted to result in the least electrical intermingling, least drilling, shortest runs, easiest runs, and fewest number of studs in between runs. Holes through studs should be separately drilled—the electrical holes should not be used to avoid parallel running with electrical wiring. Stay at least 1-4 ft from electrical cabling and only cross at 90 degrees. If running with electrical is absolutely necessary, use aluminum foil to shield wires (for short distances only). Staple cables to studs every 3-4′, and staple in center of stud. This prevents cable from moving during construction and getting nailed through during/after. Keep cables in attic spaces above walking area “no-step” process, staple to rafters. This prevents stepping on in attic, future snags, and problems, looks cleaner.
[0025] Always measure existing electrical boxes to compare box height, be consistent room to room. Measure from lower screw holes to floor (center to center), in each room and wall. Always make sure boxes are installed level and plumb. Only use plastic single gang boxes, or nothing for VC locations. During pre-wire, leave 1-2′ of cable hanging out at boxes, and 4-6′ at head end, 3-4′ at speakers-zig zag in ceiling. Always bag and tape all cables, with top of bag in wall behind box, and back straight and narrow, taped at top and bottom-inside and outside-for protection. Label outside wires and place cable labels around cables at J-box friction location.
Wire and Cable Management
[0026] Use color coding for wiring, with the following combinations suggested. All wiring is from the main distribution panel unless otherwise noted.
RG6 (video feeds) Black - out and satellite White - in and satellite Yellow - cameras, link, sub, satellite CAT5 (telecom/control) Blue - phone Green - theater link/connect wires between control systems White - HVAC, garage door, gate and various control wire Red - audio/video control wiring (IR, Elan, volume, etc.) CAT5E (PC network/HSD) Yellow - data networking 18/4/5 (interface) Gray - touchscreens, camera power, line level audio 16/4 (speakers/feeds) Green - to volume control, J-box in rooms (from home theater) Blue - loop out White - loop in (TVA20 from volume control to TV-LOC) 16/2 (speakers/local) Blue/White - for left and right speaker channels
[0027] At cable origin, either central distribution point or equipment location, wrap all cables from each room together with electrical tape and label entire bundle with room name.
General Cabling Technique
[0028] Position interface locations (keypads, touch screens, etc.) (2 CAT5 each) at:
[0029] inside front door foyer area
[0030] inside garage door entry area
[0031] back patio door location
[0032] add as needed at other egress and convenience points
[0033] 2 each CAT5 to security panel location—from distribution panel for communication and control.
[0034] 1 each CAT5 to each air handler/HVAC control panel location—from distribution panel.
[0035] 1 each CAT5 to each electrical panel and sub-panel (run to 4 ⅛×4 ⅛ box with romex between box and panel—potentially connected to a dedicated 15A breaker.
[0036] 4 each CAT5E, 1 each CAT5 home run from home theater location.
[0037] 1 each CAT5E home run from central, small PC LAN server.
[0038] 1 each CAT5E home run from any non-local LAN hub.
[0039] 1 door intercom wire—CAT5—to all main exterior doors.
[0040] 1 each CAT5, 1 each 18/4s HT to front door jam for future magnetic lock control
[0041] 2 each+DoorCams—RG6Q, 22/4, and CAT5—determine location, front and rear.
Video, Power and Control Feeds
[0042] 6 each RG6 stubbed out on southwest end of home with both best angle for reception, ease of access, and somewhat hidden from view, for HDSAT, DSS, HDTV, antennae—stubbed out alone.
[0043] You must determine the prescribed satellite angles and azimuths for your area.
[0044] 1 each RG6 for cable TV—mark with plastic or some long lasting label.
[0045] 2 each CAT5 for TELCO—allows up to 8 lines to any room.
[0046] 1 ft to side of cable TV wire—both away from SAT wires. Can add additional CAT5 to TELCO location for dedicated DSL or other HSD access direct from demarcation point.
[0047] 3 each CAT5 for future—gang together with next. use for photovoltaic cells, anemometers, weather stations, temp sensors, gate intercoms.
[0048] 1-2 each COAX, 1 each 18/4s, 1 each CAT5 for future use—i.e. gatecam, control, etc.
[0049] 1-2 each 16/4 near rear of house for external speakers.
[0050] 2 each CAT5, 1 each 18/4 shielded home run from any pool pump or interface.
[0051] 2 each CAT5, 1 each 18/4 shielded stubbed out for future solar control systems.
[0052] Calls for wall phone in master bath—each CAT5 home run
[0053] Calls for TV in niche location or counter top location, master bath, main baths—1each RG6 home run.
Room Specific Wiring
[0054] All Master bedrooms get 2-16/4 and 1-CAT5 loop from keypad/volume control location to TV location.
[0055] 1 RG6 Q loop for one 72″ wall mount TV location—intersect of two walls, high comer
[0056] All I-rooms (i.e., rooms capable of serving multiple purposes, such as a bedroom, office, den, etc.) get:
[0057] 1-16/4 home run to volume control location
[0058] 1-CAT5 home run to volume control location
[0059] 2 16/2 to local speakers—locate squarely in ceiling in center of room
[0060] 1 CAT5 home run phone location—near bedside outlet
[0061] 1 CAT5E home run phone location
[0062] 2 RG6Q home run to TV location—across from bed
[0063] 1 CAT5 loop from phone location to TV
[0064] 1 CAT5 home run to TV
[0065] Volume control/keypad/touchscreen locations are best near room or main entry doors at 45″ from the floor, and/or 8-12″ directly above the rooms light switches. Unless speakers are installed at time of construction, speaker cables with 4 to 5 feet extra length are rolled up, taped and fastened to overhanging stud, dropped directly over future speaker cut-out. Speaker wires centered to the ceiling fans or lights, oriented left and right of the beds, and covered with drywall. In master bed, or other locations where surround sound or better is desired, speakers or wires are located above bed, towards the head. A small local surround system with small front center, left and right speakers give you surround sound, with rear speakers being in ceiling.
[0066] All Media/Home Theater/Equipment Rooms get
[0067] All 16/4 home runs behind media gear
[0068] All CAT5 home runs behind media gear
[0069] 2 16/2 to local speakers—locate at rear of room, in ceiling LTBD
[0070] 2 16/2 to left and right of media center (zigzag down between studs, in wall) LTBD
[0071] 1 16/2 for center channel—(zigzag down between studs- wall center)
[0072] 4 RG6Q home run to TV location—
[0073] 1 CAT5 loop from phone location
[0074] 4 CAT5 home run
[0075] 2 CAT5E network home run to control system connectivity, MP3 recorders/servers, video-ono-demand storage and distribution
[0076] 16/4 loops to any other smaller theater rooms, cross-connecting different audio source locations
[0077] 1 CAT5 home run to phone location
[0078] 1 CAT5e home run to phone location
[0079] All Kitchens get
[0080] 1 16/4 to home theater from volume control location
[0081] 2 16/2 from volume control to ceiling or preferred speaker locations
[0082] 1 CAT5E from home theater to volume control location
[0083] 1 CAT5 home run from wall phone
[0084] 1 CAT5 loop from wall location to counter phone (optional)
[0085] 1 CAT5E home run from counter, desk niche, or in-drawer location
[0086] 2 RG6Q to counter or TV niche location
[0087] optional Appliance Cabling Package—6 CAT5 home runs to refrigerator, oven, washer/dryer, microwave, dishwasher, etc., plus single CAT5 home run to distribution center.
[0088] Lanias and patios get 1 phone/TV outlet—and 2 speakers (ceiling or surface mount). Laundry rooms are wired for audio, phone, network and video. Also see appliance package.
Trim-out Technique
[0089] Punch down involves all cables terminating in distribution panel. If not being used, it will be terminated into the appropriate patch block, which can simply be patched through to the necessary service or services.
[0090] Volume control/keypad/touchscreen locations, if unused, are to be covered by a standard single gang, blank wall plate.
[0091] Bedrooms are trimmed using Multi-port outlets in the following configuration:
[0092] At bed location—a single gang multi-port trim plate with:
[0093] 1 phone jack (RJ11 or 6 cond.)—wired using blue and orange pairs of CAT5, to 2 line POTS standard.
[0094] 1 fax/pc jack (RJ1 or 6 cond.)—wired using green and brown pairs of CAT5, to 2 line POTS standard.
[0095] 1 home LAN jack, CAT5 rated (wired to 568B standards)
[0096] (master bedroom(s) get duplicate phone jacks on either side of bed).
[0097] At TV location—a single gang multi-port trim plate with;
[0098] 1phone jack—wired using blue and orange pairs of CAT5, for POTS standard, looped back to g &
[0099] b at bed location
[0100] 1LAN Jack—(wired to 568B standards)
[0101] 2 coaxial connections
[0102] 1 unused—untrimmed CAT5 left behind plate for future use (such as Crestnet, IEE1394b, IR, etc.)
[0103] All Media Rooms are trimmed using bulkhead fittings that multiple cables feed through, or custom fitted ported outlets, for bulk audio distribution cabling. Location is usually behind audio/video equipment. Cables are trimmed accordingly. Speakers are trimmed as needed, and can be installed at a later date.
[0104] Additionally, the cabling for audio speakers, volume controls and keypad/touchscreen interfaces is run to the media center equipment location. This is for ease of adding and integrating different processors to control anything from audio/video distribution to lighting, HVAC, appliance control and more.
[0105] This system allows for maximum upgradability, scalability, and expandability with the least amount of change at each individual rooms trim plate locations. All of the changes, upgrades, etc., are made at the distribution center. There is no need to change the wiring at each rooms phone jack to add any type of phone system. TV and fax locations have utilized the g & b pairs of wires, so they can bypass phone systems and intercom systems, when added, without changing room wiring. This is due to the fact that most satellite and digital cable TV providers require a phone line to their TV converter boxes, and these cannot work with or through a phone, KSU or PBX type system. Adding a phone system without this trim configuration would result in the converters not working, and having to rewire at each TV location with a tuner/receiver that requires a direct phone connection (i.e., for interactive movie ordering, digital cable receiver or DSS receivers).
[0106] Multiple cameras can be added and viewed from any TV location in the house, by flipping to a pre-designated channel or channels. Again, without changing any trim or cabling in the individual rooms.
[0107] The coaxial ports in each room can serve multiple functions. Since there are dual outlets, video can be fed into the room via one port, and a camera or DVD from that room can be utilized by any room in the home. Additionally this can be used to provide HSD access or DSS access to the room. The key is not the coaxial, but the extra CAT5 and network connection we use, for future control and integration of that equipment, not just distributing it's signal.
[0108] At volume control locations, the homeowner has the option to choose to install and upgrade from or to standard single gang volume controls, single gang audio control keypads, double gang keypad systems, touchpads, high end touchscreens and more.
[0109] The system is compatible and upgradable with control electronic brands such as HomeDirector, ActiveHome, JDS Timecommnader/Plus, JDS Stargate, HomeBase Pro, HouseLinc, HomeVision, HAL 2000, Crestron, ELAN and others, with device controllers and subsystems such as X10, Leviton, Lutron, SwitchLinc, Panasonic, DSC, Ademco, napco, LinkSys, Channel Plus, Niles, ELAN, Kustom, Russound and others, new and emerging technologies such as IEEE 1394/Firewire, Sony Ilinc, Crestnet, MPS distribution, HD satellite ready, ADSL/HSD networking, e-appliances and others.
[0110] Where a standard multimedia outlet in a known system (prior art) usually will have an in port and an out port for cable, a port for computer networking and a port for telephone, the invention will provide a pair of multimedia outlets in a single room, where the telephone port is connected as a looped bypass, the second outlet having a telephone port and a main in port. This enables the system to provide a much improved video, telephone and computer network which is highly adaptable.
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A universal cabling or prewiring system installed in a home or other building during construction, the system providing electronic communication between a multitude of electronic devices and electronic control devices, where the system can accommodate changes in location or type of equipment, can receive additional equipment not originally contemplated, can receive equipment not yet developed, such that any home design can be prewired in a generally standardized format.
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FIELD OF THE INVENTION
[0001] This invention relates to the injection of gaseous fuel directly into the combustion chamber of a compressible gas-fueled engine. In particular, the invention provides apparatus and methods for low-pressure, high-speed direct injection of natural gas or other gaseous fuel into a combustion chamber of an engine.
DISCUSSION OF THE PRIOR ART
[0002] Natural gas processors and pipeliners have long relied upon large stationary gas engines that were designed and installed in the 1930's and 1940's. These engines have proven to be extremely reliable—unfortunately, their high levels of emissions and poor fuel economy offset their longevity. Known direct fuel injection apparatus and methods in these older gas engines occurs through orifices or nozzles at pressures (P inj ) that range from about 30 to about 60 PSIG. The pressure in the power cylinder (P cyl ) during these known injection processes is typically increased by about 20 to about 60 PSIG from an initial ambient or boost pressure. The resulting differential pressure, dP=P inj −P cyl , is small, and results in a relatively low velocity fuel jet entering the combustion chamber, which thereby causes poor mixing and an inefficient burn. This inefficient burn produces levels of pollutants that are unacceptable under current environmental requirements.
[0003] Recent government mandates call for emissions levels and fuel economies that older engines, in their current forms, are simply not capable of meeting. The only compliance options are to shut down the existing units and replace them with new engines having modern technology, modify the existing equipment utilizing new technology or purchase short-term emissions credits from other producers. All these choices are expensive, in terms of equipment, labor, and downtime. Nonetheless, public pressure and government regulators are forcing the cleanup of the exhaust emissions of these facilities, and suppliers must make critical decisions to comply with the mandates.
[0004] With respect to replacement using newer engines, the control methodology employed in modern engines involves many mechanical modifications such as turbochargers, valve overlap, pre-chambers, and computerized ignition systems, all of which increase the price of the engines. With respect to modification of older engines, these modern features simply cannot be economically added to older engine designs. In addition, many older engines are already installed in critical service applications, and upgrade or replacement downtime can quickly become cost prohibitive.
[0005] Natural gas is a combination of hydrocarbons that are typically gaseous at atmospheric pressure. Methane is by far the largest component, its presence typically accounting for 90 to 98% of the composition. The remainder is usually composed of ethane, propane, normal and iso-butane, normal and iso-pentanes and heavier hydrocarbons as well as small percentages of CO 2 and N 2 . The composition of natural gas varies significantly with geographic region and type of reservoir, however, in general the physical characteristics are nominal. It is odorless, colorless, and lighter than air, with a specific gravity of 0.58 to 0.70 (air has a specific gravity of 1.22 kg/m 3 at standard conditions). A stoichiometric mixture, in which exactly as much air as is necessary to completely oxidizes the fuel is present, typically falls in the range of 16.0 to 17.0 mass part of air to one part of fuel. The width of the range is due to varying compositions of the gas. Natural gas has a comparatively slow flame front propagation speed, only approaching 0.95 fps in a perfect mixture at standard conditions. While critical to the fuel consumption-emissions aspect, natural gas has a fairly wide combustibility range. This is a function of flame front propagation, wherein a mixture that is too lean creates a flame front propagation speed that is too slow to support combustion, while a mixture that is too rich suffers the same problem. In short, any addition of fuel to the mixture causes it to become richer than required to maintain combustion and adversely affects the flame front propagation speed. Conversely, less fuel causes the mixture to become leaner than desired with the same effect. Perhaps more importantly, poorly mixed charges can result in rich and/or lean regions within the mixture. When ignited a rich mixture creates high levels of NOx emissions, and a lean mixture creates high levels of CO and soot pollutants. Unfortunately, the stoichiometric mixture, while easy to ignite and maintain, does not offer the lowest emissions level attainable, but certainly does burn the right amount of fuel to create the optimal heat release.
[0006] It is known from combustion science that more efficient mixing of the fuel and air would create a more efficient burn. Historically, it was thought that the mixing occurred naturally as a result of the turbulence created by the air and fuel flowing through the inlet ports into the cylinder and the motion of the piston. However, the inventor has discovered that this type of mixing is not only limited in its efficiency, but in fact creates a non-homogenous mixture in several areas of the cylinder of the combustion chamber. The fact that a fairly rich, at least stoichiometric, mixture was required near the spark plug to promote ignition has induced designers to place fuel injection valves near the spark plugs. This design constraint and known designs of the valve and injection orifices have compromised mixing at the far end of the combustion chamber. Although the resulting combustion mixture usually fires, and meets the initial design criteria for older engines, the burn is extremely inefficient, creates non-homogeneous combustion, resulting in high level of combustion pressure pulsation, and higher levels of undesirable emissions such as oxides of nitrogen and carbon monoxide.
[0007] In an attempt to increase burn efficiency and reduce emissions, many designs for new stationary natural gas engines, as well as overhaul designs for older engines, call for the use of high-pressure (from over 150 to about 500 PSIG) fuel supplies and fuel systems. Since older engines have fuel systems designed for a maximum pressure of about 150 PSIG, their fuel injection systems must be completely replaced to accommodate the high-pressure fuel supply. In current upgrades to existing pipeline engines, this aspect alone frequently requires 40 man-days to accomplish.
[0008] In addition to the high material, labor, and downtime costs of installing high-pressure fuel injection systems, there are other drawbacks in terms of efficiency and performance. Known high-pressure fuel systems introduce gaseous fuel which is then choked through an orifice, valve, or pipe having constant area duct which acts as the fuel injection nozzle. In some cases, designers have suggested that the resulting gas flow velocities of Mach 0.5 to less than Mach 1.0 generate adequate mixing as a result of the turbulence created by these velocities. However, in reality, flow through these known nozzles is simply choked flow, and as such the resulting fuel jet cannot exceed the speed of sound at the outlet of the nozzle. It is well known to those skilled in the art that the best mixing occurs when the densities of two fluids to be mixed are similar. Despite this fact, natural gas injector designers have used high-pressure (about 300-500 PSIG) gaseous fuel supplies that have a density approximately five times as high as the air that has been compressed in the combustion cylinder chamber. This high density results in a high pressure “pulse” of fuel entering the cylinder without mixing as it passes though the surrounding air. Aside from the mixing problem, the high pressure pulse injects fuel at such a high rate that the injection period must be kept short to avoid too rich a mixture. This creates yet another problem, since the ideal injection period should be as long as possible to extend the interaction of fuel jet with the cylinder wall, piston, and air in the combustion chamber and to create small scale turbulence to completely mix fuel and air.
[0009] Another existing limitation which results from the application of high-pressure fuel injection involves the fact that, when dealing with compressible fluids, the sonic velocity of the fluid limits fluid flow through the nozzle. As fuel approaches sonic velocity through a choke flow orifice, a mini-shock wave is created. This shock wave effectively impedes or blocks any additional flow through the orifice, regardless of the upstream fuel pressure.
[0010] Therefore, what is needed is a low-pressure fuel injector apparatus that provides superior fuel delivery and combustion chamber mixing for more efficient combustion in gaseous-fueled engines.
SUMMARY OF THE INVENTION
[0011] The above complexities and limitations of high pressure fuel injection can be obviated by use of the present invention, which utilizes fluid dynamic principals enunciated by Laval that show that a fluid can be accelerated very efficiently, through a carefully designed converging-diverging nozzle and critical orifice, and that exit flow velocity is relative to the nozzle geometry and pressure on either side of the nozzle. This relationship for non-compressible fluids is linear and fairly straightforward. For compressible fluids, the calculations become quite onerous, but with the advent of high-speed computers, the calculations are now manageable for one skilled in the art.
[0012] The apparatus of the present invention is a fuel injector assembly having an annular nozzle with a nozzle passage that includes a converging portion, a critical orifice, and a diverging portion. The converging portion forces fuel through the critical orifice and into the diverging portion, where the fuel expands and is accelerated to a supersonic velocity. In a preferred embodiment, the critical orifice is provided as an annular gap that is created and controlled by the opening of a valve. As the valve opens to admit fuel, an annular gap is created between the circumferential edges of the poppet valve and the surrounding annular nozzle wall, the gap acting as the critical orifice. The nozzle portion below the critical orifice is a diverging nozzle that causes the expansion and acceleration of the under-expanded flow of gaseous fuel flowing through the critical orifice. Using the present invention, relatively low intake pressures of about 50 pounds per square inch gage (PSIG) and yield high-speed (sonic and supersonic) gas flow through the diverging nozzle portion for injection into the combustion chamber. Preferably, the gas flow reaches supersonic velocity, and continues to accelerate downstream of the critical section of the nozzle approaching Mach 1.5 to 2.5 on exit of the nozzle outlet. The actual final velocity of the under-expanded flow is dependent on the ratio of injection pressure and cylinder pressures, dimensions of the critical orifice and diverging nozzle portion, both in terms of diameter and length. Preferably, the diverging nozzle portion of the annular portion of the nozzle has a longitudinal axis of sufficient length so as to protrude into the combustion chamber a distance equivalent to about fifteen (15) to about fifty (50) times the width of the annular gap.
[0013] The present invention utilizes a relatively low preselected injection pressure that is always high enough to achieve supersonic injection velocity for the majority of the fuel injection event. The invention provides a converging-diverging nozzle assembly having a critical orifice formed by an annular gap, and gaseous fuel injection methods that utilize low-pressure to produce high-speed sonic and supersonic flow for direct injection of gaseous fuel into a combustion chamber of an engine. Using the present invention, relatively low fuel manifold pressures of about 50 to about 150 PSIG yield high-speed supersonic fuel flow that produces fuel jets surrounded by Mach disks and barrel shock waves from the nozzle outlet and into the combustion chamber. Preferably, the gas reaches supersonic velocity, approaching Mach 1.5 to 3.
[0014] The invention is a profiled sonic nozzle, which accelerates fuel flow to above Mach 1. As long as the pressure ratio satisfies P inj /P cyl >1.59 (for natural gas, Cp/Cv=1.31), supersonic flow can be achieved. For example, if injection pressure P inj is about 85 PSIG, cylinder pressure must not be greater than about 48 PSIG. By using this level of injection pressure, it is possible to realize supersonic flow. To create supersonic gas flow, gas dynamics theory is used to profile the nozzle area. Generally, the nozzle area will have a converging-diverging shape. For any given pressure on the nozzle inlet, there is a resulting acceleration of the flow in the diverging part of the nozzle. At the minimum area of the nozzle, the critical area, the inlet flow reaches a local maximum velocity, which is approaching or at sonic velocity. To accelerate the flow further, the nozzle profile below the critical orifice is diverging.
[0015] As described in U.S. patent application Ser. No. 09/728,425 filed Dec. 1, 2000, which application is hereby incorporated by reference, gas dynamic theory is applied to calculate the critical orifice area to provide the required fuel flow through the nozzle to produce supersonic flow at the nozzle outlet at the terminal end of the diverging nozzle portion. For example, known parameters at the nozzle inlet (pressure P inl , temperature T inl , velocity V inl ) and the critical orifice can be combined with a predetermined desired outlet velocity (Mach) to define the diverging nozzle outlet area. The ratio of local gas flow speed (V) to the speed of sound (C) (Mach number, M=V/C) in the outlet will depend on the ratio of the critical orifice area (A*) to the outlet area ratio (A out ) (AR=A*/A out ). It is recommended the correspondent area ratio (AR) be about 0.3 to about 0.4 to provide a Mach number of about 2.5 to about 3.0, although other ratios can be utilized so long as the resulting flow rate is at least Mach 1.0 or greater so that the flow at the nozzle outlet is supersonic. Depending on the pressure at the outlet, the flow may be over-expanded to create shock waves, after which the pressure will take the value of outlet pressure. In the case of over-expanded flow, the existence and configuration of shock waves produced improves the mixing by increasing entropy and creating micro-scale vortices in the shock waves. These vortices improve the mixing in a larger area and consequently make the combustion mixture more uniform.
[0016] The present invention utilizes a diverging nozzle portion disposed below at least one critical orifice to accelerate the flow of gas, thereby allowing use of lower inlet pressures above the critical orifice while still producing sonic or supersonic flow into the combustion chamber. As a result of the supersonic flow, Mach disks and barrel shock waves are created in the fuel jet exiting the diverging portion of the nozzle. When the flow passes these Mach disks and barrel shock waves, that micro-vortices are created and propagated. These micro-vortices mix the fuel with the air at the molecular level, achieving a level of mixing that is not possible using prior art gaseous fuel injection assemblies and methods.
[0017] In one embodiment of the present invention, the apparatus is a fuel injector assembly having an annular nozzle and a communicable connection to a low-pressure gaseous fuel supply. The low-pressure fuel supply is preferably natural gas at a pressure between about 50 and about 150 psig. The fuel injector includes at least one nozzle having at least one nozzle passage formed by an annular nozzle wall. The at least one nozzle has a nozzle inlet and nozzle outlet, and the nozzle passage includes a converging portion adjacent the nozzle inlet and a diverging portion adjacent the nozzle outlet. The converging and diverging portions are thus disposed between the nozzle inlet and outlet. A first critical orifice is disposed between the converging and diverging portions of the at least one nozzle passage. Valve means are provided for opening the passage to form an annular gap that acts as a first critical orifice, such that at least a portion of the fuel flow passing through the first critical orifice reaches at least sonic velocity as it travels through the diverging portion of the nozzle passage and enters the combustion chamber of an internal combustion engine. The valve means may be any known means, but is preferably a poppet valve. Preferably, the diverging nozzle portion is configured such that at least one Mach disc is created as the fuel exits the nozzle passage and enters the combustion chamber. The longitudinal axial length of the diverging portion of the annular nozzle is between about fifteen (15) to about fifty (50) times the width of the annular gap that acts as the first critical orifice. Preferably, the longitudinal axial length of the diverging portion of the annular nozzle is between about twenty-five (25) and about thirty-five (35) times the width of the annular gap.
[0018] In a second embodiment, the fuel injection assembly further comprises a sonic nozzle port in communication with the first nozzle passage, the sonic nozzle port having a nozzle inlet and nozzle outlet divided by a second critical orifice, and further having a converging portion adjacent the inlet and a diverging portion adjacent the outlet. In this embodiment, the valve means for controlling the first critical orifice simultaneously controls access to the sonic nozzle port such that at least a portion of the fuel flow passing through the first nozzle passage passes through the first critical orifice, while the remaining portion of the gas flow passes through the second critical orifice located in the sonic nozzle port, whereby flow through the assembly reaches at least sonic velocity as it travels through the diverging portion of each nozzle passage before entering the combustion chamber of an internal combustion engine.
[0019] The invention further includes methods of directly injecting natural gas or gaseous fuel into an internal combustion engine in a manner that promotes mixing of the gas with air in the combustion chamber. The methods include providing an internal combustion engine and a low-pressure fuel supply of gaseous fuel, and a fuel injection assembly communicably connecting the internal combustion engine to the low-pressure fuel supply. The fuel injection assemblies of the present invention are utilized to practice the preferred embodiments of the methods of the invention.
[0020] One advantage of the present invention is that it provides supersonic natural gas flow into a reciprocating piston internal combustion engine to promote excellent mixing with air, resulting in a cleaner burn and lower emissions in gaseous fueled engines operating at low fuel supply pressures below 150 PSIG.
[0021] Other features and advantages of the present invention will be apparent from the following more detailed description of the preferred embodiment, taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] The invention will be further understood from the following description and drawings which show a preferred embodiment of the present invention, wherein:
[0023] FIG. 1A is a partial side cross sectional view of a first embodiment of the fuel injection assembly of the present invention installed in an internal combustion engine illustrating the valve in the open position.
[0024] FIG. 1B is a partial side cross sectional view of the fuel injection assembly shown in FIG. 1A illustrating the valve in the closed position.
[0025] FIG. 2A is a partial side cross sectional view of a second embodiment of the fuel injection assembly of the present invention installed for use in an internal combustion engine, illustrating the valve in the open position.
[0026] FIG. 2C is a detailed cross-sectional view of the critical orifice of FIG. 2A , illustrating the geometry of the critical orifice formed with the valve in the open position.
[0027] FIG. 2B is a partial side cross sectional view of the fuel injection assembly shown in FIG. 2A illustrating the valve in the closed position.
[0028] FIG. 3 is a partial cross section view of the fuel injection assembly of FIG. 2A illustrating dimensions related to the sonic nozzle port.
[0029] FIGS. 4A and 4B illustrate test results of the fuel injection assembly in the embodiment of FIG. 1A installed on a gaseous-fueled internal combustion engine.
[0030] Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.
DETAILED DESCRIPTION OF THE INVENTION
[0031] The present invention relates to the injection of gaseous fuel directly into the combustion chamber of a gaseous-fueled engine, and particularly to a gaseous-fueled reciprocating piston engine. FIGS. 1A-3 illustrate several embodiments of the present invention.
[0032] In one embodiment illustrated in FIGS. 1A and 1B , a fuel injection assembly 100 includes an annular nozzle formed in the fuel injector body 102 , the nozzle having an annular wall 106 that surrounds a central nozzle passage 104 . The central nozzle passage 104 is communicably connected to a low-pressure fuel supply 130 by a fuel inlet 132 . The central passage nozzle passage 104 shown further includes a nozzle inlet 108 which connects the fuel inlet 132 to an upper flow chamber 109 . The upper flow chamber 109 shown is generally cylindrically shaped and sized so as not to impede gas flow, however, alternative configurations are contemplated to meet the particular fuel flow and pressure requirements of various engines and applications.
[0033] As shown in FIGS. 1A-1B , fuel flow through the nozzle passage 104 is controlled by a valve 118 , preferably a poppet valve 118 having a mechanism for opening and closing, such as a valve spring or hydraulic lifters. The annular nozzle wall 106 includes a converging portion 110 and a diverging portion 114 , the converging portion 110 and diverging portion 114 separated by a first critical orifice 112 . In this embodiment, the first critical orifice 112 is an annular gap created by the opening formed between the circumferential edge 122 of the valve head 120 and the annular wall 106 . Preferably, the width of the gap is between about 0.020 and 0.080 inches, and more preferably is between about 0.030 and 0.060 inches. The diverging nozzle portion 114 is disposed below the first critical orifice 112 , and terminates in a nozzle outlet 116 that protrudes through the chamber wall 142 of an internal combustion engine to provide fuel injection directly into the combustion chamber 140 . In preferred embodiments of this configuration, the diverging portion 114 has a length L that is directly proportional to the width of the gap W formed between any point on the circumferential edge 122 and the immediately surrounding annular wall 106 (as detailed in FIG. 2C ). Preferably, the length L is between about fifteen (15) to about fifty (50) times the width W. More preferably, the length L is between about twenty-five (25) and about thirty-five (35) times the width W In an alternative embodiment, the nozzle portion below the valve head 120 includes a second converging portion configured to serve as a transportation stop for the poppet valve 118 when the valve 118 is in the open position, or to prevent excessive valve travel in the event of a valve lifter failure.
[0034] In the embodiment of FIGS. 1A and 1B , fuel is introduced from a fuel supply 130 into the nozzle inlet 108 and into the nozzle passage 104 . The fuel supply is low-pressure (less than 150 PSI), preferably at between about 50 and about 150 PSI, more preferably between about 60 and about 120 PSI, and most preferably between about 60 and about 95 PSIG. The under-expanded fuel next flows into the upper flow chamber 109 before entering the converging nozzle portion 110 . As the valve 120 opens, fuel flows from the converging portion 110 through the critical orifice 112 formed between the circumferential edge 122 and the annular nozzle wall 106 . As shown in FIGS. 1A-1B , the circumferential edge 122 is profiled so as to accelerate the flow through the critical orifice 112 , such as beveling of the edge 122 . As the fuel passes through the critical orifice 112 and enters the diverging nozzle portion 114 , the fuel expands and is accelerated to a velocity in excess of sonic. The diverging portion 114 is generally cylindrical or slightly cone shaped, the length and diameter of the diverging nozzle portion 114 being dependent upon the engine geometry (bore, stroke and power) of the application, as well as the size of the critical orifice 112 . Other variables include the rate of valve lift and injection time, which may vary from engine to engine. In any embodiment, a positive pressure differential is established between nozzle inlet 108 and nozzle outlet 116 such that inlet pressure is greater than outlet pressure, causing an accelerated fuel flow through the converging nozzle portion 110 through the first critical orifice 112 at or below sonic velocity, resulting in choked flow. Upon entering the diverging nozzle portion 114 , the under-expanded flow is again accelerated, this time to speeds in excess of sonic (supersonic), as it exits the outlet 116 and enters the combustion chamber 140 . While the actual speed of the exiting flow is related to the outlet area ratio comprised of the diverging portion 114 and the combustion chamber 140 , the embodiment of FIGS. 1A-1B has been shown to accelerate the fuel flow to speeds in excess of sonic (Mach 1), to between Mach 1.5 and 2.5. This high-speed flow further produces excellent combustion chamber turbulence. In addition to the adjusting the length of the diverging portion, profiling of the diverging nozzle portion 114 , such as including a slope in the annular wall 106 at angle that further encourages the formation and propagation of sonic shock waves in the flow exiting the outlet and entering the combustion chamber. Such shock waves produce a plurality of Mach discs that produce microvortices that serve as an extremely efficient mixing mechanism for fuel and air in the combustion chamber.
[0035] A second embodiment of the fuel injection assembly is illustrated in FIGS. 2A-2B . In the second embodiment, a second critical orifice is provided below the valve by a sonic nozzle port 200 disposed in the annular wall 106 below the valve head 120 . Fuel is introduced from a fuel supply 130 into the nozzle inlet 108 and into the nozzle passage. The fuel supply is low-pressure (less than 150 PSI), preferably between about 50 and about 150 PSIG, and more preferably between about 60 and about 120 PSIG and most preferably between about 60 and about 95 PSIG. The under-expanded fuel next flows into the upper flow chamber 109 before entering a first converging nozzle portion 110 . As the valve 120 opens, fuel flows through the first critical orifice 112 formed between the valve's circumferential edge 122 and the annular nozzle wall 106 . The valve's circumferential edge 122 is preferably profiled such as by beveling of the edge 122 , so as to accelerate the flow through the annual gap that serves as the first critical orifice 112 . Some fuel flow passes through the first critical orifice 112 and expands and is accelerated out of the diverging portion outlet 116 . However, the remainder of the fuel flow passes through a sonic nozzle port 200 that includes an inlet 202 , a converging portion 204 and a diverging portion 208 separated by a second critical orifice 206 , and terminating in an outlet 210 that is in direct communication with the combustion chamber 140 . In this embodiment, the diameter of the second critical orifice 206 is approximately 30% of the inlet diameter of the converging portion 204 . The converging 204 and diverging portion 208 are generally conical, the length and diameter of the diverging nozzle portion 208 being dependent upon the engine geometry (bore, stroke and power) of the application, fuel type, as well as the size of the second critical orifice 206 .
[0036] Entry of gas flow into the sonic nozzle port 200 provided in this second embodiment is controlled by the valve 120 . As illustrated in FIG. 2A , as the valve 118 opens, the valve head 120 opens and fuel enters the sonic port 200 though an inlet 202 that has a converging section 204 communicably connected to a central port passage. The central port passage comprises a diverging section 208 that terminates in an outlet 210 that is in direct communication with the combustion chamber 140 of a reciprocating piston engine. Fuel flowing into the inlet 202 enters the narrowing diameter of the converging section 204 , and passes through the critical orifice 206 , and is accelerated as it expands upon entering the diverging section 208 . Fuel continues to expand in the diverging section 208 , and flow becomes accelerated to supersonic velocity as the fuel exits the outlet 210 and enters the combustion chamber 140 .
[0037] In the embodiment of FIGS. 2A-2B , a positive pressure differential is established between nozzle inlet 108 and nozzle outlets 116 and 210 such that inlet pressure is greater than outlet pressure, causing an accelerated fuel flow through the converging nozzle through the critical orifices 116 , 206 below sonic velocity, resulting in choked flow. Upon entering the diverging nozzle portions 114 , 208 , the under-expanded flow is again accelerated, this time to speeds in excess of sonic. While the actual speed of the exiting flow is related to the outlet area ratios comprised of the diverging portions 114 , 208 and the combustion chamber 140 , the embodiment of FIGS. 2A-2B has been shown to accelerate the fuel flow to speeds in excess of sonic (Mach 1), to between Mach 1.5 and 2.5 when the positive pressure differential factor, P inj /P cyl , is at least 1.59. This high-speed flow further produces excellent combustion chamber turbulence. Additionally, profiling of the diverging nozzle portion, such as including a converging slope in the annular wall at angle further encourages the formation and propagation of the sonic shock waves. Such shock waves produce a plurality of Mach discs that produce microvortices that serve as an extremely efficient mixing mechanism for fuel and air in the combustion chamber.
[0038] In a preferred example, as shown in FIG. 3 , the sonic port 200 is not perfectly parallel to the diverging section 114 , but is rather disposed at an angle α offset from the extrapolated centerline A-A of the diverging section 114 , the extrapolated centerline A-A passing through the geometric center of the critical orifice. This embodiment encourages a swirling motion to the gas flowing into the combustion chamber 140 to promote mixing. Preferably, the angle α is between about 10 to about 45 degrees. Preferably, the diverging section 208 of the sonic port 200 is substantially cone shaped, and more preferably the walls of the diverging section diverge at an angle β based upon the geometric center of the inlet 202 when the valve is in the open position as illustrated in FIG. 3 . Preferably, the angle β is between 15 and 45 degrees.
[0039] The fuel injector assemblies of the present invention have been tested in natural gas internal combustion engines, and show substantial improvements in performance and efficiency over conventional injection valve assemblies currently used in the gas pipeline industry.
EXAMPLE
[0040] One example involves installation of the fuel injector assembly of FIGS. 1A-1B on a Clark TCUA internal combustion engine. As shown in FIGS. 4A and 4B with the original manufacturer's injection assembly, the engine produced oxides of Nitrogen (Nox) at a rate about 33% higher than with the first embodiment of the nozzle of the present invention. In addition, the fuel rate using the original manufacturer's injection assembly was 7450 BTU per brake horsepower hour. The original injection assembly was then replaced with the first embodiment of the nozzle assembly of the present invention having a critical orifice and diverging nozzle portion designed in accordance with the specifications of that particular engine and model, and the tests repeated. With torque, speed, ignition timing, air manifold temperature and pressure the same as baseline conditions, using the supersonic injection assembly, the NOx emissions were 33% lower per Brake horsepower-hour, and the fuel rate was 7415 BTU per brake horsepower-hour, an improvement of 35 BTU. Carbon monoxide (CO) emissions were also monitored, although such emissions are a secondary pollution consideration as compared to Nox emissions. The combustion stability also improved, as evidenced by an observed reduction in peak cylinder pressure variations from cycle to cycle.
[0041] By way of non-limiting example, the supersonic gaseous fuel injector assemblies of the present invention can also be installed on factory specification or modified engines such as Cooper V-250, Cooper GMW, Cooper GMV, Clark TCV, Clark TCVD, Clark TLAD, and others. While these exemplary engines are used in gas pipeline applications, the present invention is applicable to any gaseous fuel injection application involving internal combustion engines, including but not limited to natural gas powered locomotives, marine vessels, automobiles, trucks, aircraft, electrical power generators, and the like.
[0042] In alternate embodiments based upon the embodiments of FIGS. 2A-2B , the diverging portion 114 of the nozzle wall 106 may further include a plurality of ports similar to port 200 that allow a portion of the fuel flow to enter the combustion chamber 140 without passing through the nozzle outlet 116 . Preferably, the ports are angled so that the fuel flow is generally directed downward toward the combustion chamber 140 , thereby encouraging the swirling of fuel flowing from these ports as well as the open end of the nozzle. The holes may be at any angle, but are preferably generally substantially parallel to the motion of the diverging portion 114 piston). However, most preferably, the ports are not perfectly parallel to the main nozzle passage 104 and to each other, but are offset at angles so as to impart a swirl to the collective fuel flow. This addition of an angular flow vector to any of the above embodiments further enhances the mixing of air and fuel in the combustion chamber. Ports may appear in the form of internal porting, fins, or other known means to impart angular flow vectors. The angular momentum imparted in the compressible fuel is conserved through the expansion process and will increase the mixing of the fuel and air.
[0043] While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.
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This invention relates to the injection of compressible gaseous fuel directly into the combustion chamber of a reciprocating piston-type internal combustion engine. In particular, the invention provides apparatus and methods for low-pressure, high-speed direct injection of compressed natural gas into a combustion chamber of an engine. Using the present invention, relatively low intake pressures of about 50 to about 150 PSIG yield high-speed (sonic and supersonic) gas flow through the diverging nozzle portion for injection into the combustion chamber. Preferably, the gas reaches supersonic velocity, approaching Mach 1.5 to 2.5.
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BACKGROUND OF THE INVENTION
This invention relates to an arrangement for recording an information signal on a magnetic record carrier, comprising a write head for recording information on the record carrier, and a write amplifier for driving the write head in response to the information signal, the write amplifier comprising:
a first write terminal, and a second write terminal, which are coupled to the write head;
a first supply terminal and a second supply terminal for the connection of a supply voltage for the write amplifier;
a first current mirror having a first current input terminal, a first current output terminal coupled to the first write terminal, and a first common current terminal connected to the first supply terminal;
a second current mirror having a second current input terminal, a second current output terminal coupled to the second write terminal, and a second common current terminal connected to the first supply terminal; and
current switching means for establishing a current path between the first current output terminal and the second supply terminal via the first write terminal and the second write terminal for a first value of the information signal and for establishing a current path between the second current output terminal and the second supply terminal via the first write terminal and the second write terminal for a second value of the information signal.
The invention also relates to a write amplifier for use in such an arrangement.
Such an arrangement and write amplifier are known from U.S. Pat. No. 5,282,094, FIG. 1. Write amplifiers having inductive write heads are used, inter alia, in hard disk drives for the storage of digital information signals, the polarity of the write current through the write head being reversed in response to the bit pattern of the information signal. In the known arrangement polarity reversal is effected with current switching means which establish a low-impedance connection between one of the write terminals and the second supply terminal. The other write terminal is then connected to the high-impedance current output terminal of the first or the second current mirror. As a result, the common-mode voltage across the write head does not have a fixed value and depends on the number of ones or zeros of the preceding bit pattern of the information signal. Consequently, the following bit change is influenced by the common-mode voltage just before the change, which may give rise to bit-pattern-dependent signal distortion. Moreover, the fluctuating common-mode voltage may produce crosstalk to other sensitive circuits. These problems limit the bit rate of the information signal to be recorded.
SUMMARY OF THE INVENTION
It is one of the objects of the invention to provide an arrangement having a write amplifier whose structure makes it more suitable for high bit rates. To this end, in accordance with the invention, the arrangement of the type defined in the opening paragraph is characterized in that the current switching means comprise:
a third current mirror having a third current input terminal, a third current output terminal coupled to the first write terminal, and a third common current terminal connected to the second supply terminal;
a fourth current mirror having a fourth current input terminal, a fourth current output terminal coupled to the second write terminal, and a fourth common current terminal connected to the second supply terminal;
a first switchable current source connected between the first current input terminal and the fourth current input terminal for supplying a first current for a first value of the information signal; and
a second switchable current source connected between the second current input terminal and the third current input terminal for supplying a second current for the second value of the information signal.
The write head is now connected between the high-impedance outputs of four current mirrors, which are turned on two at a time by means of the switchable current sources. When the first switchable current source conducts, a current will flow through the write head from the first supply terminal to the second supply terminal via the first and the fourth current mirror. When the second switchable current, source conducts, an opposite current will flow through the write head from the first supply terminal to the second supply terminal via the second and the third current mirror. Since the write head is connected between the high-impedance current output terminals of the four current mirrors the common-mode voltage can be fixed as required by additional measures, preferably at half the supply voltage, and can be rendered independent of the bit pattern. The current mirrors then saturate only during the peaks of the write head voltage and no clamping circuits are needed to preclude oversaturation of the output transistors of the write amplifier.
A first-embodiment of an arrangement in accordance with the invention with common-mode control is characterized in that the write amplifier further comprises: a first resistor connected between the first write terminal and a first node, a second resistor connected between the first node and the second write terminal, a third resistor connected between the first supply terminal and the first node, and a fourth resistor connected between the second supply terminal and the first node. The first and the second resistor are arranged in series across the write head and also form damping resistors for the write head. The common-mode voltage across the write head is equal to the voltage on the first node, which forms the center tap of the first and the second resistor, and is fixed by means of a simple voltage divider arranged across the power supply and comprising the third and the fourth resistor. The fixation of the common-mode voltage improves as the impedance of the voltage divider is reduced. Too low an impedance is to be avoided in view of the increasing dissipation in the voltage divider.
In order to reduce the dissipation, a second embodiment of the arrangement in accordance with the invention is characterized in that the write amplifier further comprises: a first resistor connected between the first write terminal and a first node, a second resistor connected between the first node and the second write terminal, a first transistor of a first conductivity type having a control electrode, a first main electrode connected to the first node and a second main electrode coupled to the first supply terminal, a second transistor of the first conductivity type having a control electrode connected to the control electrode of the first transistor, a first main electrode, and a second main electrode connected to the control electrode of the second transistor, a third resistor connected between the first supply terminal and the second main electrode of the second transistor, a third transistor of a second conductivity type having a control electrode, a first main electrode connected to the first node and a second main electrode coupled to the second supply terminal, a fourth transistor of the second conductivity type having a control electrode connected to the control electrode of the third transistor, a first main electrode connected to the first main electrode of the second transistor and a second main electrode connected to the control electrode of the fourth transistor, and a fourth resistor connected between the second supply terminal and the second main electrode of the fourth transistor.
The first and the second transistor operate in class A/B and produce at the first node a low impedance, which can be realized with comparatively larger third and fourth resistors.
It is to be noted that the transistors may be bipolar transistors or unipolar MOS transistors. The control electrode, the first main electrode and the second main electrode correspond to the base, the emitter and the collector, respectively, for a bipolar transistor and to the gate, the source and the drain, respectively, for a unipolar transistor.
Only two of the four current mirrors are active at the same time. The turn-on of the current mirrors can be speeded up by allowing a quiescent current to flow through the four current mirrors. Then, less current is needed to charge and discharge the stray capacitances in the current mirrors. A third embodiment of an arrangement with common mode control in accordance with the invention is characterized in that the write amplifier further comprises:
a first resistor connected between the first write terminal and a first node, a second resistor connected between the first node and the second write terminal, a third resistor connected between the first write terminal and a second node, a fourth resistor connected between the second node and the second write terminal,
a first transistor of a first conductivity type having a control electrode, a first main electrode connected to the first node and a second main electrode coupled to the first supply terminal,
a second transistor of the first conductivity type having a control electrode connected to the control electrode of the first transistor, a first main electrode, and a second main electrode connected to the control electrode of the second transistor, a fifth resistor connected between the first supply terminal and the second main electrode of the second transistor,
a third transistor of the first conductivity type having a control electrode connected to the control electrode of the first transistor, a first main electrode connected to the first node and a second main electrode coupled to the second supply terminal,
a fourth transistor of a second conductivity type having a control electrode, a first main electrode connected to the first node and a second main electrode coupled to one of the third current input terminal and the fourth current input terminal, a fifth transistor of the second conductivity type having a control electrode connected to the control electrode of the fourth transistor, a first main electrode connected to the first main electrode of the second transistor and a second main electrode connected to the control electrode of the fifth transistor, a sixth resistor connected between the second supply terminal and the second main electrode of the fifth transistor,
a sixth transistor of the second conductivity type having a control electrode connected to the control electrode of the fourth transistor, a first main electrode connected to the second node and a second main electrode coupled to the other one of the third current the quiescent current input terminal and the fourth current input terminal.
This embodiment advantageously combines the common-mode control and the quiescent current setting for the four current mirrors. Now the bias currents through the four transistors connected to the first and the second node are not drained to the supply terminals but flow into the respective current input terminals of the four current mirrors and serve as quiescent currents for the current mirrors. The damping resistance is made up of two series chains of two resistors having a center tap at the first and the second node. The current mirrors reduce the apparent resistance of the damping resistors for common-mode signals by a factor determined by the current gain of the current mirrors. The individual series chains function as emitter degeneration resistors for the first and the fourth transistor, whose emitters are connected to the first node, and for the third and the sixth transistor, whose emitters are connected to the second node. This reduces the influence of a possible mismatch between the first and the third transistor and between the fourth and the sixth transistor. An alternative embodiment is characterized in that the second node is connected to the first node.
The afore-mentioned first and second switchable current sources determine how much and in which direction current flows through the write head. In this respect an embodiment of the arrangement in accordance with the invention is characterized in that the first and the second switchable current source comprise:
a seventh transistor of a first conductivity type having a control electrode connected to a third node, a first main electrode, and a second main electrode coupled to the first current input terminal,
an eighth transistor of the first conductivity type having a control electrode connected to the control electrode of the seventh transistor, a first main electrode, and a second main electrode coupled to the first supply terminal,
a ninth transistor of a second conductivity type having a control electrode connected to a fourth node, a first main electrode connected to the first main electrode of the seventh transistor, and a second main electrode coupled to the fourth current input terminal, a diode-connected tenth transistor of the second conductivity type having a first main electrode connected to the first main electrode of the eighth transistor and having a control electrode and second main electrode connected to the fourth node,
a bias current source coupled to the fourth node to supply a bias current to the fourth node,
an eleventh transistor of the first conductivity type having a control electrode connected to a fifth node, a first main electrode, and a second main electrode coupled to the second current input terminal,
a twelfth transistor of the first conductivity type having a control electrode connected to the control electrode of the eleventh transistor, a first main electrode, and a second main electrode coupled to the first supply terminal, and a thirteenth transistor of the second conductivity type having a control electrode connected to the fourth node, a first main electrode connected to the first main electrode of the transistor, and a second main electrode coupled to the third current input terminal.
The bias current source determines the magnitude of the write current through the write head. The bias current is drained to the power supply via the eighth transistor or via the twelfth transistor, depending on the value of the information signal. The seventh, the ninth and the tenth transistor form a translinear loop with the eighth transistor, and the eleventh, the thirteenth and the tenth transistor form a translinear loop with the twelfth transistor. Conduction of the eighth or the twelfth transistor now results in an amplified current flowing from the first current input terminal to the third current input terminal via the seventh and the ninth transistor or from the second current input terminal to the fourth current input terminal. The d.c. level of the information signal at the third and the fifth node, applied via a suitable buffer, if required, is fully isolated from the d.c. level at the current input terminals. The switchable current sources thus form floating switchable current sources whose switching signals have d.c. levels which can be chosen freely.
The buffers for the information signal can be emitter followers or source followers. The quiescent current supply for these followers can be combined advantageously with the current supply for the switchable current sources. To this end, an embodiment of the arrangement is further characterized in that the first and the second switchable current source further comprise:
a fourteenth transistor of the first conductivity type having a control electrode for receiving the information signal, a first main electrode connected to the third node and a second main electrode coupled to the first supply terminal,
a fifteenth transistor of the first conductivity type having a control electrode for receiving the information signal, a first main electrode connected to the fifth node and a second main electrode coupled to the first supply terminal,
a sixteenth transistor of the first conductivity type having a control electrode connected to the control electrode of the eighth transistor, a first main electrode connected to the first main electrode of the eighth transistor, and a second main electrode coupled to the fifth node, a seventeenth transistor of the first conductivity type having a control electrode connected to the control electrode of the twelfth transistor, a first main electrode connected to the first main electrode of the twelfth transistor, and a second main electrode coupled to the third node, the second main electrode of the eighth transistor being connected to the third node and the second main electrode of the twelfth transistor being connected to the fifth node.
The fourteenth and the fifteenth transistor operate as signal followers and buffer the information signal. The currents through these transistors now flow to the fourth node through the eighth and the twelfth transistor, respectively. The sixteenth and the seventeenth transistor ensure that always one half of the bias current from the bias current source flows through one signal follower and the other half through the other signal follower.
Parasitic capacitances at the first and the second write terminal caused by the transistors of the write amplifier and by the wiring and construction of the write head limit the bit rate of the information signal to be recorded. This is because for high frequencies the write current is shunted by the parasitic capacitances. In order to reduce the effect of these parasitic capacitances an embodiment of the arrangement in accordance with the invention is characterised in that the write amplifier further comprises at least one of: a first capacitor connected between the first current input terminal and the second current output terminal, a second capacitor connected between the second current input terminal and the first current output terminal, a third capacitor connected between the third current input terminal and the fourth current output terminal, and a fourth capacitor connected between the fourth current input terminal and the third current output terminal.
The first to the fourth capacitor neutralize the parasitic capacitances by injecting opposite capacitive currents into the first and the second write terminal. Preferably, the capacitors are used in pairs, i.e. the first together with the second and/or the third together with the fourth capacitor, in order not to disturb the symmetry of the arrangement and not to load the common mode.
The four current mirrors may be of any suitable type. For a maximal swing of the write amplifier a preferred embodiment of the arrangement in accordance with the invention is characterized in that the third current mirror and the fourth current mirror each comprise a diode-connected input transistor of a first conductivity type having a control electrode and a second main electrode connected to the third and the fourth current input terminal, respectively, and having a first main electrode coupled to the second supply terminal, and an output transistor of the first conductivity type having a control electrode connected to the control electrode of the relevant input transistor, a first main electrode coupled to the second supply terminal, and a second main electrode connected to the third and the fourth current output terminal, and in that the first current mirror and the second current mirror each comprise a diode-connected input transistor of a second conductivity type having a control electrode and a second main electrode connected to the first and the second current input terminal, respectively, and having a first main electrode coupled to the first supply terminal, and an output transistor of the second conductivity type having a control electrode connected to the control electrode of the relevant input transistor, a first main electrode coupled to the first supply terminal, and a second main electrode connected to the first and the second current output terminal.
Current mirrors thus implemented produce a minimal voltage loss and allow an output swing up to nearly the supply voltage. Moreover, they have basically a single pole in the current transfer function, so that no additional ringing of the waveform is produced. Ringing may lead to inter-symbol interference.
This embodiment may be characterized further in that the first main electrodes of the input transistors and output transistors of the first and the second current mirror are connected to the first supply terminal via resistors, and the first main electrodes of the input transistors and output transistors of the third and the fourth current mirror are connected to the second supply terminal via resistors. The resistors provide a better matching between the current mirror transistors and improve the temperature stability.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other aspects of the invention will be described and elucidated with reference to the accompanying drawings, in which:
FIG. 1 shows a circuit diagram of an arrangement for recording an information signal on a magnetic record carrier in accordance with the invention,
FIG. 2 is a circuit diagram of an embodiment of an arrangement for recording an information signal on a magnetic record carrier in accordance with the invention,
FIG. 3 shows a first common-mode circuit for use in an arrangement in accordance with the invention,
FIG. 4 shows a second common-mode circuit for use in an arrangement in accordance with the invention,
FIG. 5 shows a circuit diagram of an embodiment of an arrangement for recording an information signal on a magnetic record carrier in accordance with the invention, including a third common-mode circuit,
FIG. 6 shows a fourth common-mode circuit for use in an arrangement in accordance with the invention,
FIG. 7 shows a first implementation of switched current sources for use in an arrangement in accordance with the invention,
FIG. 8 shows a second implementation of switched current sources for use in an arrangement in accordance with the invention, and
FIG. 9 shows a circuit diagram of an embodiment of an arrangement for recording an information signal on a magnetic record carrier in accordance with the invention, which arrangement includes neutralizing capacitors.
In these Figures like elements bear the same reference symbols.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 shows the basic structure of an arrangement for recording an information signal on a magnetic record carrier in accordance with the invention. The arrangement comprises a write head 2 for recording information on the record carrier (not shown) and a write amplifier 4 for driving the write head 2 in response to the information signal. The write amplifier has a first write terminal 6 and a second write terminal 8, which are coupled to the write head 2 to supply a write current. A first supply terminal 10 and a second supply terminal 12 serve for connection of a supply voltage for the write amplifier. In the present case the second supply terminal 12 is connected to signal ground. The amplifier 4 comprises a first current mirror 14 having a first current input terminal 16, a first current output terminal 18 coupled to the first write terminal 6, and a first common current terminal 20 connected to the first supply terminal 10; a second current mirror 22 having a second current input terminal 24, a second current output terminal 26 coupled to the second write terminal 8, and a second common current terminal 28 connected to the first supply terminal 10; a third current mirror 30 having a third current input terminal 32, a third current output terminal 34 coupled to the first write terminal 6, and a third common current terminal 36 connected to the second supply terminal 12; a fourth current mirror 38 having a fourth current input terminal 40, a fourth current output terminal 42 coupled to the second write terminal 8, and a fourth common current terminal 44 connected to the second supply terminal 12. A first switchable current source 46 is connected between the first current input terminal 16 and the fourth current input terminal 40. The first switchable current source supplies a first current for a first value of the information signal U i and is currentless for a second value of the information signal U i . The information signal U i may be, for example, the binary data signal for a disk drive or another magnetic storage medium. A second switchable current source 48 is connected between the second current input terminal 24 and the third current input terminal 32. The second switchable current source 48 receives an inverse information signal NU i and supplies a second current if the first current is zero and the other way around.
When the first switchable current source 46 is turned on current will flow from the first supply terminal 10 to the second supply terminal 12 through the first current input terminal 16 of the first current mirror 14 and through the fourth current input terminal 40 of the fourth current mirror 38. A current which is M times as large flows in the same direction from the first current output terminal 18 of the first current mirror 14 to the fourth current output terminal 42 of the fourth current mirror 38 via the first write terminal 6, the write head 2 and the second write terminal 8. Here, M is the current mirror ratio of the current mirrors 14, 22, 30 and 38. The second switchable current source 48 is turned off, so that the second current mirror 22 and the third current mirror 30 are inoperative. Now a write current flows from the first write terminal 6 to the second write terminal 8 through the write head 2.
When the first switchable current source 46 is turned off and the second 10 switchable current source 48 is turned on the second current mirror 22 and the third current mirror 30 are active and the other two current mirrors 14 and 38 are inactive. Now a write current flows in the opposite direction from the second write terminal 8 to the first write terminal 6 through the write head 2. It will be obvious that the first current of the first switchable current source 46 and the second current of the second switchable current source 48 should be equal in order to obtain equal write currents in both directions in the case were the current mirror ratios of the current mirrors are all equal.
FIG. 2 shows an embodiment in which the first current mirror 14 and the second current mirror 22 comprise bipolar PNP transistors and the third current mirror 30 and the fourth current mirror 38 comprise bipolar NPN transistors. However, it is to be noted that in the circuit arrangements disclosed and to be disclosed bipolar transistors may be replaced wholly or partly by unipolar MOS transistors. The control electrode, the first main electrode and the second main electrode correspond to the base, the emitter and the collector, respectively, for a bipolar transistor and to the gate, the source and the drain, respectively, for a unipolar transistor. The first current mirror 14 comprises a diode-connected PNP input transistor T ip1 , having its emitter connected to the first common current terminal 20 via an optional emitter resistor R ip1 and its collector to the first current input terminal 16, and a PNP output transistor T op1 , having its base connected to the base of the input transistor T ip1 , its emitter to the first common current terminal 20 via an optional emitter resistor R op1 and its collector to the first current output terminal 18. The optional emitter, resistors improve the matching of the transistors and increase the thermal stability of the current mirror. The second current mirror 22 likewise comprises PNP transistors and the third current mirror 30 and the fourth current mirror 38 likewise comprise NPN transistors, the electrodes of the respective transistors being connected to the corresponding terminals of the current mirrors.
The common-mode voltage of the write head 2 is completely indeterminate and may fluctuate with the data pattern of the information signal to be recorded. This is undesirable. The common-mode voltage should preferably lie halfway between the available output swing and should be independent of the signal content of the signal to be recorded. Since the write head 2 is arranged exclusively between high-impedance outputs of current mirrors it is possible to fix the common-mode voltage with a common-mode circuit.
FIG. 3 shows a simple common-mode circuit. A series arrangement of a first resistor 50 connected between the first write terminal 6 and a first node 52, a second resistor 54 connected between the first node 52 and the second write terminal 8, a third resistor 56 connected between the first supply terminal 10 and the first node 52, and a fourth resistor 58 connected between the second supply terminal 12 and the first node 52 is arranged in parallel with the write head. The resistors 50 and 54 also function as damping resistors for the write head. The impedance at the first node 52 is dictated by the resistors 56 and 58. For a correct fixation of the common-mode voltage a minimal impedance is desired. However, the resistance value of the resistors 56 and 58 cannot be chosen arbitrarily small on account of the increasing current through these resistors.
FIG. 4 shows a common-mode circuit which mitigates this problem. The circuit again comprises a first resistor 60 connected between the first write terminal 6 and a first node 62, and a second resistor 64 connected between the first node 62 and the second write terminal 8 and, in addition, it comprises a first NPN transistor 66 having its emitter connected to the first node 62 and having its collector coupled to the first supply terminal 10, a diode-connected second NPN transistor 68 having its base connected to the base of the first NPN transistor 66, a third resistor 70 connected between the first supply terminal 10 and the collector of the second NPN transistor 68, a first PNP transistor 72 having its emitter connected to the first node 62 and having its collector coupled to the second supply terminal 12, a diode-connected second PNP transistor 74 having its base connected to the base of the first transistor 72 and having its emitter connected to the emitter of the second NPN transistor 68, and a fourth resistor 76 connected between the second supply terminal 12 and the collector of the second PNP transistor 74.
The circuit operates in class A/B. Seen at the first node 62, the impedance is low, which provides a correct fixation of the common-mode voltage. The class A/B operation enables a small quiescent current to be obtained in and a large maximum current to be supplied by the first NPN transistor 66 or the first PNP transistor 72. The effective common-mode resistance is equal to Rd/4, the resistance value of both the resistor 60 and the resistor 64 being equal to Rd/2. The overall damping resistance across the write head 2 is consequently Rd.
In order to step up the switching speed of the current mirrors in the arrangements shown in FIGS. 1 and 2 it is desirable to have a quiescent current in the current mirrors. This quiescent current setting and the common-mode circuit can be combined advantageously. FIG. 5 shows an embodiment in which this is implemented. The write amplifier 4 again comprises four current mirrors 14, 22, 30 and 38, the write head 2, the first switchable current source 46 and the second switchable current source 48 as shown in FIG. 1. The common-mode circuit comprises a first resistor 78 connected between the first write terminal 6 and a first node 80, a second resistor 82 between a second node 84 and the second write terminal 8, a first transistor 86 of the NPN type having its emitter connected to the first node 80 and having its collector coupled to the first current input terminal 16, a diode-connected second transistor 88 of the NPN type having its base connected to the base of the first transistor 86, a third resistor 90 connected between the first supply terminal 10 and the collector of the second transistor 88, and a third transistor 92 of the NPN type having its base connected to the base of the first transistor 86 and its emitter to the second node 84 and having its collector coupled to the second current input terminal 24. The common-mode circuit further comprises a fourth transistor 94 of the PNP type having its emitter connected to the first node 80 and having its collector coupled to the third current input terminal 32, a diode-connected fifth transistor 96 of the PNP type having its base connected to the base of the fourth transistor 94 and having its emitter connected to the emitter of the second transistor 88, a fourth resistor 98 connected between the second supply terminal 12 and the collector of the fifth transistor 96, and a sixth transistor 100 of the PNP type having its base connected to the base of the fourth transistor 94 and its emitter to the second node 84 and having its collector coupled to the fourth current input terminal 40. The first node 80 and the second node 84 are interconnected. The quiescent current which flows through the transistors 86 and 94 now also flows into the first current input terminal 16 of the first current mirror 14 and into the third current input terminal 32 of the third current mirror 30. The quiescent current setting for the second current mirror 22 and the fourth current mirror 38 is obtained in a similar way by means of the transistors 92 and 100. The effective common-mode resistance is equal to Rd/(4(M+1)), where Rd/2 is the resistance value of the first resistor 78 and of the second resistor 82 and M is the current mirror ratio of the current mirrors 14, 22, 30 and 38. A voltage variation at the write terminal 6 produces in the first resistor 78 a current which appears M times as large at the same write terminal 6. The apparent resistance value Rd/2 of the first resistor 78 is thus reduced by a factor (M+1). The same occurs for the second resistor 82. It is to be noted that the collector of the transistor 94 may be coupled to the fourth current input terminal 40 instead of to the third current input terminal 32 and that the collector of the transistor 100 may be coupled to the third current input terminal 32 instead of to the fourth current input terminal 40. This makes no difference for the quiescent current setting because the current in the transistors 94 and 100 is the same. If desired, instead of the transistors 94 and 100, the collectors of the transistors 86 and 92 may be connected crosswise to the current input terminal 16 and 24.
FIG. 6 shows an alternative solution, in which the connection between the first node 80 and the second node 84 is severed. Instead of this, a fifth resistor 102 is now connected between the write terminal 6 and the second node 84 and a sixth resistor 104 between the first node 80 and the write terminal 8. This solution can be more accurate because the transistors 86 and 92 as well as the transistors 94 and 100 now each see a separate degeneration resistor in series with their emitters. This mitigates the effect of a possible mismatch between the transistors 86 and 92 and between the transistors 94 and 100. Again, it is to be noted that the collector of the transistor 94 may be coupled to the fourth current input terminal 40 instead of to the third current input terminal 32 and that the collector of the transistor 100 may be coupled to the third current input terminal 32 instead of to the fourth current input terminal 40.
FIG. 7 shows a circuit diagram of an implementation of the first switchable current source 46 and the second switchable current source 48 of the arrangements shown in FIGS. 1, 2 and 5. The two switchable current sources are united in one circuit comprising the following elements. An NPN transistor 106 having its base connected to a third node 108 and having its collector coupled to the first current input terminal 16, an NPN transistor 110 having its base connected to the base of the transistor 106 and having its collector coupled to the first supply terminal 10, a PNP transistor 112 having its base connected to a fourth node 114 and its emitter to the emitter of the transistor 106 and having its collector coupled to the fourth current input terminal 40, a diode-connected PNP transistor 116 having its emitter connected to the emitter of the transistor 110 and having its base and its collector connected to the fourth node 114, a bias current source 118 coupled to the fourth node 114 to supply a bias current I c to the fourth node 114. The circuit further comprises an NPN transistor 120 having its base connected to a fifth node 122 and having its collector coupled to the second current input terminal 24, an NPN transistor 124 having its base connected to the base of the transistor 120 and having its collector coupled to the first supply terminal 10, and a PNP transistor 126 having its base connected to the fourth node 114 and its emitter to the emitter of the transistor 120 and having its collector coupled to the third current input terminal 32.
The nodes 108 and 122 are driven in phase opposition with the information signal U i and the inverse information signal NU i via buffers 128 and 130. When the voltage at the node 108 is high and the voltage at the node 122 is low the transistor 110 is conductive and the transistor 124 is cut off. The bias current I c of the bias current source 118 flows wholly through the transistor 110 via the transistor 116. The base-emitter junctions of the transistors 106, 110, 116 and 112 form a translinear loop, the sum of the base-emitter voltages of the transistors 106 and 112 being equal to the sum of the base-emitter voltages of the transistors 110 and 116. By means of the well-known formula for the relationship between the collector current and the base-emitter voltage of a transistor it is then possible to derive that the current I through the transistors 106 and 112 is equal to I=SQRT (M*N)*I c , where SQRT is the root function, M the ratio between the emitter areas of the transistors 106 and 110 and N the ratio between the emitter areas of the transistors 112 and 116. As a result of this, a current I will flow between the terminals 16 and 40, whose magnitude is proportional to the current I c , the proportionality factor being determined by the geometries of the transistors 106, 110, 112 and 116.
Likewise, a current will flow between the second current input terminal 24 and the third current input terminal 32 if the voltage at the node 122 is high and that at the node 108 is low. To this end, the bias current source 118 is preferably an adjustable or programmable current source, for example, an IDAC (digital-to-analog converter with current output). Since the current input terminals 16, 24, 32 and 40 are all coupled to collectors the d.c. level of the information signals U i and NU i is now isolated from the d.c. levels of the current input terminals of the current mirrors of the write amplifier. Thus, the switched current sources 46 and 48 are floating relative to the supply voltages at the first supply terminal 10 and the second supply terminal 12.
The buffers 128 and 130 may comprise emitter-followers with emitter current sources. However, saving current is possible by using the currents through the transistors 110 and 124 for this purpose. FIG. 8 shows how this can be realized. The buffer 128 is now an NPN emitter-follower 132 whose base receives an amplified information signal, whose emitter is connected to the third node 108 and whose collector is coupled to the first supply terminal 10. The collector of the transistor 110 is connected to the emitter of the emitter-follower 132. The buffer 130 likewise comprises an NPN emitter-follower 134 whose base receives an amplified inverse information signal, whose emitter is connected to the fifth node 122 and whose collector is coupled to the first supply terminal 10. The collector of the transistor 124 is connected to the emitter of the emitter-follower 134. The collector currents of the transistors 110 and 124 consequently also flow through the emitter-followers 132 and 134, respectively. Furthermore, there is provided an NPN transistor 136 having its base connected to the base of the transistor 110 and its emitter to the emitter of the transistor 110 and having its collector coupled to the fifth node 122, and an NPN transistor 138 having its base connected to the base of the transistor 124 and its emitter to the emitter of the transistor 124 and having its collector coupled to the third node 108. The transistors 136 and 138 ensure that the currents through the emitter-followers 132 and 134 cannot become zero if one of the transistors 110 and 124 is cut off. Thus, each of the two emitter-followers always receives half the bias current I c if the geometries of the transistors 110, 136, 138 and 124 are selected to be equal.
The bases of the emitter-followers 132 and 134 are driven, by way of example, by the transistors of a differential pair 140 whose bases are arranged to receive the complementary information signals U i and NU i , which are supplied, for example, by a data flip-flop.
FIG. 9 again shows the arrangement of FIG. 2 but now without the write head 2 and the emitter resistors in the current mirrors. A number of parasitic capacitances are shown, i.e. one having a value C cwp between collector and well of the PNP output transistors T op1 and T op2 , one having a value C csn between collector and substrate of the NPN output transistors T on3 and T on4 , one having a value C cbp between collector and base of the PNP output transistors T op1 and T op2 , and one having a value C cbn between collector and base of the NPN output transistors T on3 and T on4 . All these parasitic capacitances have an effect on the write current through the write terminals 6 and 8. The effect is that at high frequencies the write current flows through the parasitic capacitances instead of through the write head. This effect limits the bit rate of the write current. In order to reduce or even eliminate the adverse effect of the parasitic capacitances four neutralising capacitors 142, 144, 146 and 148 are provided, whose capacitance values are C np , C nn and C nn , respectively. The capacitor 142 is connected between the first current input terminal 16 and the second current output terminal 26, the second capacitor 144 between the second current input terminal 24 and the first current output terminal 18, the third capacitor 146 between the third current input terminal 32 and the fourth current output terminal 42, and the fourth capacitor 148 between the fourth current input terminal 40 and the third current output terminal.
When it is assumed that the current mirror ratio of the four current mirrors 14, 22, 30 and 38 is M the capacitance value C h seen between the write terminal 6 and the write terminal 8 will be equal to:
C.sub.h =(C.sub.cwp +C.sub.csn +(1+M)(C.sub.cbp +C.sub.cbn)+(1-M)(C.sub.np +C.sub.nn))/2
This may be illustrated as follows by determining which currents flow in, for example, the third current output terminal 34 as a result of the capacitors connected to this terminal. If the voltage at the third current output terminal 34 is assumed to be V, the voltage at the fourth current output terminal 42 will be -V. The current i in the third current output terminal 34 is then:
i=p*V*C.sub.csn +p*V*C.sub.cbn +p*V*C.sub.nn +M*{p*V*C.sub.cbn -p*V*C.sub.nn }=p*V*{C.sub.csn +(M+1)C.sub.cbn -(M-1)C.sub.nn }
The current through the capacitor 146 has an opposite sign and is enlarged by the current mirror factor M. A similar calculation applies to the other current output terminals.
With M=5, C cwp +C csn =6 pF and C cbp +C cbn =4 pF C h will be 15 pF without neutralization and 5 pF with neutralization, assuming that C np +C nn =5 pF. This yields an improvement by a factor of 3. Obviously, it is also possible to neutralise the parasitic capacitance of the write head itself by making the neutralizing capacitors sufficiently large.
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An apparatus for recording on a magnetic record carrier includes a write amplifier comprising four current mirrors which are turned on two at a time by two switchable floating current sources connected between the input terminals of the current mirrors in order to produce a write current of alternating polarity through a write head. The high impedance at the terminals of the write head enables the common-mode voltage across the write head to be fixed at any desired voltage value by means of a common-mode circuit. The symmetrical structure further enables the parasitic capacitances at the write terminals to be neutralized by means of neutralizing capacitors.
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This invention relates to new chemical compounds and their use in medicine. In particular the invention concerns novel dimeric compounds, methods for their preparation, pharmaceutical formulations thereof and their use as anti-viral agents.
BACKGROUND OF THE INVENTION
Enzymes with the ability to cleave N-acetyl neuraminic acid (NANA), also known as sialic acid, from other carbohydrates are present in many microorganisms. These include bacteria such as Vibrio cholerae, Clostridium perfringens, Streptococcus pneumoniae and Arthrobacter sialophilus , and viruses such as influenza virus, parainfluenza virus, mumps virus, Newcastle disease virus and Sendai virus. Most of these viruses are of the orthomyxovirus or paramyxovirus groups, and carry a neuraminidase activity on the surface of the virus particles. Many of these neuraminidase-possessing organisms are major pathogens of man and/or animals, and some, such as influenza virus and Newcastle disease virus, cause diseases of enormous importance.
It has long been thought that inhibitors of neuraminidase might prevent infection by neuraminidase-bearing viruses. Most of the known neuraminidase inhibitors are analogues of neuraminic acid, such as 2-deoxy-2,3-dehydro-N-acetylneuraminic acid (DANA) and some of its derivatives (Meindl et al, Virology, 1974 58 457). Our International Patent Publication No. WO 91/16320 describes a number of analogues of DANA which are active against viral neuraminidase, and it has been shown in particular that 4-guanidino-2-deoxy-2,3-dehydro-N-acetylneuraminic acid (Compound (A), code number GG167) is useful in the treatment of influenza A and B (N. Engl. J. Med., 1997 337 874–880). Other patent applications describe various closely-related sialic acid derivatives (eg. PCT Publications No. WO 95/18800, No. WO 95/20583 and No. WO 98/06712), and anti-viral macromolecular conjugates of GG167 have also been described (International Patent Application No. PCT/AU97/00771).
International Patent Publication No. WO 00/55149, describes dimeric compounds which comprise two neuraminidase binding molecules, such as compound (A), attached to a common spacer or linking group of up to 100 atoms in length.
We have now discovered a novel class of compounds which fall within the generic scope of International Patent Publication No. WO 00/55149, but which are not specifically disclosed therein, and exhibit a surprisingly advantageous anti-influenza activity profile which includes an enhanced lung residency time and high potency.
Without wishing to be bound by theory, the basis for the long residency time in the lungs is thought to be due to the size and molecular weight of the compounds preventing entry through tight junctions in the respiratory epithelium and the polarity of the compounds being such that passage through the cell membranes occurs very inefficiently. An alternative theory is that the compounds themselves interact with the phospholipids in the cell membrane or other components of the respiratory epithelium and increase the residency time in the lungs.
SUMMARY OF THE INVENTION
In a first aspect, the present invention provides for a compound of general formula (I):
in which
R is an amino or guanidino group;
R 2 is acetyl or trifluoroacetyl; and
n is an integer from 10 to 18
or a pharmaceutically acceptable derivative thereof.
Preferably R is a guanidino group.
Preferably R 2 is an acetyl group.
Preferably n is 10 to 14, most preferably 12 to 14.
It will be appreciated by those skilled in the art that the compounds of formula (I) may be modified to provide pharmaceutically acceptable derivatives thereof at any one or more of the functional groups in the compounds of formula (I). Of particular interest as such derivatives are compounds modified at the carboxyl function, hydroxyl functions or at amino groups. Thus compounds of interest include alkyl esters, such as methyl, ethyl, propyl or isopropyl esters, aryl esters, such as phenyl, benzoyl esters, and acetyl esters of the compounds of formula (I).
The term “pharmaceutically acceptable derivative” means any pharmaceutically acceptable salt, ether, ester or salt of such ester of a compound of formula (I) or any other compound which, upon administration to the recipient, is capable of providing a compound of formula (I) or an anti-virally active metabolite or residue thereof. Of particular interest as derivatives are compounds modified at the sialic acid carboxy or glycerol hydroxy groups, or at amino and guanidine groups.
Pharmaceutically acceptable salts of the compounds of formula (I) include those derived from pharmaceutically acceptable inorganic and organic acids and bases. Examples of suitable acids include hydrochloric, hydrobromic, sulphuric, nitric, perchloric, fumaric, maleic, phosphoric, glycollic, lactic, salicylic, succinic, toluene-p-sulphonic, tartaric, acetic, citric, methanesulphonic, formic, benzoic, malonic, naphthalene-2-sulphonic and benzenesulphonic acids. Other acids such as oxalic acid, while not in themselves pharmaceutically acceptable, may be useful in the preparation of salts useful as intermediates in obtaining compounds of the invention and their pharmaceutically acceptable acid addition salts.
Salts derived from appropriate bases include alkali metal (eg. sodium), alkaline earth metal (eg. magnesium), ammonium, and NR 4 + (where R is C 1-4 alkyl) salts.
The compounds of the invention may be prepared by methods described herein. It will be apparent to those skilled in the art, that it is necessary to use protecting groups to protect one or more functional groups of the neuraminidase binding molecule during the process of attaching the monomers to the alkyl spacer group. See for example “Protective Groups in Organic Synthesis” by T. W. Green and P. G. M. Nuts (John Wiley & Sons, 1991). Pharmaceutically acceptable salts of the compounds of formula (I) may be prepared according to known procedures.
Accordingly, the present invention also provides a method for the preparation of the compound of formula (I), which comprises the step of deprotection of a compound of formula (II)
in which n is as defined above, P 1 is a carboxylic acid protecting group and P 2 is an amine protecting group.
The present invention further provides a method for the preparation of the compound of formula (I), which comprises the steps of:
(a) reacting a compound of formula (III)
in which P 1 and P 2 are as defined above, with a compound of formula (IV):
OCN(CH 2 ) n NCO (IV)
in which n is as defined above to form the compound of formula (II) as defined above; and
(b) deprotection of the compound of formula (II).
The present invention still further provides a method for the preparation of the compound of formula (I) which comprises the steps of:
(a) protecting a compound of formula (V)
in which P 1 and P 2 are as defined above to form the compound of formula (III) as defined above;
(b) reacting the compound of formula (III) with the compound of formula (IV) as defined above to form the compound of formula (II) as defined above; and
(c) deprotection of the compound of formula (II).
For use in therapy it is preferable that the compounds of formula (I) are in crystalline form. We have found that the compound of formula (I) in which R is a guanidino group, R 2 is an acetyl group and n is 13 (Example 4 below) can be prepared in crystalline form by crystallisation from aqueous solution by procedures described herein.
The compounds of formula (I) possess antiviral activity. In particular these compounds are inhibitors of viral neuraminidase of orthomyxoviruses and paramyxoviruses, for example the viral neuraminidase of influenza A and B, parainfluenza, mumps and Newcastle disease.
Thus in a second aspect the invention provides a compound of formula (I) or a pharmaceutically acceptable derivative thereof, for use as an active therapeutic agent in the treatment of a viral infection, for example orthomyxovirus and paramyxovirus infections.
In a third aspect the invention provides a method for the prevention or treatment of a viral infection comprising the step of administration to a subject in need thereof of an effective amount of a compound of formula (I), or a pharmaceutically acceptable salt or derivative thereof.
Preferably, the viral infection is an orthomyxovirus or paramyxovirus infection. More preferably the viral infection is an influenza A or B infection.
Preferably the subject is an animal such as a mammal, more preferably a human, or a member of the genus Equus , for example a horse, donkey or mule. Most preferably the mammal is a human.
In a fourth aspect the invention provides use of a compound of the invention for the manufacture of a medicament for the treatment of a viral infection.
As used herein, the term “effective amount” is meant an amount of the compound of formula I effective to preventing or treating a viral infection in order to yield a desired therapeutic response. For example, to overcome or alleviate the effects of a viral infection.
The term “therapeutically-effective amount” means an amount of the compound of formula I to yield a desired therapeutic response. For example, treating or preventing a viral infection.
The specific “therapeutically-effective amount” will, obviously, vary with such factors as the particular viral infection being treated, the physical condition of the subject, the type of animal being treated, the duration of the treatment, the nature of concurrent therapy (if any), and the specific formulation employed and the structure of the compound or its derivatives.
Generally, the terms “treating”, “treatment” and the like are used herein to mean affecting a subject, tissue or cell to obtain a desired pharmacologic and/or physiologic effect. The effect may be prophylactic in terms of completely or partially preventing a viral infection or sign or symptom thereof, and/or may be therapeutic in terms of a partial or complete cure of a viral infection. “Treating” as used herein covers any treatment of, or prevention of a viral infection in a vertebrate, a mammal, particularly a human, and includes: (a) preventing the viral infection from occurring in a subject that may be predisposed to the viral infection, but has not yet been diagnosed to the viral infection, but has not yet been diagnosed as having it; (b) inhibiting the viral infection, ie., arresting its development; or (c) relieving or ameliorating the effects, i.e., cause regression of the symptoms of the viral infection.
The compounds of the invention may also be used in diagnostic methods, in particular methods for the detection of influenza virus. For use in such methods it may be advantageous to link a compound of the invention to a label, such as a radioactive, fluorescent or chemiluminescent label.
Methods of diagnosis for which the compounds of the invention are suitable are described, for example, in our earlier applications PCT/AU97/00109 and PCT/AU97/00771.
In a fifth aspect the invention provides a method for the detection of a viral infection which comprises the step of contacting the compound of the invention with a sample suspected of containing the virus.
It will be further appreciated that the amount of a compound of the invention required for use in treatment will vary not only with the particular compound selected but also with the route of administration, the nature of the condition being treated, and the age and condition of the patient, and will ultimately be at the discretion of the attendant physician or veterinarian. In general however, a suitable dose will be in the range of from about 0.001 to 100 mg/kg of bodyweight per day, preferably in the range of 0.01 to 10 mg/kg/day, most preferably in the range of 0.1 to 1 mg/kg/day.
Treatment is preferably commenced before or at the time of infection and continued until virus is no longer present in the respiratory tract. However the compounds are also effective when given post-infection, for example after the appearance of established symptoms.
Suitably treatment is given on one or two occasions, preferably only once only for treatment, and preferably once per week for prophylaxis.
The compound is conveniently administered in unit dosage form, for example containing 1 to 100 mg, more conveniently 1 to 20 mg of active ingredient per unit dosage form.
While it is possible that, for use in therapy, a compound of the invention may be administered as the raw chemical, it is preferable to present the active ingredient as a pharmaceutical formulation.
Thus in a sixth aspect the invention provides a pharmaceutical formulation comprising a compound of formula (I) or a pharmaceutically acceptable salt or derivative thereof, together with one or more pharmaceutically acceptable carriers therefor and, optionally, other therapeutic and/or prophylactic ingredients. The carrier(s) must be “acceptable” in the sense of being compatible with the other ingredients of the formulation and not being deleterious to the recipient thereof.
The compounds of the invention may also be used in combination with other therapeutic and/or prophylactic agents, for example other anti-infective agents. In particular the compounds of the invention may be employed with other antiviral agents. The invention thus provides in a seventh aspect a combination comprising a compound of formula (I) or a pharmaceutically acceptable salt or derivative thereof together with another therapeutically and/or prophylactically active agent, in particular an antiviral agent.
The combinations referred to above may conveniently be presented for use in the form of a pharmaceutical formulation and thus such formulations comprising a combination as defined above together with a pharmaceutically acceptable carrier therefor comprise a further aspect of the invention.
Suitable therapeutic and/or prophylactic agents for use in such combinations include other anti-infective agents, in particular anti-bacterial and anti-viral agents such as those used to treat respiratory infections. For example, other compounds or vaccines effective against influenza viruses, such as the sialic acid analogues referred to above, e.g. zanamivir, oseltamivir, amantadine, rimantadine and ribavirin and FluVax, may be included in such combinations.
The individual components of such combinations may be administered either separately, sequentially or simultaneously in separate or combined pharmaceutical formulations.
When the compounds of the invention are used with a second therapeutic and/or prophylactic agent active against the same virus, the dose of each compound may either be the same as or different from that employed when each compound is used alone. Appropriate doses will be readily appreciated by those skilled in the art.
Pharmaceutical formulations include those suitable for oral, rectal, nasal, topical (including buccal and sub-lingual), vaginal or parenteral (including intramuscular, sub-cutaneous and intravenous) administration, or those in a form suitable for administration to the respiratory tract (including the nasal passages) for example by inhalation or insufflation. The formulations may, where appropriate, be conveniently presented in discrete dosage units, and may be prepared by any of the methods well known in the art of pharmacy. These methods include the step of bringing into association the active compound with liquid carriers or finely divided solid carriers or both, and then, if necessary, shaping the product into the desired formulation.
Pharmaceutical formulations suitable for oral administration may conveniently be presented as discrete units such as capsules, cachets or tablets each containing a predetermined amount of the active ingredient; as a powder or granules; as a solution, a suspension or as an emulsion. The active ingredient may also be presented as a bolus, electuary or paste. Tablets and capsules for oral administration may contain conventional excipients such as binding agents, fillers, lubricants, disintegrants, or wetting agents. The tablets may be coated according to methods well known in the art. Oral liquid preparations may for example be in the form of aqueous or oily suspensions, solutions, emulsions, syrups or elixirs, or may be presented as a dry product for constitution with water or other suitable vehicle before use. Such liquid preparations may contain conventional additives such as suspending agents, emulsifying agents, non-aqueous vehicles, which may include edible oils, or preservatives.
The compounds according to the invention may also be formulated for parenteral administration by injection, for example bolus injection, or continuous infusion, and may be presented in unit dose form in ampoules, pre-filled syringes, small volume infusion or in multi-dose containers with an added preservative. The compositions may take such forms as suspensions, solutions, or emulsions in oily or aqueous vehicles, and may contain formulating agents such as suspending, stabilising and/or dispersing agents. Alternatively, the active ingredient may be in powder form, obtained by aseptic isolation of sterile solid or by lyophilisation from solution, for constitution with a suitable vehicle, eg. sterile, pyrogen-free water, before use.
For topical administration to the epidermis the compounds according to the invention may be formulated as ointments, creams or lotions, or as a transdermal patch. Ointments and creams may, for example, be formulated with an aqueous or oily base with the addition of suitable thickening and/or gelling agents. Lotions may be formulated with an aqueous or oily base, and will in general also contain one or more emulsifying agents, stabilising agents, dispersing agents, suspending agents, thickening agents, or colouring agents.
Formulations suitable for topical administration in the mouth include lozenges comprising active ingredient in a flavoured base, usually sucrose and gum acacia or gum tragacanth; pastilles comprising the active ingredient in an inert base such as gelatin or sucrose and gum acacia; and mouthwashes comprising the active ingredient in a suitable liquid carrier.
Pharmaceutical formulations suitable for rectal administration wherein the carrier is a solid are most preferably presented as unit dose suppositories. Suitable carriers include cocoa butter and other materials commonly used in the art, and the suppositories may be conveniently formed by admixture of the active compound with the softened or melted carrier(s) followed by chilling and shaping moulds.
Formulations suitable for vaginal administration may be presented as pessaries, tampons, creams, gels, pastes, foams or sprays containing in addition to the active ingredient such carriers as are known in the art to be appropriate.
For administration to the respiratory tract, including intranasal administration, the neuraminidase inhibitors may be administered by any of the methods and formulations employed in the art for administration to the respiratory tract.
Thus in general the compounds may be administered in the form of a solution or a suspension or as a dry powder.
Solutions and suspensions will generally be aqueous, for example prepared from water alone (for example sterile or pyrogen-free water) or water and a physiologically acceptable co-solvent (for example ethanol, propylene glycol or polyethylene glycols such as PEG 400).
Such solutions or suspensions may additionally contain other excipients for example preservatives (such as benzalkonium chloride), solubilising agents/surfactants such as polysorbates (eg. Tween 80, Span 80, benzalkonium chloride), buffering agents, isotonicity-adjusting agents (for example sodium chloride), absorption enhancers and viscosity enhancers. Suspensions may additionally contain suspending agents (for example microcrystalline cellulose, carboxymethyl cellulose sodium).
Solutions or suspensions are applied directly to the nasal cavity by conventional means, for example with a dropper, pipette or spray. The formulations may be provided in single or multidose form. In the latter case a means of dose metering is desirably provided. In the case of a dropper or pipette this may be achieved by the patient administering an appropriate, predetermined volume of the solution or suspension. In the case of a spray this may be achieved for example by means of a metering atomising spray pump.
Administration to the respiratory tract may also be achieved by means of an aerosol formulation in which the compound is provided in a pressurised pack with a suitable propellant, such as a chlorofluorocarbon (CFC), for example dichlorodifluoromethane, trichlorofluoromethane or dichlorotetrafluoroethane, carbon dioxide or other suitable gas. The aerosol may conveniently also contain a surfactant such as lecithin. The dose of drug may be controlled by provision of a metered valve.
Alternatively the compounds may be provided in the form of a dry powder, for example a powder mix of the compound in a suitable powder base such as lactose, starch, starch derivatives such as hydroxypropylmethyl cellulose and polyvinylpyrrolidine (PVP). Conveniently the powder carrier will form a gel in the nasal cavity. The powder composition may be presented in unit dose form, for example in capsules or cartridges of eg. gelatin, or blister packs from which the powder may be administered by means of an inhaler.
In formulations intended for administration to the respiratory tract, including intranasal formulations, the compound will generally have a small particle size, for example of the order of 5 microns or less. Such a particle size may be obtained by means known in the art, for example by micronisation.
When desired, formulations adapted to give sustained release of the active ingredient may be employed.
Preferably the compounds of the invention are administered to the respiratory tract by inhalation, insufflation or intranasal administration, or a combination thereof.
“Relenza” is administered by oral inhalation as a free-flow powder via a “Diskhaler” (trade marks of the GlaxoSmithKline group of companies). A similar formulation would be suitable for the present invention.
Thus, according to an eighth aspect of the present invention there is provided an inhaler which contains a formulation as defined above.
It will be appreciated that the inhaler may also be in the form of a meter dose aerosol inhaler.
For the purposes of this specification it will be clearly understood that the word “comprising” means “including but not limited to”, and that the word “comprises” has a corresponding meaning.
All publications, including but not limited to patents and patent applications, cited in this specification are herein incorporated by reference as if each individual publication were specifically and individually indicated to be incorporated by reference herein as though fully set forth.
DETAILED DESCRIPTION OF THE INVENTION
The invention will now be described in detail by way of reference only to the following non-limiting examples.
Machine Methods
Method A (LC/MS)
Micromass Platform II mass spectrometer operating in positive ion electrospray mode, mass range 100–1000 amu.
Column: 3.3 cm×4.6 mm ID, 3 μm ABZ+PLUS
Flow Rate: 3 ml/min
Injection Volume: 5 μl
Solvent A: 95% acetonitrile+0.05% formic acid
Solvent B: 0.1% formic acid+10 mMolar ammonium acetate
Gradient: 0–100% A/5 min, 100–0% B/5 min
Method B
The prep column used was a Supelcosil ABZplus(10 cm×2.12 cm).
UV wavelength: 230 nm
Flow: 4 ml/min
Solvent A: acetonitrile+0.05% TFA
Solvent B: water+0.1% TFA
Gradient: 20–40% A/20 min, 40% A/20 min, 40–100% A/0.3 min, 100% A/15 min, 100–20% A/3 min
Abbreviations
TFA trifluoroacetic acid
DMAP 4-dimethylaminopyridine
SPE solid phase extraction
DPM diphenylmethane
BOC t-butoxycarbonyl group
Preparation of Intermediate 1
Benzhydryl (2R,3R,4S)-3-(acetylamino)-4-({(E)-[(tert-butoxycarbonyl)amino][(tert-butoxycarbonyl)imino]methyl}amino)-2-[(1R,2R)-1,2,3-trihydroxypropyl]-3,4-dihydro-2H-pyran-6-carboxylate (see J. Med. Chem. 1998, 41, 787–797) (12.38 g; 17.7 mmoles) was dissolved in dry acetonitrile (130 ml) under nitrogen at room temperature. The solution was stirred and 1,1′-carbonyldiimidazole (2.87 g; 17.7 mmoles) was added. After 16 hours LC/MS showed the presence of starting triol so further 1,1′-carbonyldiimidazole (total of 0.493 g; 3 mmoles) was added. After a few hours LC/MS showed no triol present. The solvent was evaporated and the residue flash columned on silica, eluting with 1:1 ethyl acetate/40–60 petroleum ether. Fractions containing wanted product were evaporated then taken up in dichloromethane, dried with sodium sulphate, filtered and evaporated to give Intermediate 1 (benzhydryl (2R,3R,4S)-3-(acetylamino)-4-({[(tert-butoxycarbonyl)amino][(tert-butoxycarbonyl)imino]methyl}amino)-2-{(S)-hydroxy[(4R)-2-oxo-1,3-dioxolan-4-yl]methyl}-3,4-dihydro-2H-pyran-6-carboxylate) as an off white solid (11.05 g; 86%).
Preparation of Intermediate 10
Intermediate 1 (0.4 g; 0.56 mmole) was dissolved in dry dichloromethane (0.5 ml). To this was added DMAP (20 mg) and 4 molecular sieves type 3A followed by intermediate 5 (50 mg; 0.19 mmole). The mixture was refluxed overnight then applied directly to a 10 g Si SPE cartridge eluted with diethyl ether and ethyl acetate to give intermediate 10 as a colourless glass (0.16 g, 50% yield).
LC/MS (method A) showed (M+2H + )/2=858; T RET =4.68 min.
Similarly prepared were the following:
n diisocyanate dicarbamate (M + 2H + )/2 T RET (min) 10 intermediate 2 intermediate 7 837 4.58 11 intermediate 3 intermediate 8 844 4.68 12 intermediate 4 intermediate 9 851 4.66 14 intermediate 6 intermediate 11 865 4.75
Preparation of Intermediate 15
Intermediate 10 (0.16 g; 0.093 mmole) was dissolved in a 10:1 mixture of dichloromethane: anisole (6.3 ml) at room temperature. To this was added TFA (6.3 ml) and the resulting solution was stirred for 2.5 hours then evaporated in vacuo. Trituration of the residue with ether gave intermediate 15 as the di-TFA salt (92 mg; 82% yield). LC/MS (method A) showed (M+2H + )/2=492; T RET =2.61 min.
Similarly prepared were the following:
starting
n
material
product
(M + 2H + )/2
T RET (min)
10
intermediate 7
intermediate 12
471
2.31
11
intermediate 8
intermediate 13
478
2.43
12
intermediate 9
intermediate 14
485
2.51
14
intermediate 11
intermediate 16
499
2.68
EXAMPLE 4
n=13
(2R,3R,4S)-3-(acetylamino)-2-{(1R,21R,22R)-21-((2R,3R,4S)-3-(acetylamino)-4-{[amino(imino)methyl]amino}-6-carboxy-3,4-dihydro-2H-pyran-2-yl)-1-[(1R)-1,2-dihydroxyethyl]-22,23-dihydroxy-3,19-dioxo-2,20-dioxa-4,18-diazatricos-1-yl}-4-{[amino(imino)methyl]amino}-3,4-dihydro-2H-pyran-6-carboxylic acid bis(trifluoroacetic acid salt)
Intermediate 15 (92 mg; 0.076 mmole) was dissolved in a mixture of water (16 ml) and methanol (16 ml). To this was added triethylamine (4 ml) and the solution was stirred for 1 hour. Volatile organics were removed in vacuo and the residue adjusted to pH 2 with TFA. Reverse phase preparative HPLC (method B) gave example 4 as the di-TFA salt (35.5 mg; 40% yield). LC/MS (method A) showed (M+2H + )/2=466; T RET =2.45 min.
Elemental analysis:—Found: C, 42.00; H, 5.79; N, 11.00%. Calc for tetrahydrate: C, 41.95; H, 6.18; N, 11.38%. NMR(D 2 O) δ: 5.85 (2H, d, 2×CH); 4.85 (2H, dd, 2×CH); 4.46 (2H, dd, 2×CH); 4.34 (2H, dd, 2×CH); 4.05, 2H, t, 2×CH); 3.94 (2H, m, 2×CH); 3.58 (2H, d d, CH 2 ); 3.42 (2H, dd, CH 2 ); 2.95 (4H, m, 2×CH 2 ); 1.88 (6H, s, 2×CH 3 ); 1.38 (4H, br.m, 2×CH 2 ); 1.22–1.10 (18H, br.m, 9×CH 2 ) p.p.m.
EXAMPLE 4a
Large Scale Preparation of Example 4
Intermediate 15 (2.8 g; 2.3 mmoles) was dissolved in water (50.4 ml). To this was added methanol (50.4 ml) followed by triethylamine (6.4 ml; 46 mmoles). The resulting solution was stirred at room temperature for 5 hours, the volume of the reaction mixture was reduced by ca 33% in vacuo at 35 degrees C. then the pH was adjusted to 2 with TFA (0.5 ml). The acidified solution was then injected onto a Prochom LC50 HPLC system comprising of a 20 cm×5 cm column packed with 7 micron Kromasil C8 packing material. The column was subjected to gradient elution:
Solvent A: water+1% TFA Solvent B: 75% acetonitrile/water+1% TFA Flow: 80 ml/min Gradient: 0% B to 100% B/40 min
The appropriate fractions were combined and the acetonitrile was removed in vacuo at 35 degrees C. The aqueous residue was absorbed onto a 10 cm×22 mm column of Amberchrom CG-161 (PSDVB resin) and the column was washed with water then eluted with acetonitrile:MeOH:water 2:2:1 (500 ml). The solvent was removed in vacuo to yield a gum. The addition of isopropanol (20 ml) gave a solid which was dried to give the product as the zwitterion (1.68 g).
EXAMPLE 4b
Crystallisation of Example 4
The zwitterion (100 mg; 0.1075 mmoles) was dissolved in water (35 ml). To this was added sodium bicarbonate (18.06 mg; 0.215 mmoles) and the resulting solution was freeze-dried to give a white solid. A sample (2 mg) of this solid was dissolved in water (0.8 ml) and evaporated to a syrupy oil. Dioxan (1 ml) was added and a white solid formed. The solid was allowed to settle and the supernatent was removed. Further dioxan (1 ml) was added and the supernatant was again removed. This process was repeated twice more and the solid obtained was dried in vacuo. Examination under polarised light showed crystallinity.
Examples E1, E2, E3 and E5 were prepared using an analogous procedure to that of Example E4.
EXAMPLE 1
n=10
(2R,3R,4S)-3-(acetylamino)-2-{(1R,18R,19R)-18-((2R,3R,4S)-3-(acetylamino)-4-{[amino(imino)methyl]amino}-6-carboxy-3,4-dihydro-2H-pyran-2-yl)-1-[(1R)-1,2-dihydroxyethyl]-19,20-dihydroxy-3,16-dioxo-2,17-dioxa-4,15-diazaicos-1-yl}-4-{[amino(imino)methyl]amino}-3,4-dihydro-2H-pyran-6-carboxylic acid bis(trifluoroacetic acid salt)
LC/MS (method A) showed (M+2H + )/2=445; T RET =2.13 min.
EXAMPLE 2
n=11
(2R,3R,4S)-3-(acetylamino)-2-{(1R,19R,20R)-19-((2R,3R,4S)-3-(acetylamino)-4-{[amino(imino)methyl]amino}-6-carboxy-3,4-dihydro-2H-pyran-2-yl)-1-[(1R)-1,2-dihydroxyethyl]-20,21-dihydroxy-3,17-dioxo-2,18-dioxa-4,16-diazahenicos-1-yl}-4-{[amino(imino)methyl]amino}-3,4-dihydro-2H-pyran-6-carboxylic acid bis(trifluoroacetic acid salt)
LC/MS (method A) showed (M+2H + )/2=452; T RET =2.25 min.
EXAMPLE 3
n=12
(2R,3R,4S)-3-(acetylamino)-2-{(1R,20R,21R)-20-((2R,3R,4S)-3-(acetylamino)-4-{[amino(imino)methyl]amino}-6-carboxy-3,4-dihydro-2H-pyran-2-yl)-1-[(1R)-1,2-dihydroxyethyl]-21,22-dihydroxy-3,18-dioxo-2,19-dioxa-4,17-diazadocos-1-yl}-4-{[amino(imino)methyl]amino}-3,4-dihydro-2H-pyran-6-carboxylic acid bis(trifluoroacetic acid salt)
LC/MS (method A) showed (M+2H + )/2=459; T RET =2.34 min.
EXAMPLE 5
n=14
(2R,3R,4S)-3-(acetylamino)-2-{(1R,22R,23R)-22-((2R,3R,4S)-3-(acetylamino)-4-{[amino(imino)methyl]amino}-6-carboxy-3,4-dihydro-2H-pyran-2-yl)-1-[(1R)-1,2-dihydroxyethyl]-23,24-dihydroxy-3,20-dioxo-2,21-dioxa-4,19-diazatetracos-1-yl)}-4-{[amino(imino)methyl]amino}-3,4-dihydro-2H-pyran-6-carboxylic acid bis(trifluoroacetic acid salt)
LC/MS (method A) showed (M+2H + )/2=473; T RET =2.50 min.
EXAMPLE 6
Evaluation of the Compounds of Formula (I)—Inhibition of Influenza Virus Replication
Cytopathic effect (CPE) assays were performed essentially as described by Watanabe et al. (J. Virological Methods, 1994 48 257). MDCK cells were infected with a defined inoculum of virus (determined by experimentation to be the minimum sufficient to cause adequate CPE in 72 hours and to be susceptible to control compounds at concentrations considered to be consistent with published norms) in the presence serial dilutions of Compounds of the invention. Cultures were incubated for up to 72 hours at 37° C. in a 5% CO 2 atmosphere. The extent of CPE and hence viral replication was determined via metabolism of the viral dye 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) according to published methods (see for example, Watanabe et al., 1994). The compound concentration that inhibited CPE by 50% (ID 50 ) was calculated using a computer program for curve fitting. Influenza A/Sydney/5/97 and B/Harbin/7/95 viruses were assayed and the results are shown in Table 1. Comparable data for a specifically disclosed compound in WO 00/55149 and for compound A is also shown in Table 1.
TABLE 1
ID 50 μg/ml
ID 50 M
ID 50 μg/ml
ID 50 M
Description
A/Sydney/5/97+
A/Sydney/5/97+
B/Harbin/7/95
B/Harbin/7/95
Compound A
0.023 +/− 0.024
69
0.013 +/− 0.011
39
E1
0.0002
0.179
0.0001
0.09
E2
0.0001
0.09
0.0001
0.09
E3
0.0001, 0.0001
0.087
0.0001, 0.0001
0.087
E4
0.0001
0.086
0.0001
0.086
E5
0.0001
0.085
0.0003
0.26
Compound
0.0007, 0.0005
0.58, 0.75
0.007 +/− 0.01
5.8
Number 8*
Compound
0.057
66
>0.1
>115
Number 10*
*As referenced in WO 00/55149
+Data provided in WO 00/55149 related to the virus H3N2 isolate A/Victoria/3/75 rather than A H3N2 isolate A/Sydney/5/97. When comparing such data the person skilled in the art will appreciate that differences in antiviral potency are not uncommon for a given compound when analysed against several different viruses in vitro. For example, Woods et al (Antimicrob Agents Chemother 1993 37: 1473–9) have reported that Compound A exhibits a wide range of EC50values (from 0.02 to 0.16 uM) in in vitro assays involving recent clinical isolates. Accordingly, compound 8 was found to be more potent in CPE assays involving the recent influenza A H3N2 isolate A/Sydney/5/97 than the earlier H3N2 isolate A/Victoria/3/75.
Data provided in Table 1 demonstrate that the compounds E1–E5, in addition to being substantially more potent than the highly active compound A, are even more potent against A/Sydney/5/97 and substantially more potent against the recent influenza B isolate B/Harbin/7/95 than compounds 8 and 10 of WO 00/55149.
EXAMPLE 7
Plaque Reduction Assay
Madin Darby Canine Kidney (MDCK) cells are seeded into six well tissue culture plates and grown to confluency via standard methods. Influenza viruses are diluted in a minimal volume of phosphate buffered saline supplemented with 0.2% bovine serum albumin to yield an estimated titre of 50–100 plaque forming units (pfu) per well. After adsorption to the MDCK cells for one hour at 37° C. in a 5% CO 2 atmosphere the viral inocula is aspirated and replaced with viral growth media (minimal Eagle's media supplemented with BSA, trypsin and insulin/transferrin/selenium at optimal concentrations) containing sufficient agar or agarose (generally 1–2%) to cause the media to gel at room temperature and at 37° C. in a 5% CO 2 atmosphere until plaques develop (generally 2–4 days). Plaques can be visualised with a suitable stain (e.g. 0.4% crystal violet in formal saline) before counting. Antiviral potency is expressed as the concentration of test article which reduces plaque numbers by 50% of the untreated control value (EC 50 ).
EC 50 ng/ml
PRA
Example
A/WSN*
A/Vic*
A/Syd*
A/New*
A/Pan*
A/Bay*
Compound A
56, >100
5.5 +/− 8.2
2.4
0.27, 0.23
2.7, 3
35
3
0.0023
0.000429
2
0.06, 0.2
<0.0001
4
<0.0001
<0.001, <0.01, 0.2
<0.0001
0.043
<0.00001
5
<0.0001
<0.001, 0.02, 0.3
0.032
<0.0001
0.032
<0.0001
Amantadine
220
11
157
Oseltamivir
0.11
0.23
0.3
*A/WSN/33 BVLV09 (H1N1)
A/Victoria/3/75 BVLV017 (H3N2)
A/Sydney/5/97 BVLV015 (H3N2)
A/New Caledonia/20/99 BVLV008 (H1N1)
A/Panama/2007/99 BVLV008 (H3N2)
A/Bayern/7/95 BVL006 (H1N1)
EC 50 ng/ml
PRA
B/
Example
B/Vic*
Harb*
B/HongK*
B/Yam*
Compound A
3, 20
0.19
21 +/− 6
0.2, 3.1
3
0.009, 0.01
<0.0001
<0.0001, <0.0001
2
0.04, 0.05
<0.0001
4
0.01, 0.1
0.06
<0.0001
5
0.05, 0.1
0.37
<0.0001
Amantadine
>10000
2061
Oseltamivir
32
0.7
*B/Victoria/1/67
B/Hong Kong/5/72 BVLV012
B/Harbin/7/95 BVLV008
B/Yamanashi/166/98 BVLV007
EXAMPLE 8
Assessment of Long Duration of Action
Rodents are anaesthetised and dosed with compound of interest by the intra-tracheal route at a dose volume of 0.8 ml/kg. The rodent is then held in the vertical position until full recovery is achieved. At different time points, for example, 2, 8, 24 and 48 hours post-dose, level of compound in the lung tissue are assessed by analytical methods. Any analytical method suitable for detection of this type of compound may be used. The time at which levels of compound fall below the sensitivity of the analytical techniques identified will determine the residency time of the compound in lung tissue.
The rat lung retention data for selected compounds is shown below. Please note that all experiments included a co-dosed internal standard, namely compound 3 of International Patent Publication No. WO 02/20514, to permit comparison. The data are expressed as a ratio with respect to this compound, the structure of which is shown below.
The data for compound A is included for comparison purposes. The compounds of the invention have significantly greater retention at 7 days than Compound A when expressed as a ratio of compound concentration to standard concentration.
Rat lung retention assay results
Ratio Mean
Mean
Mean
(lung) (cmpd)/PCT
time point
dose
(cmpd)
(cmpd)
PCT AU01/01128
(PCT AU01/01128
AU01/01128
hrs
Compound
mg/kg
ng/g
ng/g
compound 3 ng/g
compound 3) ng/g
compound 3
48
Example 3
0.1
591
1117
655
1413
0.79
48
Example 3
0.1
1845
1840
48
Example 3
0.1
914
1744
168
Example 3
0.1
111
376
242
550
0.68
168
Example 3
0.1
471
580
168
Example 3
0.1
546
829
48
Example 4
0.1
2414
1772
1098
1044
1.70
48
Example 4
0.1
1927
1352
48
Example 4
0.1
977
681
168
Example 4
0.1
929
756
636
509
1.48
168
Example 4
0.1
914
524
168
Example 4
0.1
426
367
48
Example 5
0.1
3044
4803
784
1478
3.25
48
Example 5
0.1
6268
2046
48
Example 5
0.1
5097
1605
168
Example 5
0.1
2750
1798
632
363
4.95
168
Example 5
0.1
1255
242
168
Example 5
0.1
1388
216
48
Compound A (zanamivir)
0.1
421
352
698
1368
0.26
48
Compound A (zanamivir)
0.1
369
1901
48
Compound A (zanamivir)
0.1
267
1507
168
Compound A (zanamivir)
0.1
91
61
815
750
0.08
168
Compound A (zanamivir)
0.1
47
925
168
Compound A (zanamivir)
0.1
45
512
EXAMPLE 9
Alternative Assessment of Long Duration of Action and Efficacy
The protocol for infecting mice has been described previously (1–4). Mildly anaesthetised mice are inoculated into the external nares with influenza virus. Treatment procedure and regimen. A single dose of compound is administered at a defined time point up to 10 days prior to infection, preferably 4–7 days prior to infection, or following infection, preferably immediately following infection and up to 48 hours post infection. In most experiments, a non-lethal strain of influenza is used, and efficacy is assessed by reductions in lung virus titre. For mice given compound prior to infection, lungs are removed post infection either on a single day, or on days following infection, preferably days 1–4 post infection. Homogenised lung samples are assayed for virus using established methods, and the titres of viral load estimated and compared to titres of virus in lungs of untreated mice.
In those experiments where a mouse-adapted lethal strain of influenza is used, efficacy is assessed by an increase in survival rate and/or numbers of survivors, as compared to untreated mice.
REFERENCES
1. Ryan, D. M., J. Ticehurst, M. H. Dempsey, and C. R. Penn, 1994. Inhibition of influenza virus replication in mice by GG167 (4-guanidino-2,4-dideoxy-2,3-dehydro-N-acetylneuraminic acid) is consistent with extracellular activity of viral neuraminidase (sialidase). Antimicrob. Agents and Chemother. 38 (10):2270–2275.
2. von Itzstein M., W. -Y. Wu, G. B. Kok, M. S. Pegg, J. C. Dyason, B. Jin, T. V. Phan, M. L. Smythe, H. F. White, S. W. Oliver, P. M. Colman, J. N. Varghese, D. M. Ryan, J. M. Woods, R. C. Bethell, V. J. Hogham, J. M. Cameron, and C. R. Penn. 1993. Rational design of potent sialidase-based inhibitors of influenza virus replication. Nature (London) 363:418–423.
3. Woods, J. M., R. C. Bethell, J. A. V. Coates, N. Healey, S. A. Hiscox, B. A. Pearson, D. M. Ryan, J. Ticehurst, J. Tilling, S. A. Walcott, and C. R. Penn. 1993. 4-Guanidino-2,4-dideoxy-2,3-dehydro-N-acetylneuraminic acid is a highly effective inhibitor both of the sialidase (neuraminidase) and of growth of a wide range of influenza A and B viruses in vitro. Antimicrob. Agents Chemother. 37:1473–1479.
4. Robert J Fenton, Peter J Morley, Ian J Owens, David Gower, Simon Parry, Lee Crossman and Tony Wong (1999). Chemoprophylaxis of influenza A virus infections, with single doses of zanamivir, demonstrates that zanamivir is cleared slowly from the respiratory tract. Antimicrob. Agents and Chemother. 43, 11, 2642–2647.
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The invention relates to compounds of general formula (I); in which R is an amino or guanidino group; R 2 is acetyl or trifluoroacetyl; and n is an integer from 10 to 18 or a pharmaceutically acceptable derivative thereof, methods for their preparation, pharmaceutical formulations containing them or their use in the prevention or treatment of a viral infection
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CROSS-REFERENCE TO RELATED APPLICATIONS
The present invention is a continuation-in-part of U.S. application Ser. No. 08/478,669, filed Jun. 7, 1995, now U.S. Pat. No. 5,640,416.
FIELD OF THE INVENTION
The present invention is generally directed to communications receivers of direct sequence spread spectrum signals, and in particular, to digitally sampling the spread spectrum signal at an IF frequency (approximately 200 MHZ and below) and simultaneously despreading and downconverting the signal to baseband.
BACKGROUND OF THE INVENTION
A block diagram of a typical direct sequence spread spectrum system 100 is shown in FIG. 1. A transmitter 102 consists of an MPSK modulator 104 which typically utilizes either Binary (BPSK) or Quaternary (QPSK) phase shift keying, followed by a spreader 106 which multiplies the modulated signal by a digital PN (pseudo noise) spreading code 108. The PN code 108 is typically generated by a PN Code Generator 110 at a rate (referred to as the chipping rate) at least an order of magnitude faster than a data symbol rate of the modulator 104, thus spreading the spectrum across a much greater bandwidth. For a multiple user system, each user has his own unique PN code and the bandwidth can be shared among different users using code division multiple access (CDMA) techniques.
A receiver 112 generates an exact replica 109 of the transmit PN sequence and multiplies it by the received signal to despread and hence recover the original modulated waveform. The receiver 112 must incorporate some means of synchronizing the timing of the locally generated PN sequence to that of the received signal. Both code acquisition circuitry 111 and tracking circuitry 113 must be included.
The receiver 112 structure typically uses one of three general structures as shown in FIGS. 2(a), (b) and (c). In FIG. 2(a), the receiver RF input 200 is first downconverted to a wideband intermediate IF frequency signal 214 in a wideband IF stage 208. The IF bandwidth must be greater than the spread bandwidth of the transmit signal. The IF signal 214 is then despread by a PN sequence 204 which has been upconverted from baseband to the IF frequency. The resulting despread signal 206 appears at baseband and is then filtered by a narrowband lowpass filter 202 with a bandwidth on the order of the data symbol rate.
A second scheme, shown in FIG. 2(b), also downconverts the RF signal 200 in the wideband IF stage 208. The despreading operation occurs at the IF frequency, although it is accomplished by multiplying the IF signal 214 by the baseband PN sequence 215. After despreading, the signal bandwidth is reduced, and the signal can then be filtered with a narrowband IF filter 210. The narrowband signal is then downconverted to baseband in the narrowband IF stage followed by narrowband baseband filtering.
The third scheme performs despreading at baseband as shown in FIG. 2(c). The wideband RF signal 200 is downconverted to a wideband baseband signal 216 and then filtered with a wideband baseband filter 212. The baseband signal is then despread by multiplying it by the baseband PN sequence 215 followed by narrowband baseband filtering.
One disadvantage of an all analog implementation of the IF and despreading circuits is the large number of components typically required. Each IF stage requires a local oscillator, mixer and filter. The despreading mixer must remain flat over a large bandwidth and accept a high slew-rate digital PN input. If pre-filtering is employed prior to despreading to improve noise performance, it typically exhibits a non-ideal frequency and time delay response, resulting in sub-optimum performance. The narrowband filter following the despreader should be reasonably sharp, often resulting in a physically large device. The baseband version of the despreader requires a complex downconverter where the local oscillator must be split into its in-phase and quadrature components. In addition, the phase noise of the local oscillators must be tightly controlled or there will be a performance loss in the subsequent coherent MPSK demodulator. DC offsets are also a concern and should be removed prior to demodulation. Analog circuits also suffer from component drift and aging and may be difficult to obtain with very tight tolerances.
Although the PN sequence is generated using digital techniques, the remaining circuitry has often been implemented using analog techniques. The digitally modulated MPSK signal is typically not converted to digital form until after the despreading operation. However, recently there has been great interest in implementing the despreader in digital form as well. A block diagram of a prior art digital despreader 300 which performs despreading at baseband is shown in FIG. 3. The scheme accepts a wideband IF signal 214 as depicted in FIG. 2(c) and digitally samples it directly in the wideband IF stage using A/D converter 301. After sampling by the A/D converter 301, the signal 308 is downconverted to baseband by digitally multiplying it by in-phase 310 and quadrature 312 numerically controlled oscillators. The complex baseband signal is filtered with a very broad accumulate and dump filter 304 which simply averages two adjacent samples. The filtered signal is then despread with a baseband PN sequence. The steerable clock generator 302, which is controlled by an external chip timing control signal 306, outputs a sample clock 314 to the A/D converter 301. The timing phase must be accurately controlled according to the PN timing acquisition 111 and tracking 113 mechanisms following the despreader.
The prior art digitally implemented downconverter/despreader has overcome many of the disadvantages of equivalent analog circuits. Only a single A/D converter is required and sampling is performed directly in the wideband IF where DC offsets can easily be removed. However, this scheme still requires a sampling rate approximately an order of magnitude higher than the chipping rate due to the poor amplitude response of the baseband digital filter 304 following the downconverter. A disadvantage inherent to all of the prior art methods is that they each use an analog clock circuit to track the timing phase of the PN sequence. Such a circuit must be highly stable and shielded from external noise sources. It also requires a finite amount of settling timing to slew the clock to a desired timing phase value and suffers from phase jitter about the nominal value. In addition, the circuitry needed to precisely adjust the phase of the high frequency chip timing clock is often complex. Recent digital implementations of the steerable clock generator 302 utilize direct digital synthesis where a numerically controlled oscillator drives a high frequency D/A converter. This is an expensive solution.
The digital scheme as shown in FIG. 3 has a second problem with timing control. Timing synchronization is accomplished by adjusting the phase of the A/D converter sample clock prior to the downconversion operation. The IF sub-sampling technique employed actually creates an alias of the IF signal separated from the IF frequency by an integral multiple of the sample rate, f s . However, as the sample rate is changed by the clock generator circuitry to track the PN timing, the carrier frequency and phase change by a multiple of f s . This can cause excessive phase jitter in the carrier phase and requires some means of compensation.
There are many examples found in the prior art which attempt to correct the above-noted shortcomings. Cowart, in related U.S. Pat. Nos. 5,029,180, 5,189,683 and 5,146,471, represents a low-cost implementation of a direct sequence spread spectrum (hereafter referred to as DS SS) transceiver suitable for integration into a single chip. Cowart assumes that the carrier frequency, chip rate, and data symbol rate are all synchronized from a common frequency source. Cowart also requires that the actual receive frequency and the receiver reference oscillator frequency be nearly identical by deriving them from stable crystal oscillators at frequencies below 50 MHZ. The primary application of Cowart is for transmission over power lines.
Cowart, however, uses hard-limiting in the receiver and only performs coarse timing tracking (within +/-1/4 of a chip period) of the received PN (pseudo noise) chipping sequence. In addition, Cowart cannot make precise chip timing adjustments and the bit error performance over noisy channels is sub-optimal.
Omura et al., in U.S. Pat. Nos. 5,166,952, 5,157,686 and 5,253,268, discuss a DS SS receiver and transmitter which employ either pulse position modulation or multiple chip code modulation. A matched filter correlator, matched to the transmit PN codes, is described followed by non-coherent demodulation.
Although the receiver of Omura performs digital sampling of the signal prior to despreading at a sample rate which is an integral multiple of the PN chip rate, two A/D converters are required. In addition, downconversion is performed by analog means and there is no fine tracking of the received PN chip timing. The resolution of chip timing adjustments is a function of the A/D sample rate and thus an excessively high sample rate is required for high resolution adjustment. In this solution, the bit error performance over noisy channels is also sub-optimal.
Soleimani, et al., U.S. Pat. No. 5,208,829, disclose a satellite communications system for providing maximum power output in a spread spectrum signal transmission. Filter designs for both the transmitter and receiver which provide a maximally flat frequency response over the band of interest are given. A receiver structure is described which can receive either spread or non-spread signals.
The spread-spectrum receiver design of Soleimani is based on conventional techniques. The receiver performs A/D conversion prior to despreading, but two converters are required rather than one. The receiver structure performs analog downconversion to baseband prior to despreading and the PN chip timing adjustments require an external VCXO circuit. This solution requires a high number of precision components making it expensive and complex.
SUMMARY OF THE INVENTION
A scheme has been devised to digitally sample an analog direct sequence spread spectrum signal at an IF frequency (approximately 200 MHZ and below), downconvert it to baseband and despread it. The scheme eliminates the need for an analog IF downconversion stage (mixer, oscillator, and filter) and also generates perfectly matched in-phase and quadrature samples required for subsequent multiple phase shift keying (MPSK) demodulation. In addition, received sample timing phase adjustments are accomplished digitally using a novel FIR filter structure, eliminating the need for analog clock steering circuitry. The technique has the unique feature of digitally tracking the timing phase of the PN sequence without the need for steering an external hardware clock. Matched filtering on the bandlimited spread waveform is also accomplished, greatly improving receiver performance. Two additional processing channels are included for timing synchronization of the receiver PN code sequence using an early/late gate synchronizer. The additional processing channels are also used during initial PN code acquisition to reduce the acquisition time by a factor of three.
The actual despreading, downconversion, and matched filtering operations have been defined in such a way that the digital processing required is greatly simplified, facilitating implementation into a single custom digital chip or several inexpensive field programmable gate arrays (FPGAs). Digital bandpass sampling techniques are employed where the signal is sampled at a rate on the order of the bandwidth of the spread spectrum signal directly at IF frequencies. However, since the sample rate is typically much higher than the data rate (because the spreading chip rate is much higher than the data rate), very few bits are required in the A/D converter. In addition, only a single A/D converter is required, compared to quadrature baseband analog downconverters which use two A/D converters. The processed, despread early, punctual, and late complex outputs are sampled at the data symbol rate and the I/Q channels have perfect phase and gain matching. They can then be further processed at this low rate using prior art techniques in a programmable digital signal processor (DSP) or similar device.
The present invention has all of the advantages inherent in a digital approach such as facilitating implementation into a single integrated circuit chip for low cost, size and power, but it also possesses several new advantages. Narrowband digital FIR filtering is employed after downconversion so that a reduced A/D sample rate of four samples per symbol is feasible. Such a filter also improves bit error performance in noisy RF links and reduces the analog anti-aliasing filter requirements. Another prime advantage is that the polyphase filter structure employed can be used to perform sample timing phase adjustments. Advantageously, the use of a digital filter reduces noise prior to despreading. Because timing phase is adjusted after downconversion, the timing phase adjustments do not severely affect the carrier phase as in the prior art method of FIG. 3. In addition, the timing phase can be set to any exact value within the resolution of the polyphase filter instantaneously without any ringing or settling time. Adjusting sample timing phase after downconversion eliminates carrier phase jitter inherent in digital systems which adjust the sample timing first.
If bandlimiting filtering of the spread spectrum signal is performed in the transmitter (i.e. square-root raised cosine) then an optimal digital matched filter can be implemented in the receiver. The filter coefficients can also be easily changed to null out known sources of interference or to adapt to changing channel conditions. Antialiasing filter requirements are relaxed due to digital filtering and the invention is readily adaptable to multiple bit rates and spread factors.
The present invention provides an apparatus for digitally downconverting and despreading an analog direct sequence spread spectrum signal, comprising: a free-running, non-steered, clock generator which outputs an A/D sample clock; the A/D sample clock having a rate which is an integral multiple of a chip rate of the spread spectrum signal; an A/D converter which receives the spread spectrum signal and the A/D sample clock and outputs a digitized signal from the spread spectrum signal; a local pseudo-noise sequence signal generator which outputs a local pseudo-noise sequence signal; a complex downconverter/polyphase filter which receives the digitized signal and the A/D sample clock and a sample timing phase control signal, simultaneously filters and donwconverts the digitized signal to baseband, corrects timing phase misalignment between the digitized signal and the locally generated pseudo-noise sequence signal, and outputs a complex corrected baseband signal; an impulse response of the downconverter/polyphase filter is matched to a pulse shape of the spread spectrum signal; a demultiplexer which receives the complex corrected baseband signal from the complex downconverter/polyphase filter and separates the complex corrected baseband signal into a complex punctual signal and a complex early/late signal and outputs the complex punctual and early/late signals; the complex punctual signal consists of samples of the complex corrected baseband signal detected at chip detection points; and the complex early/late signal consists of samples of the corrected signal detected at chip transition points; an early channel processor which receives the complex early/late signal, despreads and accumulates the complex early/late signal using the locally generated pseudo-noise sequence signal and outputs a complex early timing error signal; a punctual channel processor which receives the complex punctual signal, delays the locally generated pseudo-noise sequence signal, despreads and accumulates the punctual signal using the delayed locally generated pseudo-noise sequence signal, and outputs a complex data symbol; a late channel processor which receives the complex early/late signal, further delays the locally generated pseudo-noise sequence signal, relative to the delayed locally generated pseudo-noise sequence signal, despreads and accumulates the early/late signal using the further delayed locally generated pseudo-noise sequence signal and outputs a complex late timing error signal; and a digital signal processor which receives the complex early timing error signal, the complex data symbol and the complex late timing error signal and performs coherent carrier frequency and phase tracking and MPSK demodulation on a complex data symbol and which outputs a demodulated data bit, sample timing phase control signal and filter coefficient values.
The present invention is also directed to a method of digitally downconverting and despreading an analog direct sequence spread spectrum signal, comprising the steps of: generating a free-running, non-steered, A/D sample clock; the A/D sample clock having a rate which is an integral multiple of a chip rate of the spread spectrum signal; converting the spread spectrum signal into a digitized signal using the A/D sample clock and outputting a digitized signal; generating a local pseudo-noise sequence signal; simultaneously downconverting to baseband and filtering the digitized signal with a polyphase filter, correcting timing phase misalignment between the digitized signal and the locally generated pseudo-noise sequence signal and outputting a complex corrected baseband signal; separating the complex corrected baseband signal into a complex punctual signal and a complex early/late signal; outputting the complex punctual and early/late signals; the complex punctual signal consisting of samples of the complex corrected baseband signal detected at chip detection points; and the complex early/late signal consisting of samples of the complex corrected baseband signal detected at chip transition points; despreading and accumulating the complex early/late signal using the locally generated pseudo-noise sequence signal and outputting a complex early timing error signal; delaying the locally generated pseudo-noise sequence signal, despreading and accumulating the complex punctual signal using the delayed locally generated pseudo-noise sequence signal, and outputting a complex data symbol; further delaying the locally generated pseudo-noise sequence signal, relative to the delayed locally generated pseudo-noise sequence signal, despreading and accumulating the complex early/late signal using the further delayed locally generated pseudo-noise sequence signal and outputting a complex late timing error signal; and performing coherent carrier frequency and phase tracking and MPSK demodulation on a complex data symbol and outputting a demodulated data bit, sample timing phase control signal and filter coefficient values.
The polyphase filter used in filtering can also be impulse response matched to a pulse shape of the spread spectrum signal.
The inventor also has discovered that, by obviating the need for a steered clock, the above-described technique of the invention is very useful in multi-channel applications as well. By increasing the number of computations by a factor of M as compared with the first embodiment, while at the same time using much of the circuitry from the first embodiment, it is possible to provide a very efficient multi-channel digital downconverter/spreader.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other attendant advantages and features of the present invention will become readily apparent upon consideration of the following detailed description of the present invention when considered in conjunction with the drawings, wherein like reference numerals used throughout the figures thereof designate like parts, and wherein:
FIG. 1 is a block diagram of a typical direct sequence spread spectrum communications system;
FIGS. 2(a)-2(c) represent block diagrams of three general structures for a typical receiver;
FIG. 3 is a block diagram of a prior art digital despreader;
FIG. 4 is a block diagram of a spread spectrum receiver employing a technique of the present invention;
FIGS. 5(a)-5(b) are block diagrams representing the concept of the digital downconverter/despreader of the present invention;
FIGS. 6(a)-6(f) are graphs of the spread spectrum receiver spectrums;
FIGS. 7(a)-7(c) are diagrams illustrating the PN timing acquisition and tracking process in the receiver;
FIG. 8 is a graph of polyphase filter coefficients;
FIG. 9 is a graph of the frequency response of a 30% square root raised cosine filter;
FIG. 10 is a graph of the frequency response of filter bank 0;
FIG. 11 is a timing diagram representing the timing relationship between various signals found in a preferred embodiment of the present invention;
FIG. 12 is a block diagram of a digital despreader/downconverter constructed in accordance with a preferred embodiment of the present invention;
FIG. 13 is a block diagram showing further details of the digital despreader/downconverter constructed in accordance with a preferred embodiment of the present invention;
FIG. 14 is a block diagram of a prior art multi-channel digital despreader;
FIG. 15 is a block diagram of a multi-channel spread spectrum receiver employing a technique of the present invention;
FIG. 16 is a block diagram of a multi-channel digital despreader/downconverter constructed in accordance with a second preferred embodiment of the present invention; and
FIG. 17 is a block diagram showing further details of the multi-channel digital despreader/downconverter constructed in accordance with the second preferred embodiment.
DETAILED DESCRIPTION OF THE INVENTION
A block diagram of a spread spectrum receiver employing the invention is shown in FIG. 4. The receiver 112 utilizes the baseband despreading concept depicted in FIG. 2(c). As will be discussed in greater detail below, the receiver 400 operates with a free running clock generator 412, and simultaneously performs sample timing phase adjustments, down conversion, and matched filtering using digital downconverter/despreader/polyphase filter 408.
The RF signal 200 from the antenna is first processed in a typical RF stage 401 where it is downconverted to a wideband IF signal by a wideband downconverter 403. The wideband IF signal is adjusted to the proper level for A/D conversion using an AGC amplifier 400 either in the RF or IF stage. The AGC amplifier 400 is controlled by a signal level detector (not shown) either in the analog front-end or in the digital demodulator.
An IF local oscillator 402 may be tunable by an external frequency control signal 420 if the input signal is expected to have large frequency uncertainties. The signal loss due to a frequency uncertainity of Δf in the matched filter following the despreader is expressed as follows: ##EQU1## The loss is tabulated in Table 1 below. An offset of 10% of the symbol rate corresponds to a loss of just over 0.1 dB. It is therefore recommended to employ frequency control for any offset in excess of 0.1R s . The frequency control signal is assumed to be derived either within the RF stage itself or from the MPSK demodulator.
TABLE 1______________________________________Computed Signal Loss after Integrate and Dump Filtering VersusRelative Frequency Offset (as a Percentage of Symbol Rate) of CarrierFrequency Offset, .increment.fT.sub.s Signal Loss______________________________________ 0% 0 dB 1% .0014 dB 5% .036 dB10% .14 dB15% .32 dB20% .58 dB25% .91 dB33% 1.62 dB50% 3.92 dB______________________________________
The IF signal is filtered with a wideband IF bandpass filter 404 which has a shape factor of approximately 2:1 and also functions as an antialiasing filter. The IF signal 416 is then sampled by an A/D converter 406 at a rate of four samples per chip and processed in a custom digital IC 408 using the techniques of the invention. The A/D sample clock 410 is derived from a free-running clock generator 412 which is not steered and is therefore not locked to the PN chip timing of the received signal 200. The IF signal 416 is downconverted to baseband and then lowpass filtered in the digital IC 408 by a polyphase filter having a response which is matched to that of the transmit chip pulse shape. The polyphase filter also serves to correct any timing phase misalignment between the received signal and the locally generated PN sequence. The filtered signal is then despread by early, punctual, and late despreaders, matched filtered, and decimated to the symbol rate.
The output of the downconverter/despreader IC 408 is a set of complex digital data symbols, decimated to the symbol rate. The resulting in-phase and quadrature (I and Q) symbols for all three channels are sent to a standard digital signal processor (DSP) IC 414. The DSP IC 414 performs coherent carrier frequency and phase tracking and MPSK demodulation on the punctual channel. The (I and Q) early and late symbols are processed by DSP IC 414 to obtain a sample timing phase control signal 418.
The DSP IC 414 also serves as a controller for the downconverter/despreader IC 408. Although a DSP IC 414 is assumed here, there is no technical reason why the functions of the DSP IC 414 could not also be incorporated into either the same custom digital IC as the downconverter/despreader 408 or implemented in another custom digital IC. However, the DSP IC 414 provides considerable flexibility in implementing various digital acquisition and tracking algorithms.
The digital downconverter/despreader concept is illustrated in FIGS. 5(a) and 5(b). The technique is best illustrated by an example. Assume the spread spectrum signal 416 has a chip rate, R c , of 8 MHZ and is filtered in the transmitter with a 30% rolloff square-root raised cosine filter. Thus, the transmit signal two-sided bandwidth is 10.4 MHZ. RF stage 401 will be designed for an IF frequency, F c , of 40 MHZ. Note that the IF frequency must be greater than 5.2 MHZ to prevent spectral overlap. Refer to FIG. 6(a) for a spectral plot of the IF signal. At the output of the analog IF mixer 403 there will be spectral components at both -40 MHZ and +40 MHZ.
It will be shown that it is highly advantageous to sample at a rate f s of exactly four times the chip rate, so f s is chosen to be 32 MHZ. A sample clock 410 is generated by a free-running clock generator 412. Sampling spread spectrum signal 416 with A/D converter 406 produces an aliased spectrum as shown in FIG. 6(b). Note that the negative spectral component (designated as A in the figure) and the positive spectral component (designated as B), each repeat every 32 MHZ. Also note that the aliased spectrum is symmetric and the two aliases closer to baseband are at ±f s /4=R c =8 MHZ.
The spectral characteristics of the analog antialiasing filter 404 required prior to sampling are shown in FIGS. 6(a) and (b). The signal spectrum shown will also contain a broadband noise component. However, as shown in the figure, if the two-sided stop bandwidth of the filter 404 is at most 2.7R c (for a signal bandwidth of 1.3R c ) the noise components will not alias into the signal bandwidth. Consequently, a filter shape factor 2:1 is required, which equates to approximately five filter poles. Such a filter can be implemented quite economically.
The 8 MHZ spectral component is donwconverted to baseband as shown in FIG. 5(a) by multiplying the A/D sample 502 by a negative 8 MHZ complex sinusoid 506, 508. Since the carrier frequency is exactly one fourth of the sample rate of the A/D sample clock 410, this degenerates to multiplication by sequences of (1, 0, -1, 0, 1, 0, -1, 0, . . . ). The resulting spectrum is shown in FIG. 6(c). The complex baseband signal is filtered with a polyphase lowpass filter 501 to limit the wideband noise and remove the spectral aliases at -16 MHZ and +16 MHZ, as shown in FIG. 6(d). For optimal signal-to-noise ratio performance, the polyphase filter 501 has an impulse response which is matched to that of the transmitter, 30% square-root raised cosine, in the example case. The polyphase filter 501 also introduces a phase shift in the digital samples 502 to adjust the sample timing phase according to sample timing control signal 418, as will be described below. The filtering process includes a decimator 522 which performs sample rate decimation by a factor of 2:1. Note that any DC offset in the signal prior to A/D downconversion would be shifted into the stopband of the polyphase filter by the digital downconverter 510, 512 and effectively removed.
The real (I) signal 525 is separated into punctual I and early/late I signals 518, 519, respectively, and the imaginary (Q) signal 526 is separated into punctual Q and early/late Q signals 520, 521, respectively, with demultiplexers 523 and control logic 524. The punctual I and Q signals 518, 520, respectively, are then despread by a delayed PN sequence 530 by despreaders 505-3, 505-4, respectively, in punctual channel processor 509, as shown in FIG. 5(b). Assuming proper timing phase alignment between the delayed PN sequence 530 and punctual I and Q signals 518, 520, the despread narrowband spectrum of FIG. 6(e) results. The despread I and Q signals are then processed by accumulate and dump filters 503. Samples of the despread I and Q signals are accumulated for exactly one data symbol period and then the resulting complex data symbol 542, 543 is output to the DSP IC 414. Note that there are actually a total of six despreaders 505-1 . . . 505-6 and accumulate and dump filters 503 for the I and Q components of the early 507, punctual 509 and late 511 channel processors as shown in FIG. 5(b).
The real (cosine) and imaginary (sine) channels are then both despread by the PN sequence through a despreader 505, producing the narrowband MPSK-modulated spectrum of FIG. 6(e), assuming proper PN timing phase synchronization. The despread signal is then processed by an accumulate and dump filter (503. All the samples are accumulated for exactly one data symbol period in both the I and Q channels and then the resulting complex symbol is output to the DSP chip. Note that there are actually a total of six despreaders 505-1 . . . 505-6 and accumulate and dump filters 503 for the I and Q components of the early 507, punctual 509 and late 511 channel processors as shown in FIG. 5(b).
Digital despreading with a minimal amount of performance loss is greatly enhanced through the use of IF bandpass sampling. The IF frequency must be high enough to avoid any overlap between the sum and difference frequency mixing products in the IF mixer. In other words, the IF frequency must be greater than one half the two-sided signal bandwidth. The digital sample rate must be greater than the signal bandwidth but not necessarily greater than the IF frequency. Thus, sample rate is mainly a function of the signal chipping rate and it is permissible to choose an IF frequency much higher than the sample rate within the constraints of the components selected.
It can be shown that given an IF center frequency F c , sample rate f s , and two-sided signal bandwidth B, the following criteria must be met for ideal bandpass sampling:
ƒ.sub.s >2B (2) ##EQU2##
Therefore, the sample rate must be at least twice the bandwidth of the input signal and must be one of several discrete frequencies determined by the parameter n in equation (3). If f s is chosen to meet the two criteria, the aliases of the input spectrum will each be equally spaced from one another without overlap and thus the signal will be perfectly represented by the digital samples. It can also be shown that if the two criteria are met, there will be aliased spectral components at -f s /4 and +f s /4. If is convenient to choose a sample rate of 4R c , where R c is the chipping rate and the IF signal will alias to ÅR c as a result of the sampling process. Choosing such a relationship greatly simplifies the digital processing and permits the use of an antialiasing filter with a 2:1 shape factor (stopband to passband bandwidth ratio).
The A/D converter 406 resolution is not very critical due to the relatively high sample rate compared to the digital symbol rate. The quantization noise spectrum is relatively flat from -f s /2 to +f s /2. After despreading by despreaders 505-1 . . . 505-6, the signal bandwidth is greatly reduced and the majority of the broadband quantization noise will be removed by the accumulate and dump filter 503. For example, given a chipping rate of 255R s (R s is the data symbol rate), the sample rate will be 4*255R c =1020R s . The bandwidth reduction after despreading and matched filtering will reduce the quantization noise power by 10 log 10 (1020)=30 dB, which corresponds to an increase in resolution of five bits. Five bits of resolution is adequate for BPSK and QPSK demodulation.
In fact, a 1-bit A/D converter (hard limiter) is sufficient for many applications. However, significant distortion products will result from such a converter if there are any narrowband interfering signals within the spread spectrum signal bandwidth. Also, in cellular radio applications, signals can have a significant dynamic range because of the possible span of signal strength. For example, a receiver positioned in close proximity to a transmitting station will receive a very strong signal, while a receiver positioned distantly from the station will receive a very weak signal. Having a larger number of bits of resolution in the A/D converter can accommodate the dynamic range more adequately.
For the foregoing reasons, an A/D converter 406 having a resolution of four bits (or possibly greater, depending on the application) is preferred in the present invention, giving a signal-to-quantization noise ratio equivalent to a 9-bit converter after the accumulate and dump filter 503.
When sampling at IF frequencies, the timing uncertainty (aperture jitter) of the A/D converter 406 must be small enough that the amplitude error is less than one half an LSB. This error is given by ##EQU3## f max =the maximum signal frequency For m=4 bits and f max =200 MHZ, Δt=100 ps. A second constraint is present in that, since an A/D converter's input circuit is lowpass in nature, it must not exhibit much attenuation at f max .
The receiver 112 initially acquires the PN timing phase of the received signal by a repetitive search, correlating the complex baseband received signal 514, 515 with different epochs of the locally generated PN sequence until a peak in narrowband energy is detected. Typically, the time epoch is one-half of a chip period, T c /2. Thus, the locally generated PN sequence can be shifted in increments of two samples at a time until PN synchronization is obtained. As shown in FIG. 7(a), the locally generated PN sequence in the receiver initially is not time synchronized with the PN timing phase of the received signal. After the initial PN timing acquisition process is complete, the locally generated PN sequence will be time synchronized with an error less than T c /2, as shown in FIG. 7(b). There are several well-known acquisition detection techniques which can be implemented and which will not be discussed here.
Once acquisition has been obtained, the timing phase of A/D samples 502, relative to the PN timing phase, is tracked by making adjustments much smaller than T c /2, as shown in FIG. 7(c). The timing is steered by the sample timing phase control signal 418 from the early/late synchronization loop. All three channel processors (early 507, punctual 509 and late 511) can be utilized during timing acquisition. The PN sequences going to the despreaders 505 have relative timing offsets of 0, T c /2, and T c in channel processors 507, 509 and 511, respectively. Therefore, three time epochs can be correlated simultaneously, reducing the acquisition time by a factor of three.
Fine sample timing phase adjustments (to a resolution much finer than a half of a chip period) are made by interpolating the received samples to a higher rate, time-shifting the interpolated samples to the desired timing phase, and then decimating back down to the input sample rate. This process can be implemented quite efficiently using a polyphase filter structure. The filter is simply an FIR lowpass filter designed at a higher, interpolated sample rate. The filter coefficients can then be divided into different banks, each decimated to the input sample rate but with a different time delay. For example, given a 16-tap FIR filter sampled at a rate of 8 Hz, it can be divided into eight two-tap filters, each sampled at a 1 Hz sample rate as shown in FIG. 8. Filter bank 0 would consist of the first and ninth coefficients, filter bank 4 would consist of the fifth and thirteenth coefficients and so on. Timing phase adjustments are then performed by convolving the input samples by the filter bank with the desired delay.
To determine the necessary interpolated sample rate of the filter, a computer simulation was performed to measure the signal loss after the accumulate and dump filter 503 as a function of timing phase error in the despreading PN sequence. A baseband BPSK signal was spread by a PN sequence of length 64 and then despread by the identical sequence shifted in time by various fractions of a chip. The sample rate was 64 samples per chip for a total of 4096 samples per data symbol. The energy of the received symbols after a 4096 sample accumulate and dump operation was then measured. The energy loss as a function of timing offset error is tabulated in Table 2 below.
As shown in Table 2, an offset of 5/64 T c causes a despreading loss of less than 0.1 dB. A timing phase resolution of T c /32 is preferred because the loss is negligible (0.014 dB). Given that the A/D converter sample rate is four samples per chip, the polyphase filter must be designed for an interpolation ratio of 8:1. As seen in FIGS. 6(c) and (d), the filter must be sharp enough to remove the alias centered at 2R c , but should not disturb the baseband signal spectrum. Such a filter serves to remove white Gaussian noise present on the transmission channel. If it is not removed, the despreading process will spread it across the desired signal bandwidth, decreasing bit error performance. As is known, a filter with two-sided noise bandwidth equal to R c reduces the noise observed after despreading by an additional 0.5 dB compared to using a filter with a bandwidth of 2R c . The filter also can be useful in removing sources of narrowband interference prior to despreading which would also be spread across the desired signal bandwidth by the despreading operation.
TABLE 2______________________________________Simulated Signal Energy Loss after Integrate and Dump FilteringVersus Receiver Despreader PN Chip Timing ErrorSpread factor = 64, 64 samples/chip, Integrate and dumpperiod = 4096 samplesRx PN Timing Offset, T.sub.c /64 Signal Loss______________________________________0 0 dB1 .004 dB2 .014 dB3 .030 dB4 .046 dB5 .081 dB6 .12 dB7 .16 dB8 .21 dB9 .26 dB10 .32 dB16 .80 dB______________________________________
Ideally, the filter impulse response should be matched to the pulse shape of the transmitted chips (where a chip is defined as one epoch of the PN sequence). The raised cosine pulse shape provides the necessary bandlimiting characteristic in addition to having the property that is exhibits zero intersymbol interference (inter-chip interference in this case). For matched filtering, both the transmit filter and the receiver polyphase filter 501 will have identical square-root raised cosine frequency responses.
A 30% square-root raised cosine response can be approximated quite well with an aperture of 5 chip periods. The filter is designed at a sample rate of 32 samples per chip, for a total of 160 taps. The filter is divided into eight banks of 20 taps each. Thus, each output is obtained by convolving the input samples with a 20-tap filter. Nine-bit quantization of the coefficients is sufficient for near-ideal performance. Refer to FIG. 9 for a plot of the frequency response. The absolute delays of each bank are listed in Table 3. Note that each successive bank has a delay of T c /32 less than the previous one. Each bank has essentially the same frequency response and the response of bank 0 is plotted in FIG. 10. To retard the timing phase by T c /32, the filter coefficients should be changed to bank n-1 from bank n. To advance the phase by T c /32, the bank should be changed to n+1 from bank n. Discussion of these functions, for example, the boundary conditions of crossing over bank 0 or 7 will be discussed below.
TABLE 3______________________________________Delay of Polyphase Filter Banks, Filter Sample Rate = 32samples/chip Filter Bank Number Delay______________________________________0 (c0, c8, c16, . . . , c152) 79.5 · T.sub.c /321 (c1, c9, c17, . . . , c153) 78.5 · T.sub.c /322 (c2, c10, c18, . . . , c154) 77.5 · T.sub.c /323 (c3, c11, c19, . . . , c155) 76.5 · T.sub.c /324 (c4, c12, c20, . . . , c156) 75.5 · T.sub.c /325 (c5, c13, c21, . . . , c157) 74.5 · T.sub.c /326 (c6, c14, c22, . . . , c158) 73.5 · T.sub.c /327 (c7, c15, c23, . . . , c159) 72.5 · T.sub.c /32______________________________________
A process to simplify the polyphase filtering, downconversion, and despreading operations will now be shown. Assume we are given the following:
Chipping rate=R c =1/T c
Sample rate=f s =4 samples/chip
Sample period=T c /4
Carrier frequency after sampling=f s /4=R c
Spread factor (number of chips per data symbol)=N
Although not a necessary condition, for the current system it is also assumed that the PN sequence is synchronized with each data symbol, and thus, the N-length PN sequence repeats every symbol. The A/D samples 502 are denoted as x(n), where n is the sample index, and the sample time=nT c /4. As shown in FIG. 5, the A/D samples 502 are first downconverted to a complex baseband signal 514, 515, denoted as y(n), by multiplying the samples by the complex exponential 506, 508 through multipliers 510, 512, respectively.
y(n)=x(n)e.sup.j2πnf,/4/f.sbsp.S =x(n)e.sup.j2πnR.sbsp.C.sup./4R.sbsp.C =x(n)e.sup.jnπ/2(5)
Solving equation (5) in terms of its real and imaginary components, y r and y i , respectively, gives the following sequence:
real: y.sup.r (n)=x(n)·(-1).sup.n/2 for n even
=0 for n odd (6a)
imag: y.sup.i (n)=x(n)·(-1).sup.(n-1)/2 for n odd
=0 for n even (6b)
Next, the complex baseband sequence y(n) is convolved with a bank of polyphase filter coefficients. Each bank contains 20 real coefficients, c 0 , c 1 , . . . c 19 . It is noted that here the coefficients for a particular bank have been redesignated c 0 through c 19 for notational simplicity. It is understood that they are a subset of the original c 0 through c 159 coefficients. The convolution of y with the filter coefficients is given by: ##EQU4##
Equations (7a) and (7b) each assume that the filter outputs, z(n) 516, 517 are computed at a rate of four samples per chip. However it is only necessary to compute a filter output at a rate of two samples per chip. As shown in FIG. 5(a), signals 516, 517 are thus decimated to one-half the rate of the sample clock 410 by decimator 522. Signals 516, 517 consist of one sample aligned with the center of each raised cosine pulse (the chip detection point) per chip and one sample per chip at the chip transition point.
In addition, a demultiplexer 523 coupled with control logic 524 is used to separate the chip transition point samples 519, 521 from the chip detection point samples 518, 520. Signals 518, 520 drive the punctual channel processor 509, as shown in FIG. 5(b). Signals 519, 521 drive both the early channel processor 507 and the late channel processor 511. Signals 519, 521 are delayed in time by T c /2 from the punctual samples 518, 520. The sample rate of signals 518-521 is one sample per chip.
A delay locked loop is used to track the PN sequence timing phase. Consequently, a total of three channel processors 507, 509, 511 are required. The delay locked loop requires an early channel processor 507 where the received samples are despread by a PN sequence advanced by T c /2 in time, and a late channel processor 511 where the received samples are despread by a PN sequence delayed by T c /2 in time, relative to the timing phase of the PN sequence applied to the punctual channel.
It is apparent that each convolution operation only involves ten filter coefficients since every other sample of complex baseband signal 514, 515 is zero. It is also easy to show that the convolution operation for the complex early/late output samples 519, 521 utilizes the same filter coefficients as for the complex punctual outputs 518, 520 except the sign of the complex early/late outputs must be reversed. However, it is simpler to just ignore the sign change and account for it later in the calculation of the delay locked loop error signal in the DSP IC 414.
The complex punctual filter outputs 518, 520 will be denoted as z p (m), and the complex early/late filter outputs 519, 521 will be denoted as z e1 (m), where it is understood that m=0 corresponds to the optimal detection time for the punctual channel processor 509. The filter outputs are computed once per chip interval according to the following equations: ##EQU5##
For efficiency, the terms of the form c 2n ·(-1) n may be pre-computed so that the downconversion and polyphase filtering operations are combined into one convolution operation. Thus, the coefficients are stored in hardware with the sign of every other coefficient inverted.
After the above convolution operations are performed, the punctual samples are despread by the punctual despreaders 505-3, 505-4 and the early/late samples are despread by both the early 505-1, 505-2 and the late 505-5, 505-6 despreaders. The PN sequence, PN(), applied to each channel processor 507, 509, 511 will have the appropriate delay. Then a data symbol d(k) can be recovered after despreading and processing by an accumulate and dump filter 503. In the despreading operations of Equations 9(a)-9(f) below, d p (k), d e (k), and d 1 (k), refer to the complex data symbol 542, 543, complex early timing error signal 540, 541 and complex late timing error signal 544, 545 outputs associated with the k th data symbol where each output is computed once per data symbol interval. The argument of z p refers to the chip time index, where it is understood that the argument of z e1 refers to an absolute time of T c /2 earlier than the same argument of z p . ##EQU6##
It is assumed that sample timing adjustments can be made only at symbol boundaries. Normally, timing adjustments are made simply by changing to a new bank of filter coefficients as determined by the sample timing control signal 418. However, if a timing adjustment crosses an A/D sample (T c /4) boundary, an additional step is necessary. For example, if the current sample timing is achieved by using the last polyphase filter bank (bank 7) and it is desired to advance the timing by T c /32, the filter input delay line must be advanced by one sample. Filter bank zero must then be selected to achieve the proper timing. Similarly, if it is desired to retard the timing phase by T c /32 and polyphase filter bank zero is currently selected, it is necessary to delay the filter input delay line by one sample (i.e., reuse the current sample instead of shifting in a new one) and select polyphase filter bank seven. The two cases are outlined below and show the effects of the polyphase filtering operation.
Case 1--Advancing the Timing Phase Across a Sample Boundary
To advance the timing T c /32 when polyphase filter bank seven is selected, three new A/D samples must be shifted into the filter delay line instead of the usual four before generating the next filter output. Thus, the filter hardware is advanced by one A/D sample period (8T c /32). In addition, filter bank zero is selected, retarding the timing by 7T c /32 for a net timing advance of T c /32. However, there is an additional change that must be considered. The digital downconversion process is not affected by the sample timing shift since it occurs before timing adjustments are made. But the filtering process is affected. For example, assume that a complex punctual filter output 518, 520 at time index m=α was just computed, therefore, according to equations 8(a) and 8(b):
z.sub.p.sup.r (α)=c.sub.0 x(α)-c.sub.2 x(α-2)+c.sub.4 x(α-4)-c.sub.6 x(α-6)+c.sub.8 x(α-8)-c.sub.10 x(α-10)+c.sub.12 x(α-12)-c.sub.14 x(α-14)+c.sub.16 x(α-16)-c.sub.18 x(α-18) (10a)
z.sub.p.sup.i (α)=-c.sub.1 x(α-1)+c.sub.3 x(α-3)-c.sub.5 x(α-5)+c.sub.7 x(α-7)-c.sub.9 x(α-9)+c.sub.11 x(α-11)-c.sub.13 x(α-13)+c.sub.15 x(α-15)-c.sub.17 x(α-17)+c.sub.19 x(α-19) (10b)
Normally, the next punctual filter output is not computed until time t=(α+4)·Tc/4. To make a timing adjustment, compute the next output as soon as x(α+3) has been shifted into the filter delay line. After accounting for the downconversion process, the following is computed:
z.sub.p.sup.r (α+3)=-c.sub.1 x(α+2)+c.sub.3 x(α)-c.sub.5 x(α-2)+c.sub.7 x(α-4)-c.sub.9 x(α-6)+c.sub.11 x(α-8)-c.sub.13 x(α-10)+c.sub.15 x(α-12)-c.sub.17 x(α-14)+c.sub.19 x(α-16) (11a)
z.sub.p.sup.i (α+3)=-c.sub.0 x(α+3)+c.sub.2 x(α+1)-c.sub.4 x(α-1)+c.sub.6 x(α-3)-c.sub.8 x(α-5)+c.sub.10 x(α-7)-c.sub.12 x(α-9)+c.sub.14 x(α-11)-c.sub.16 x(α-13)+c.sub.18 x(α-15)(11b)
Note that the convolution operation is the same as in equation (10) above except that the coefficients used for the punctual real and imaginary outputs 518, 520 have been swapped and the signs of the coefficients now used for the imaginary output 520 have been reversed. The filter coefficients could be modified to reflect the new changes but it is simpler to leave them unaltered and account for them in the DSP control processor 414 after despreading. The DSP can then just swap real and imaginary symbols 542, 543 and perform the required sign inversions at the symbol rate.
The filter hardware will have to run slightly faster to handle this case. The first filter output at the advanced timing phase has to be computed one A/D sample period earlier than usual. An A/D sample clock that is slightly faster than four samples per chip could be used so that the hardware always acts to retard the timing phase. Another approach is to just not compute a filter output until the hardware is ready. The energy reduction for zeroing the output for one chip interval is negligible, especially for large spread factors. For example, for a spread factor of 64, deleting one output sample (chip) would reduce the signal energy of one symbol by 63/64 or 0.14 dB. Assuming that timing adjustments do not occur every symbol, the loss is negligible, especially in systems employing forward error correction coding.
Case 2--Retarding the Timing Phase Across a Sample Boundary
To retard the timing by T c /32 when polyphase filter bank zero is selected, five new samples are shifted into the filter delay line instead of the usual four before generating the next filter output. Thus, the filter hardware is delayed by one sample. In addition, filter bank seven is selected. Similar to advancing the timing phase across a sample boundary, case 1, the filter outputs must be modified. Again, assume that a complex punctual filter output was just computed at sample time index m=α and it is desired to retard the timing phase. To make a timing adjustment, shift x(α+1), x(α+2), x(α+3), x(α+4) and x(α+5) into the filter delay line and, after accounting for the downconversion process, according to equations 12(a) and 12(b):
z.sub.p.sup.r (α+5)=c.sub.1 x(α+4)-c.sub.3 x(α+2)+c.sub.5 x(α)-c.sub.7 x(α-2)+c.sub.9 x(α-4)-c.sub.11 x(α-6)+c.sub.13 x(α-8)-c.sub.15 x(α-10)+c.sub.17 x(α-12)-c.sub.19 x(α-14) (12a)
z.sub.p.sup.i (α+5)=c.sub.0 x(α+5)-c.sub.2 x(α+3)+c.sub.4 x(α+1)-c.sub.6 x(α-1)+c.sub.8 x(α-3)-c.sub.10 x(α-5)+c.sub.12 x(α-7)-c.sub.14 x(α-9)+c.sub.16 x(α-11)-c.sub.18 x(α-13) (12b)
Note that the real and imaginary filter coefficients have been swapped (as compared to equation (10)) as in case 1 above, but the signs of the coefficients now used for the real output 518 have been reversed. As in case 1, the DSP IC 414 can just swap real and imaginary symbols 542, 543 and perform the required sign inversions Thus the filtering and despreading operations do not have to be modified.
It has been described how the downconversion and pre-despreading filtering operations reduce to convolving the read A/D input sequence by a selected bank of ten complex coefficients and then decimating the sample rate by a factor of two to two samples per chip. A specific embodiment of the present invention used to perform the computations symbolized in FIGS. 5(a) and 5(b) as part of the overall spread spectrum receiver of FIG. 4 will now be discussed. FIG. 11 is a timing diagram to be referenced in conjunction with FIGS. 12 and 13 which are simplified hardware block diagrams.
As seen in FIG. 12, a 4-bit A/D input bus 502 is connected to a 4-bit×19 delay line (shift register file) 603. On the rising edge of each sample clock (4× Chip Clock) 410, as seen in FIG. 11, each bit of an A/D sample is clocked into one of four parallel shift registers. The filter coefficients are stored in ten arrays of 16×9-bit static RAM 609 which can be downloaded by DSP IC 414 or other control logic over an external 9-bit bus 605. Each RAM array 609 stores coefficients for one of the 10 filter taps and supplies a 9-bit operand to its associated multiplier 610. Each RAM array stores eight real coefficients followed by eight imaginary coefficients, corresponding to the eight different filter banks. A 3-bit bus 418 controls which of the eight filter banks to use, and is steered by timing adjustment control logic. Additional logic must also be provided to advance or retard the input delay line when changing the sample timing phase across a sample boundary. The signal "2× Chip Clock" 703 selects between the real and imaginary coefficients at every A/D sample period. Ten 4×9-bit multipliers 610 are used to perform all ten filter tap multiplications in parallel. The 13-bit results are added together in a single clock cycle and the result is stored in a 17-bit accumulator 611. The accumulator 611 is large enough that no overflow will occur. The resulting sum is then saturated to the most negative or most positive 8-bit value if necessary or else rounded to the nearest 8-bit value by an 8-bit limiter/rounder 613. The 8-bit result is latched into one of four output latches 615, 617, 619, 621.
It can be seen that the hardware of FIG. 12 performs a convolution every A/D sample period and the logic is structured to alternate between the I and Q channels. Pairs of I,Q outputs alternate between the punctual and early/late processing channels. Thus there are a total of four output latches 615, 617, 619, 621 each clocked by a different phase φ3, φ4, φ1, φ2 of the chip clock. Each chip clock phase is offset in time from another by one fourth of a chip period, as can be seen in the timing diagram of FIG. 11. The sequence of operations performed in one chip clock period are labeled in numerical order in FIG. 11. The labels are defined below:
SEQUENCE OF OPERATIONS
1. Select real coefficients while 2× Chip Clock is low
2. Shift in a new A/D sample 502 on the rising edge of 4× Chip Clock 410
3. Compute convolution of delay line 603 with real coefficients
4. Latch Punctual I output 518 on rising edge of Chip Clock φ1
5. Select imaginary coefficients while 2× Chip Clock 703 is high
6. Shift in a new A/D sample 502 on the rising edge of 4× Chip Clock 410
7. Compute convolution of delay line 603 with imaginary coefficients
8. Latch Punctual Q output 520 on rising edge of Chip Clock φ2
9. Select real coefficients while 2× Chip Clock 703 is low
10. Shift in a new A/D sample 502 on the rising edge of 4× Chip Clock 410
11. Compute convolution of delay line 603 with real coefficients
12. Latch Early/Late I output 519 on rising edge of Chip Clock φ3
13. Select imaginary coefficients while 2× Chip Clock 703 is high
14. Shift in a new A/D sample 502 on the rising edge of 4× Chip Clock 410
15. Compute convolution of delay line 603 with imaginary coefficients
16. Latch Early/Late Q output 521 on rising edge of Chip Clock φ4
The signals 519, 521, 518, 520 from the I and Q output latches 615, 617, 619, 621, respectively, drive the early, punctual and late (real and imaginary) channel processors 507, 509, 511 as shown in FIG. 13. The structure of the PN sequence generator 513 depends on the type of code implemented but is typically constructed with shift registers and Exclusive-Or gates. The PN sequence generator 513 is clocked at the chip rate, but is delayed in increments of one fourth of a chip period before being connected to each successive despreader and drives the early I channel despreader 505-1 directly. The PN sequence is delayed by one fourth of a chip period before driving the early Q channel despreader 505-2 since the Q channel is computed T c /4 seconds later than the I channel. It can be seen that if the PN sequence is delayed an additional Tc/4 seconds before driving the next despreader in sequence, that the proper timing relationships are maintained for an early/late delay locked loop with timing offsets of ±T c /2 relative to the punctual channel. Additional control logic is required to shift the relative timing phase of the PN sequence in increments of T c /2 during code acquisition. Once acquisition is achieved, the PN timing is fixed and timing tracking is accomplished through the sample timing phase control signal 418.
The despreaders 505-1 . . . 505-6 are each actually eight parallel Exclusive-Or gates 803 which either invert the data or not depending on the state of the PN sequence. The despread outputs are summed in 16-bit accumulators 805. The accumulated sums are latched in tri-state output latches 801 and every data symbol clock (i.e. for one complete period of the PN sequence). The accumulators 805 are also cleared on the same edge of the symbol clock. An accumulator width of sixteen bits is sufficient for spread factors up to 256 without any possibility of overflow. For larger spread factors, scaling and saturation logic must be incorporated into each accumulator. The six output latches 801 can be made addressable so that they can be read over a common data bus.
A method and apparatus to perform ideal matched filtering of a spread spectrum signal, assuming that the transmit signal has a square-root raised cosine response, has been outlined. The method may also be used for cases where matched filtering is not required or necessary. For example, if the spread spectrum transmit signal is unfiltered or is filtered with a full raised cosine filter response, the polyphase receive filter can have any desired lowpass response. The chip detection process will not be ideal since the polyphase receive filter impulse response is not matched to the transmit spread spectrum signal, but in many cases the loss is less than 1 dB. In addition, the number of filter taps for an equi-ripple lowpass filter is often much less than that required for a square-root raised cosine filter.
For example, consider the case of a transmitter employing a 20% full raised cosine transmit filter after the spreading operation. A polyphase lowpass receive filter can be designed with the characteristics shown in Table 4.
TABLE 4______________________________________Polyphase Equi-ripple Lowpass Filter Characteristics______________________________________Filter Type LowpassFilter Length 88 tapsSampling Frequency 32 R.sub.cQuantization: 9 bitsPassband Edge: R.sub.c/2Nominal Gain 1.00Maximum Passband Ripple 0.0778 dBLower Stopband Edge 1.54 R.sub.cUpper Stopband Edge 16 R.sub.cMinimum Stopband Attenuation -51.66 dB______________________________________
Although the filter is not matched to the transmit signal, it still serves to make digital timing corrections and also bandlimits the noise spectrum prior to despreading. The number of taps has also been significantly reduced and the number of hardware multipliers required for the filtering operation can be reduced from ten to six. The estimated loss in bit error performance for such a receiver structure is less than 1 dB.
The preferred embodiment just described, directed to a single-channel implementation, is readily applicable to another preferred embodiment, which is a multi-channel implementation, yielding a very efficient implementation of a multi-channel direct sequence spread spectrum CDMA receiver. The need for such an implementation can be appreciated with reference to the following.
In a CDMA communications system, many portable or mobile transmitters may transmit on the same frequency channel, each with a unique PN spreading sequence. Often, many geographically separate CDMA transmitters will transmit to a central receiving location such as a CDMA cellular base station or satellite earth station, for connection to the public switched telephone network. In a typical central receiving site, a separate receiver is required to receive each CDMA transmission.
Consider, for example, a typical prior art CDMA receiving system, where it is desired to receive up to M distinct CDMA channels per carrier frequency channel, as shown in FIG. 14. It is assumed that the chip timing frequency and phase of each CDMA transmission are not synchronous, but rather, each remote CDMA transmitter uses its own locally generated chip clock which may have a maximum error tolerance of 1 part per 10 -4 . A chip-synchronous CDMA network requires greater complexity and thus higher system costs, especially in a satellite system where the transmission delays can vary more greatly because of the diverse geographic locations of the CDMA transmitters.
In FIG. 14, a spread IF signal 214 is sampled by M A/D converters 301. Each A/D converter receives a steered sample clock 314 from a steered clock generator 302. Each sampled signal is then downconverted to baseband and despread. Note that M distinct A/D converters and steerable clock generators are required because of the asynchronous chip timing of each CDMA channel. However, as shown in FIG. 15, representing a multi-channel embodiment of the invention, the spread IF signal 416 is despread by a single L-bit A/D converter 901 and receives a sample clock from a single free-running sample clock generator 412. The A/D converter 901 may require additional bits of resolution because of the additional dynamic range resulting from multiple CDMA carriers residing on the same frequency channel; hence the designation of the A/D converter 901 as L-bit. The applicability of the invention to cellular radio communications, and the attendant dynamic range issue presented by that application, also makes it wise to use an L-bit A/D converter, where L is greater than 4. The number of bits of resolution shall be denoted as L. However, in most applications, L is between 6 and 12 bits, so that the L-bit A/D converter 901 is easily realizable in a single low-cost IC with current technology. The sampled signal may then be processed by a multi-channel digital downconverter/despreader/polyphase filter 902, which can be implemented quite efficiently in a single device with modern VLSI integrated circuit technology.
It is possible to posit a relationship of sorts between L and M. In general, as M quadruples in value, one more bit of resolution in the A/D converter is necessary, so L would increase by 1. For example, in the single channel case, M=1. Assuming L=4 were sufficient (based on the discussion of the previous embodiment), then if M=4, L should be 5; if M=16, L should be 6; and so on.
In fact, the M-channel polyphase filter 902 embodiment is very similar to that of FIG. 12, but the number of computations increases by a factor of M; in the disclosed embodiment processing is done M times faster, but an alternative would be to provide additional hardware. Refer to FIG. 16 for details of the hardware implementation. An L-bit A/D sample 905 is shifted into a polyphase filter delay line 929 at the sample rate of four times the chip rate, as in the single channel case. The polyphase filter also has 10 taps as in the single channel case, but multipliers 906 compute 9×L-bit products, and accumulator 908 has a width of 13+L bits to prevent overflow. The coefficients are stored in ten arrays of 16×9 static RAM 907 which can be downloaded over an external 9-bit bus 921. The filter coefficients are the same as those used in the single channel case and may have an impulse response matched to the pulse shape of the transmitted chips.
A modulo 2M counter 915 is clocked at a rate of 4M times the chip rate and is used to identify the current channel number, I. The output of the counter 915 is used to address a control RAM 914, which contains 4-bit values used to address one of the banks of filter coefficients. The width of the address but 928 is therefore log 2 M+1. The 4-bit output of the RAM 914 selects the appropriate filter bank to use for channel I. The MSB of the RAM output selects either the real or imaginary coefficients, and the 3 LSB's select one of 8 timing phases. A control bus 904 from a DSP processor is used to load the contents of the RAM 914 with the 4-bit values mentioned above. Because of the asynchronous nature of the timing for each channel, the I output may be computed for some channels, while the Q output may be computed for other channels during the same phase of the 4× chip clock controlling the delay line 929. Similarly, the early/late and punctual outputs for each channel will occur during different phases of the 4× chip clock. However, after the modulo 2M counter 915 has cycled through all 2M counts twice, both I and Q outputs will have been computed for all M channels. A bank of M delay locked loops in the DSP processor 903 is used to control the timing phase adjustments. When the timing for the i'th channel requires adjustment, the I and Q locations of the i'th channel in the RAM are written over the control bus 904 to indicate the proper coefficients to select. Note that, for a given state of the delay line 929, either the I or Q component is calculated. The control RAM 914 thus stores a coefficient address for both the I and Q components. The state machine then can sequence through the control RAM 914, and I and Q coefficients are automatically selected in the proper sequence.
One 13+L-bit results is computed in the accumulator every cycle of the 4M×chip clock. The resulting sum is then saturated to the most negative or positive 8-bit value if necessary or else rounded to the nearest 8-bit value by limiter/rounder 909. The final result is latched in output latch 910. Finally, a new A/D sample is shifted into the filter delay line 929 and the operation is repeated. Control logic 916 includes a state machine which controls the clocking of the major functional blocks 929, 907, 908, 909, and 910 of FIG. 16. In addition, the state machine 916 determines the state of each output 917 (i.e., early, punctual, late/I, Q).
Output latch 910 performs the functions that latches 615, 617, 619, and 621 perform in the embodiment of FIG. 12. Note that the clock input to output latch 910 is 4M×chip clock, whereas the various phases of the chip clock (chip clock φ1-φ4) are input into the latches 615, 617, 619, and 621. Thus, the data is dealt with one item at a time with a faster clock (irrespective of the factor of M), and the latch 910 provides timed outputs accordingly.
In addition, state machine 916 controls the multi-channel despreader hardware shown in FIG. 17. The length N PN sequences for M channels are stored in a M·N×2-bit static RAM 925. The MSB of the RAM 925 contains the PN sequences for the early and punctual channels. The LSB of the RAM contains the PN sequences delayed by one chip for use in the late despreading operations. On each cycle of the 4M×chip clock, the output signal 917 is routed to the despreader 930. The state machine logic 916 addresses the proper PN sequence bit of RAM 925 and also selects either the punctual/early or the late PN sequence through multiplexer 936. The state machine simultaneously addresses one of 6M 16-bit registers from register file 932. The register file contains the current accumulated despread sum for all M channels for early I/Q, punctual I/Q, and late I/Q results. The sum for the proper channel is loaded into the 16-bit accumulator 931. Then the 8-bit data from the output latch 917 is exclusive OR'ed with the selected PN sequence bit and the result is accumulated in accumulator 931. The sum is stored back into the same register previously read in register file 932. A register in the register file is cleared when the first bit of the PN sequence is detected, thus beginning the start of a new data symbol. Note that when an early/late sample is present in output latch 910, two despreading operations are required. First, the early/late sample is despread with the early PN sequence bit (MSB of RAM 925) and then on the next cycle the sample is despread with the late PN sequence bit (LSB of RAM 925).
Thus, the sequence of events is that the despreaders accumulate/despread one chip at a time for each channel and then proceed to the next channel. When the end of the PN sequence is reached for a given channel, the result is written into a 6M×16-bit dual-port RAM 934. The result is held in the dual port RAM 934 for an entire symbol period and can be read at any time over the DSP data bus 935 by DSP 903. The state machine logic 916 contains M status flags which indicate which of the M channels have data available to be read in dual port RAM 934.
Normally, the state machine logic 916 advances the PN sequence one bit at a time for each channel. However, whenever the PN chip timing is advanced across a sample boundary for a given channel, the state machine 916 skips one PN sequence location of the RAM 925. Thus, one despread symbol will consist of the sum of N-1 chips instead of the usual N. Similarly, to retard the PN chip timing across a sample boundary, the state machine 916 will repeat a bit of the PN sequence. Thus one despread symbol will consist of the sum of N+1 chips instead of the usual N.
It should be noted that the hardware implementation of the multi-channel embodiment just described differs to some extent from the hardware implementation of the single-channel embodiment described earlier. The inventor has determined that, at least in the multi-channel case, it is possible to perform the despreading function, and obtain the complex data symbol, and the complex early/late timing signals, with a single delay rather than two delays.
While some of the details have been omitted for simplicity, those details are well within the abilities of the ordinarily skilled artisan to implement. It should be noted that the efficiency of the multi-channel implementation is greatly enhanced through the use of a single A/D channel and an efficient polyphase filter structure which inherently can track the timing phase of M individual receive CDMA channels. The magnitude of M is limited primarily by the speed of the digital hardware used. Greater values of M are possible through greater use of parallelism by implementing multiple polyphase filter and despreader hardware blocks.
In light of the above teachings, many modifications in variations of the present invention are possible. It should be understood, therefore, that the principles of the present invention may be realized in embodiments other than as specifically described herein.
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A system for digitally downconverting and despreading a multi-channel analog direct sequence spread spectrum signal is provided. The system includes a free-running, non-steering, clock generator which outputs an A/D sample clock, and an A/D sample clock having a rate which is an integral multiple of a chip rate of the spread spectrum signal. An A/D converter which receives the spread spectrum signal and the A/D sample clock and outputs a digitized multi-channel signal from the multi-channel spread spectrum signal, and a local pseudo-noise sequence signal source which outputs M local pseudo-noises, wherein M is an integer greater that 1 is also included. A multi-channel complex downconverter/polyphase filter which receives the digitized multi-channel signal and the A/D sample clock and a sample timing phase control signals, simultaneously filters and downconverts the digitized multi-channel signal to baseband, corrects timing phase misalignment between the digitized multi-channel signal and the locally generated pseudo-noise sequences, and outputs a multi-channel complex corrected baseband signal is provided.
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BACKGROUND OF THE INVENTION
1. FIELD OF THE INVENTION
The present invention relates to a thermal fuel level detector capable of detecting the level of fuel remaining in a fuel tank of an automobile or the like.
2. RELATED ART STATEMENT
Previously, most fuel level detectors of the type described above comprises a slide-content type potentiometer attached to an end of a fuel level float. A conventional structure in which such a potentiometer is employed experiences a problem of contact damage therein due to the presence of sulfides or other fuel additives since the contact thereof is exposed to fuel or steam. It is difficult to keep the conventional structure providing accurate slide-resistance values for a long time.
Another problem is experienced with the conventional structure in that it is difficult to obtain a resistor with a shape which corresponds to the shape of a fuel tank, causing a large error in detection of a fuel level.
Although various methods have been devised in order to overcome the above-described problems, none has yet been put into practice due to cost and performance drawbacks. For example, a liquid level sensor disclosed in Japanese Patent Laid-Open No. 59-148826 and structured such that thermistor layers are formed in order on a rod-like or an elongated insulating material can relatively accurately detect the liquid level under certain temperature conditions. However, since thermistors do not exhibit linear resistance changes with respect to temperature changes, such liquid level sensors cannot accurately detect a continuous change in liquid level where the temperature of either the liquid or the ambient changes even if a temperature compensating sensor is additionally provided. Thermistors further experience a problem of insufficient protection against gasoline containing sulfides, more particularly against light oil. Therefore, such liquid level sensors cannot be used as a fuel level detector for an automobile.
Furthermore, the Nippon Denso Publication Technology Monogram (No. 48-101, published on July 15, 1986) discloses a system formed, as shown in FIG. 1, such that: one of two metal wires made of the same material and having the same temperature resistance coefficient is arranged to be a self-heating sensing resistance wire 40, with the other of the wires being arranged to be a temperature compensating resistance wire 41; the self-heating sensing resistance wire 40 is in part dipped in liquid fuel; external resistors 42 and 43 whose resistance values are equal are used with the former to form a bridge circuit; a potential difference between junctions 44 and 45 is amplified by a differential amplifier 46 to detect a difference in temperature between the self-heating resistance wires corresponding to said potential difference, so that the liquid level is detected. However, this system involves two serious problems. First, since the temperature compensating resistance wire 41 is disposed in the part of the fuel tank in which the same is not dipped in the liquid fuel, although a correction to compensate a change in ambient temperature, a correction cannot be made to compensate a change in temperature of the liquid fuel. Secondly, since metal wires are used, the resistance value per unit length of the same becomes excessively low even if the diameter of the wire is made as small as possible while still ensuring the strength of the metal wire. This leads to a problem in that the power consumption by the above-described system imposes a high load on a car battery which is used as the power source of this system. Therefore, such a system cannot be put into practical use.
SUMMARY OF THE INVENTION
To this end, an object of the present invention is to provide a fuel level detector which can accurately detect a fuel level with a reduced power consumption exhibiting an improved reliability regardless of the ambient and liquid fuel temperatures in order to overcome the problem of contact damage involved in a thermistor or a metal wire type system.
In order to overcome the above-described problem, the present invention is characterized in that a self-heating sensing resistor having a relatively high temperature resistance coefficient is formed on a substrate so as to detect a change in the resistance value of the sensing resistor due to cooling caused by heat of vaporization along a portion of the sensing resistor 20 which is dipped in fuel, as a differential output voltage. A temperature compensating resistor is provided on the substrate, for compensating the differential output voltage for ambient temperature in the fuel tank in order to prevent an error in the differential output voltage.
According to the present invention, since the self-heating sensing resistor which can radiate heat when it is energized and the temperature compensating resistor are formed to have equal lengths, and since each of the above-described two temperature compensating resistors comprises a film resistor made of platinum, gold, silver, palladium, ruthenium oxide, copper, nickel, steel or an alloy thereof, the fuel level can be accurately detected even if the ambient temperature and/or the temperature of the liquid fuel in the fuel tank is changed.
Furthermore, since the self-heating sensing resistor and the temperature compensating resistor are formed respectively of film resistors, the resistance value per unit length can be increased in comparison with the case of the metal wire. Therefore, a temperature detecting fuel level detector exhibiting reduced power consumption and having a practical advantage can be obtained.
Furthermore, a further accurate, high sensitive, reduced cost temperature detecting fuel level detector can be obtained in the case where the above-described temperature detecting resistor film is formed by a plating process or by baking the coated and printed metallo-organic substance, or in the case where the above-described temperature detecting elements are formed in a chip shape and the thus-formed chip-shaped temperature detecting elements are mounted on a substrate made of epoxy glass, polyethylene telephthalate (PET), polyester, polyimide, denatured of the former materials, polyparabanic acid, an aramid film, bismuthreimide triazine resin (manufactured by Mitsubishi Gas Chemical Industries Ltd.), Bectra (manufactured by Poly Plastic), polyacetal, glass, or the like.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a circuit diagram for use in a conventional fuel level detector comprising metal wires;
FIGS. 2A and 2B are plan views which illustrate detection portions for use in a fuel level detector according to an embodiment of the present invention;
FIG. 3 is a perspective view which illustrates a state where the detection portions are disposed in a fuel tank;
FIG. 4 is a circuit diagram for use in the fuel level detector;
FIG. 5 is a plan view which illustrates a detection portion of a temperature detecting fuel level detector in which a self-heating sensing resistor 3 and a temperature compensating resistor are formed on one insulating substrate;
FIGS. 6A and 6B are plan views which illustrate a detection portion of a temperature detecting fuel level detector formed by mounting temperature detecting resistor chips on a substrate;
FIG. 7 is a plan view which illustrates a detection portion of a temperature detecting fuel level detector for detecting in a digital manner the liquid level by connecting the self-heating sensing resistors in parallel;
FIG. 8 is a circuit diagram for use in the detector shown in FIG. 6;
FIG. 9A is a view which illustrates the characteristics of the differential output voltage which can be generated from bridge circuits formed such that both of the temperature detecting resistors are dipped in fuel;
FIG. 9B is a view which illustrates the characteristics of the differential output voltage which can be generated from bridge circuits formed such that one of the temperature resistors is exposed to air.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
First Example
FIGS. 2A and 2B are views which illustrate the structures of the pattern of a temperature detecting resistor disposed in a detection portion of a fuel level detector according to an embodiment of the present invention. Referring to FIG. 2, reference numeral 1 represents an insulating ceramic substrate. Reference numeral 2 represents an SiO 2 -Al 2 O 3 --B 2 O 3 group underglazed glass having a softening point of 920° C. with which the ceramic substrate 1 is coated. Reference numeral 3 represents a self-heating sensing resistor having a high temperature resistance coefficient and formed on the underglazed glass 2 by means of printing and baking. Reference numeral 4 represents a temperature compensating resistor made of the same material as that of the self-heating sensing resistor 3, and having substantially equal lengths. According to this embodiment, platinum metallo-organic paste obtained by adding a binder such as resin acid, its modified form or adding the like to a platinum salt of sulfide or mercaptide of dimer to pentmer of terpenes is used to print a desired pattern before it is baked at 900° C., whereby a platinum thin foil temperature detecting resistor body having a thickness of substantially 4,000 Å is formed. The self-heating temperature detecting resistor body exhibits a resistance value of 20 Ω at 0° C., while the temperature compensating resistor exhibits a resistance of 5 kΩ at the same temperature, and the above two types of resistors exhibit equal temperature resistance coefficients of about 3,700 ppm/° C. Reference numeral 5 represents an output electrode having a relatively low conductor resistance and made of, according to this embodiment, silver palladium (substantially 15 μm in thickness).
The above described temperature detecting resistors 3 and 4 and the electrode 5 are coated with a borosilicate lead group overcoat glass film 6 as a protection coating for the purpose of providing oil resistance, chemical resistance, and insulation.
FIG. 3 is a view which illustrates an example wherein a pair of elements consisting of a first temperature detecting element 7 including the self-heating sensing resistor and a second temperature detecting element 8 including the temperature compensating resistor are disposed in a fuel pump unit 9 provided in a fuel tank. These elements are electrically connected to each other through a circuit shown in FIG. 4. Referring to this drawing, reference numeral 11 represents the detection portion shown in FIG. 2, which comprises the self-heating sensing resistor 12 and the temperature compensating resistor 13 shown in FIG. 2. These resistors are connected to the corresponding resistors 14 and 15 whereby resistance bridge circuits are formed.
The outputs of these bridge circuits are connected to the corresponding inverting input terminal and a non-inverting input terminal of an operation amplifier 16 via the corresponding resistors 17 and 18, this operation amplifier 16 forming a differential amplifier circuit. Reference numeral 19 represents a resistor.
That is, in the above described circuit, the resistance value of the sensing resistor 12 which undergoes heating at a predetermined voltage or a predetermined current, varies depending upon the fuel level. Such change in resistance value is inputted as a change in the potential at the output of the bridge circuit, to the differential amplifier circuit. This differential amplifier circuit outputs at the output terminal thereof any difference in voltage so that any change in the fuel level can be outputted as a change in voltage.
Furthermore, since the temperature compensating resistor 13, is thermally separated from the self-heating sensing resistor 12, the heat which has been spontaneously given by the self-heating sensing resistor 12 is prevented from being transmitted to the temperature compensating resistor 13.
Therefore, since the temperature compensating function of the temperature compensating resistor 13 with respect to the ambient temperature in the gasoline tank can be properly effected, an accurate fuel level detection can be achieved.
Similarly to this embodiment, a metallic organism of gold, silver, ruthenium, and palladium may be used to form a metal or metal oxide thin film which can serve as a temperature detecting resistor. Although the self-heating sensing resistor and the temperature compensating resistor are formed on individual substrates according to this example, they may, as shown in FIG. 5, be formed on one and the same substrate if necessary.
EXAMPLE 2
Paste preparated by mixing a nickel metallic organic substance such as nickel octanate and ferrous metallic organic substance such as octylic acid salt of steel at a 9:1 ratio, and then by adding modified resin or the like as a binder, is used to form the self-heating sensing resistor and the temperature compensating resistor shown in FIG. 2 by means of screen printing. The thus-printed paste is baked in air at 620° C., and then baked for deoxidation at 550° C. in a deoxidation atmosphere, whereby a nickel-steel thin film substantially 2,000 Å thick and exhibiting a temperature resistance coefficient of substantially 4,500 ppm/° C. is obtained. Then, a temperature detecting element prepared by applying a borosilicate overglass coating to the above nickel-steel thin film at 600° C. in an atmosphere of nitrogen is used similarly to the example 1.
Also similarly to this example, a copper metallic organic substance may be used to form a copper thin film which can serve as a heated sensing resistor.
Example 3
Since the self-heating sensing resistor and the temperature compensating resistor shown in FIG. 2 are formed by a nickel boron thin film obtained from an electroless nickel boron plating, the nickel boron thin film can be aged under heat by forming borosilicic overcoat glass at 600° C. in an atmosphere of nitrogen, causing the sintered tightness to be improved. As a result, a nickel boron thin film having a thickness of substantially 2,500 Å and exhibiting a temperature resistance coefficient of 4,200 ppm/° C. is formed.
If necessary, electric plating may be applied.
Then, also the thus-formed temperature detecting element can be used in a manner similar to that of Example 1.
Similarly to this example, a resistance thin film serving as a heated sensing resistor may be made of platinum, gold, silver, palladium, copper, chrome cobalt, steel, or an alloy thereof.
If the temperature resistance coefficient of the self-heating sensing resistor and that of the temperature compensating resistor are equal, an ideal fuel level detection can be conducted. However, it is difficult for the two temperature resistance coefficients to be made equal to each other in practice. In terms of the practical use, no problem is presented if the difference between the above two coefficients is 500 ppm/° C. or less. This leads to a result that the material for the self-heating sensing resistor and the material for the temperature compensating resistor do not need to be the same. However, it is preferable for the temperature compensating resistor to have a length equal to that of the self-heating sensing resistor. However, this does not apply to a case where the lengths of both resistors cannot be equal to each other.
Example 4
FIGS. 6A and 6B are views which illustrate a detection portion of the fuel level detector according to another example of the present invention.
Referring to FIG. 6, reference numeral 20 represents a 50 μm thick substrate made of a polyimide film, with a conductor 21 having a predetermined circuit pattern being formed on this substrate 20. Reference numeral 22 represents a self-heating platinum sensing resistor chips obtained from the following steps: platinum metallo-organic paste is printed on an underglazed forsterite substrate before it is baked at 900° C.; electrode paste which mainly contains silver is printed in the form of primary electrodes; such printed primary electrodes are baked at 600° C., and borosilicic lead overcoat glass is layered thereover. The thus-prepared chips exhibit a temperature resistance coefficient of 3,700 ppm/° C. and a resistance value of 1.0 Ω at 0° C. Reference numeral 23 represents a temperature compensating platinum resistor chip which is prepared by the same method as that for the self-heating sensing resistor chips, and which exhibits a temperature resistance coefficient of 3,700 ppm/° C. and a resistance value of 50 Ω at 0° C. A fuel level detection exhibiting an excellent thermal response and improved accuracy can be conducted by employing the thus-formed self-heating sensing resistor and the temperature compensating resistor with both being connected to a circuit similar in that shown in FIG. 4, in a manner similar to that of Example 1.
Although the self-heating sensing resistor chips and the temperature compensating resistor chips are mounted on individual substrates in this example, the above two kinds of chips may be mounted on one and the same substrate. As an alternative to the temperature compensating resistor comprising a group consisting of resistors in the form of chips in this example, a temperature compensating resistor formed, as shown in FIG. 2B, on a ceramic substrate may be employed.
Example 5
FIG. 7 is a view which illustrates the pattern of the sensing resistor in the detection portion of the fuel level detector according to another example of the present invention. Referring to FIG. 7, reference numeral 24 represents a ceramic substrate. Reference numeral 25 represents thin elongated film shaped self-heating sensing resistors exhibiting a relatively high temperature resistance coefficient and formed on the ceramic substrate 24 by printing and baking, wherein these resistors comprise thin film platinum resistors 4,000 Å thick obtained by baking platinum metallic organic paste in air at 900° C. and exhibit a temperature resistance coefficient of 3,700 ppm/° C. The thus-obtained thin wire shaped sensing resistors 25 are arranged in a plurality of stages in parallel to the fuel surface in a fuel tank. According to this example, 13 sensing resistors 25 in total are formed at the positions which divide the quantity of the remaining fuel into 12 portions. Although the sensing resistors are arranged to be in parallel to the fuel surface in this example, they may be arranged at a predetermined angle with respect to the fuel surface, if necessary. The thus-arranged sensing resistors 25 are connected through thick film-shaped electrodes 26 (having a mean thickness of substantially 15 μm) made of silver palladium and exhibiting a relatively low conductor resistance, whereby a parallel resistor circuit is formed. Reference numeral 27 represents output electrodes disposed at end portions of the sensing resistors 25. Chip resistors 29 exhibiting a relatively low temperature coefficient are mounted on output electrodes 27, and a flexible substrate 31 on which signal lines 30 are formed on the reverse side thereof, signal lines 30 are connected to output electrodes 27 via the through holes 32 by soldering for the purpose of detecting a change in the differential output voltage. Furthermore, the sensing resistors 25 and the electrodes 26 are covered thereover with a borosilicic lead overcoat glass film 28 for the purpose of providing oil resistance and chemical resistance.
FIG. 8 is a view which illustrates a circuit for use in the fuel level detector in which the detection portion shown in FIG. 7 is employed. Referring to this figure, reference numeral 33 represents a detection portion. Twelve self-heating sensing resistors 34 which are connected in parallel to each other and resistors 36 which are connected in series to sensing resistors 34 and which exhibit a relatively low temperature resistance coefficient respectively form resistor bridge circuits in association with a sensing resistor 35 disposed at the lowermost position of the detection portion 33 and resistors 37 which are connected in series to sensing resistor 35. The sensing resistors 34 and 35 exhibit substantially equal temperature resistance coefficients, and preferably, they have the same resistance values.
The output ends of these bridge circuits are respectively connected to inverting input terminals and non-inverting input terminals of an operation amplifier 38 forming a differential amplifier circuit.
That is, according to this circuit, the bridge circuit formed by an arrangement consisting of the sensing resistor 35 which is always dipped into fuel and exhibits a small change in resistance value due to its self-heating characteristic and the one of the sensing resistors 34 which is dipped in fuel does not output any differential output voltage as shown in FIG. 9A. However, the bridge circuit formed by the sensing resistor 35 and the sensing resistors which are exposed to air instantaneously outputs a differential output voltage as shown in FIG. 9B. The thus-outputted differential output voltage is amplified by the operation amplifier 38, and then the number X of the sensing resistors from which no differential output voltage was outputted is counted by an arithmetic portion 39.
If X is, for example, 5, the remaining fuel is 5/12 of the fuel capacity of the fuel tank.
Thus, the fuel detection is conducted. In the temperature detecting fuel level detector according to the present invention, a detection is made only as to whether or not a differential output voltage is generated, and the absolute value of the differential output voltage is not detected intact. Therefore, fuel levels can be instantaneously obtained, and accordingly, no waiting is required until the differential output voltage is stabilized. Furthermore, due to the thus-improved responsibility, electricity need not always be supplied to this temperature detecting fuel level detector. For example, the fuel level can be detected simply by supplying an operation voltage Vcc or a predetermined current I at two minute intervals. As a result, the power consumed by the temperature detecting fuel level detector according to the present invention can be significantly reduced, and in addition, the relability of the detecting element can be improved.
In this embodiment, although a fuel level is detected by making a comparison between the sensing resistors which are always dipped into fuel and the other resistors the fuel level may be detected by making a comparison between the sensing resistors which are always exposed to air and the others.
Furthermore, according to this embodiment, chip resistors are employed to serve as the resistors having a relatively low temperature resistance coefficient. As an alternative, it may be formed on the ceramic substrate by printing and baking a glazed resistor made of ruthenium oxide.
As described above, according to the present invention, sensing resistors each capable of indicating a fuel level which corresponds to the shape of the fuel tank are arranged in a pattern, and therefore a fuel level is accurately detected. In addition, the fuel level in different shaped fuel tanks can be readily detected. In addition, a significantly improved response to the temperature detection at an arbitrary fuel level can be obtained by positioning the self-heating sensing resistor and the temperature compensating resistor so as to be thermally isolated from each other. Even if the ambient temperature in a fuel tank is varied, the correction can be automatically conducted, and since the fuel detector according to the present invention is of a temperature detecting type, a detection can be conducted without any occurrence of significant differences with respect to the kinds of gasoline. Furthermore, since the sensing resistor is coated with overcoat glass which exhibits improved tightness and stability, it can maintain its reliability and quality for a long time even if the same is dipped in fuel containing an additive such as alcohol or sulfide. If a plating method or metallic organic paste is employed, a desired thin film pattern of the sensing resistor can be readily formed by means of printing and baking. Therefore, no material loss occurs, and an etching process inevitably associated with a spattering method is obviated, resulting in improved manufacturing yields and reduced costs.
In addition, a temperature detecting fuel level detector formed by mounting chip-shaped temperature detecting elements on a substrate made of, for example, epoxy glass can be readily obtained since a large-sized fuel tank having a substrate of 50 cm in length is available. Further, the substrate can be obtained at a cost lower than that of a ceramic substrate and the detection speed can be increased, due to its relatively small thermal capacity. Consequently, a significant advantage can be obtained in the subject industry.
As described above, according to the present invention, the sensing resistors each capable of indicating a fuel level which corresponds to the shape of a fuel tank are arranged in the pattern, and therefore a fuel level can be accurately detected. In addition, the fuel level in a different shaped fuel tank can be readily detected. Consequently, a significant advantage can be obtained in the subject technical field.
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Provided is a fuel level detector for use in a fuel tank of an automobile or the like which can accurately detect a fuel level with a reduced power consumption exhibiting an improved reliability regardless of the ambient temperatures and the temperatures of liquid fuel in order to overcome the problems involved in a thermistor method and a metal wire method. A spontaneously heated sensing resistor having a high temperature resistance coefficient is formed on a substrate so as to detect a change in the resistance value due to cooling by heat of vaporization at a portion of the sensing resistor which is dipped in fuel as a differential output voltage. In order to prevent errors in the differential output voltage due to the correction of the ambient temperature in the fuel tank, a temperature compensating resistor is provided on the substrate.
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FIELD OF THE INVENTION
This invention lies in the field of pavement markers which are equipped with installation tabs.
BACKGROUND OF THE INVENTION
Pavement markers which have convexly rounded upper surface portions and convexly extending perimeters have come into general usage particularly for use in vehicular lane marking. For example, by placing a series of markers upon the center line of a two-lane paved road with the markers being longitudinally spaced from one another, improved ability is provided for a vehicle driver to stay in his assigned proper lane is provided. A vehicle driver traveling in either direction either sees the markers or senses the vibration when tires of his vehicle strike individual markers successively. At least some of the pavement markers of a center line located series can each be associated with retro-reflective reflector means for viewability by approaching vehicle drivers during nighttime.
At the present time, pavement markers are installed manually. Each individual pavement marker of a series is positioned by hand and is conveniently adhered to a paved road surface at a desired location and oriented position by means of an adhesive. A presently commonly used adhesive is hot tar during installation.
The convexly rounded upper surface portions of a pavement marker cannot be held by an installer's hand since no gripping surface exists. For an installer to hand hold a pavement marker along opposed portions of its opposite edges is dangerous because of the potential for finger and/or thumb burns from exposure to the hot tar during final positioning and contacting of an individual pavement marker with freshly deposited hot tar during installation.
There is a substantial need in the art of pavement markers for a system or means for manually holding an individual pavement marker in such a way that the chance of injury to an installer's hand is substantially eliminated.
BRIEF SUMMARY OF THE INVENTION
This invention relates to pavement markers with generally convexly rounded upper surface portions which are initially provided with digitally graspable, integrally associated, frangible installation tab means.
The tab means permits an installer to use his hand safely to pick up, move, position and deposit such a pavement marker upon and into a localized deposit of hot tar or like adhesive at a site on pavement whereat the marker is to be located and installed.
After installation, the tab means is readily broken away at the rounded upper surface leaving only a slight, almost imperceptible imperfection thereon of no adverse consequence to the usage or the appearance of the resulting pavement marker.
A pavement marker that is so equipped with such tab means can have any desired or convenient number of tabs and any desired or convenient marker configuration. However, a present preference is to employ a pair of tabs and a pavement marker body having a convexly curved perimeter, and, most preferably, a round configuration. Also, an inventive pavement marker preferably has a generally planar bottom face which is provided with surface irregularities for augmenting bottom bondability to an adhesive.
A tab equipped pavement marker of this invention is also easily stored and shipped after manufacture and before installation because a plurality of such markers can be vertically stacked one on the other with the tabs functioning to stabilize the super adjacent marker and to prevent damage to markers by scratching or the like.
The generally convexly rounded upper surface of a pavement marker is preferably continuous in curvature except for areas thereof wherein a reflector means is optionally associated. Preferably, such a reflector means is retro-reflective and lenticular, and is inset into such rounded upper surface.
The body of a pavement marker is fabricated of relatively rigid moldable materials. Plastic, metal or ceramic materials are usable. A reflector if incorporated into a marker is fabricated of transparent plastic.
A preferred pavement marker of this invention has a solid body that is equipped with either one or two inset retro-reflective lenticular reflector.
Other and further objects, aims, purposes, features, advantages, embodiments, variations and the like will be apparent to those skilled in the art from the present teachings taken with the appended drawings and associated claims.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
FIG. 1 is a perspective environmental view showing one embodiment of a reflectorized pavement marker of the present invention that is being hand held and positioned over a dollop of hot tar;
FIG. 2 is a view similar to FIG. 1, but showing the hand held marker immediately after implacement against the hot tar;
FIG. 3 is another perspective view of the marker shown in FIGS. 1 and 2 but showing the marker after implacement and the installer's hand has been removed;
FIG. 4 is a top plan view of the marker shown in FIGS. 1-3;
FIG. 5 is a bottom plan view of the marker shown in FIGS. 1-4;
FIG. 6 is a greatly enlarged fragmentary perspective view taken in the region VI--VI of FIG. 3 showing the appearance of one presently preferred presently preferred installation tab;
FIG. 7 is a view similar to FIG. 4 but showing an alternative embodiment of a pavement marker; and
FIG. 8 is a view similar to FIG. 4 but showing another alternative embodiment of a pavement marker.
DETAILED DESCRIPTION
Those skilled in the art will appreciate that a pavement marker of this invention can have various desired configurations or shapes. However, a present preference is to employ a pavement marker whose body has a solid, opaque, flattened configuration. The body preferably has a generally continuously curved (or convexly rounded) upper portion and a generally convex perimeter which has an oval, or more preferably, circular configuration. Preferably also, the pavement marker body has a generally flattened or planar bottom face.
Referring to the drawings, there is seen in FIGS. 1-5 an embodiment 10 of a presently preferred pavement marker of this invention. The pavement marker 10 has a generally convexly rounded upper surface 11 whose facial curvature is preferably comparable to that of a spherical segment. Also, marker has a generally circular perimeter edge or side 12 which upstands somewhat from the periphery of a bottom face 13 and which extends at a slight upward inward angle of inclination (not shown in the drawings) relative to the pavement marker 10 central vertical axis 14 (shown as a point, for example, in FIG. 4). Such slight angle of side inclination can vary as desired, but is conveniently and preferably in the range of about 0.4° to about 2.5° with respect to the vertical. This inclination angle is provided not only to enhance the ease with which a vehicular tire (not shown) can commence a roll over surface 11, but also to enhance the ease of removal of a reflector body portion that includes the surface 11 and the integrally formed edge 12 from a mold. The corner 16 between the edge 12 and the surface 11 is preferably rounded or beveled (not shown in the drawings) for similar reasons.
Typically, the side 12 of a pavement marker 10 extends upwardly from the bottom 13 and the pavement surface 47 upon which marker 10 is mounted a short distance, and the rounded upper surface 11 is configured so that a vehicle tire readily rolls thereover. For example, maximum pavement marker 10 height is preferably along center axis 14 and this height is commonly and preferably in the range of about one to about three centimeters.
The diameter of a pavement marker 10 can vary. A present preference is to provide a diameter that is in the range of about 5 to about 15 centimeters, but larger and smaller radii can be employed, if desired. Preferably marker 10 has a solid body that defines the top surface 11, edge 12 and bottom 13.
Although pavement marker 10 has a generally flattened or planar bottom face 13, for ease of accurate mounting and adherence to adhesive means, the bottom face 13 is preferably provided with surface irregularities, such as an open waffle design or the like. To eliminate air entrapment and improve the adhesive bonding of the marker 10, the bottom face 13 is here preferably provided with a plurality of spaced, shallow, discretely formed projecting feet 17.
The generally convexly rounded upper surface 11 of pavement marker 10 is preferably continuous and preferably has a smooth or uniform curvature except for areas thereof which may be associated with reflector means. Reflector means is optionally incorporated into a pavement marker so that the pavement marker 10 is reflective, preferably retro-reflective, in response to incident light striking a pavement marker from approaching vehicular headlights at night.
While a reflector means that is associated with a pavement marker 10 can be located on, or recessed in, the rounded upper surface 11, it is presently preferred to have a lenticular prismatic retro-reflective reflector located in one or two localized areas of the rounded upper surface 11. When two such areas are provided, it is preferred that each be generally opposed to the other and located on opposite sides of the surface 11 of pavement marker 10 for retro-reflectivity in opposed directions. In general, when such a lenticular reflector is associated with a pavement marker 10 upper surface 11, the reflector is retro-reflectively effective within a predetermined small included vertical angle relative to and extending upwardly from the horizontal (or assumed) surface of the road), and also within a predetermined small included horizontal angle relative to either side of a hypothetical horizontal center line extending through a reflector perpendicularly to a reflector center line running across the planar face of such a reflector.
A planar-faced, prismatic, lenticular, reflex-reflective member as mounted in a pavement marker body preferably is retro-reflective of incident light originating within an effective projected vertical reflex angle that extends from about a horizontal ground line upwards to a maximum vertical angle that is not more than about 0.5 degrees and preferably is about 0.2 degrees. Also, such reflective lens-like member as so mounted is retro-reflective of incident light originating within an effective projected horizontal reflex angle that extends at least about 1 degree on either side of a horizontal line that extends perpendicularly through a center line that extends horizontally across the planar face of such member. In the case of pavement marker 10, this horizontal line corresponds approximately to a diameter of the body of marker 10.
Owing to the nature, structure, and operation of a prismatic lenticular retro-reflective reflector, it is common to achieve such retro-reflective viewability angles using a retro-reflective reflector which is comprised of clear plastic which has a flat (or planar) smooth front face behind which are positioned (by molding in clear transparent plastic) hexagonal retro-reflective elements. The nature and construction of such a flattened retro-reflective reflector element is well known in the art and lenticular reflectors incorporating such elements are believed to be commercially available. Such a retro-reflective reflector is preferably inset into the profile of the pavement marker top convex surface, and, as mounted in such surface, is canted or angularly inclined. Preferably such an inset reflector has perimeter portions which are overlapped slightly by adjacent portions of the top surface 11 for holding and sealing purposes. Preferably, the pavement marker body is opaque as distinct from the clear (transparent) body of the reflector itself. The reflector can also be colored such as yellow, red, blue, green or the like.
In a pavement marker 10, two flat retro-reflective reflectors 18 and 19 are utilized which are each inset into the upper surface 11 and located in symmetrical, opposed relationship to one another on diametrically opposed sides of center axis 14 between axis 14 and edge 12. Each reflector 18 and 19 is provided with a trapezoidal perimeter configuration with the respective elongated straight base 21, 22 being adjacent edge 12, and the respective elongated shorter straight apex 23, 24 being adjacent axis 14. The opposite side chords 26, 27 and 28, 29 of each respective reflector 18 and 19 are suitable for achieving the desired inset position of each reflector 18 and 19 relative to rounded upper surface 11 (see FIG. 4, for example).
Because the inclination angle of the front planar face of each reflector 18 and 19 is somewhat greater than the curvature associated with upper surface 11 in pavement marker 10, the base 21, 22 of each reflector 18, 19 is radially inset from the adjacent portions of edge 12. To avoid impairment of the desired horizontal vertical viewability angle for 32 each reflector 18, 19, the body region 31 and 32 between each base 21, 22 and adjacent portions of edge 12, respectively, is flattened and extends generally horizontally.
The body regions 33, 34 along and forwardly of each side chord 26, 27 and also the region 38 above the reflector 18, and the corresponding regions 36, 37 along and forwardly of each reflector side chord 28, 29 and also the region 39 above the reflector 19, are slightly angled (with respect to the vertical) so as not to interfere with reflector viewability. Beveled edges are preferably provided (not shown in the drawings) to provide a smooth adjoining inter-connections between such regions and the surface 11 and also the edge 12.
In accord with this invention, the generally convexly rounded upper surface of a pavement marker, such as pavement marker 10 or the like, is provided with tab means, such as a pair of upstanding tabs 41 and 42. In marker 10, tabs 41, 42 are each located and based preferably on the surface 11 so as to be in spaced, adjacent relationship to the edge 12 of the marker 10 and also to the center 14 of the marker 10. For reasons of easy balance when a marker 10 or the like is supported by such tab means, the pair of such tabs 41 and 42 is located preferably along or on either side of a (hypothetical) diametrical line (not shown) that passes through the approximate center 14 of the marker 10. In marker 10, this line preferably corresponds to a diameter that extends mid-way between the apexes 23 and 24 and also is perpendicular to another hypothetical diametrical line that extends perpendicularly through a facial center line on each of the respective reflectors 17 and 18.
The individual tabs of a marker, such as tabs 41 and 42, can have various configurations consistent with their desired moldability with upper surface 11. Preferably the tabs 41 and 42 are each unitarily molded and formed concurrently with the rounded upper surface 11 of a pavement marker 10 at the time of marker body formation.
For reasons of providing convenient, controllable frangibility or breakability of the tab means preferably at the bottom thereof adjacent surface 11 after pavement marker installation, it is now preferred to have each individual tab such as tabs 41 and 42 be uniformly elongated in tab width (relative to a diameter of marker 10) compared to tab breadth (relative to a circumference of marker 10) particularly at the location on the upper surface 11 where a tab upstands or projects. For reasons of moldability, such elongation in tab width preferably lies generally along a diameter in marker 10.
For reasons of providing digitally engagable tab outer end portions, each individual tab 41, 42 is preferably relatively blunt ended yet such outer end portions are preferably elevated above the rounded marker surface 11 to an extent such that an installer's hand 43 using only the forefinger tip and a thumb tip regions 46 and 44, respectively, can engage the outer end portion of each one of the pair of tabs 41, 42 of the pavement marker 10 and thereby support the marker 10 with compressive force exerted between the thumb and forefinger the marker 10 preferably without contacting the adjacent rounded surface portions 11 (see FIG. 1). Each tab 41 and 42, however, is also breakable adjacent top 11 responsive to a relatively small bending force applied against a top outer region in a different direction from that in which such compression force is exerted. In the marker 10, this bending force is exerted or applied preferably normally (that is generally circumferentially relative to the body of marker 10) in contrast to the direction the compression force is applied (that is, generally radially relative to the body of marker 10).
In place of a pair of tabs, such as tabs 41 and 42, a single tab 50 shown in phantom in FIG. 7 can be employed that is located, for example, across axis 14' on surface 11 and which is sized so as to be graspable by the thumb and forefinger of the installer's hand. Also, in place of tabs 41 and 42, three equally circumferentially placed tabs can each be employed, if desired (not shown) which can be contacted by individual ones of each of a thumb and two fingers for marker grasping, lifting and positioning purposes. Various tab means thus can be employed.
To install a pavement marker 10 upon a road pavement or the like, and in accord with usual contemporary commercial practice, one deposits at a predetermined location on pavement 47 a dollop 48 or quantity of hot, liquified tar. The amount of tar in the dollop 40 is preferably at least about sufficient to cover the bottom face 13. Such hot tar reportedly has a temperature in the range of about 190° to about 230° C. Before such tar dollop 48 has a chance to cool appreciably, the installer picks up a pavement marker 10 and holds same by and between the tabs 41 and 42 using the thumb and forefinger tip regions 44 and 46 of one hand 43. He then moves the so held marker 10 to a position over and adjacent to the tar dollop 48, and he orients this marker 10 with his hand 43 so that the marker 10 and its reflectors 18 and 19 are positioned and oriented as desired, as shown in FIG. 1. He then deposits the marker 10 upon the hot tar dollop 48 and preferably pushes downwardly to impress the bottom face 13 and feet 17 into the dollop 48 as shown in FIG. 2. Finally, he releases the marker 10 from his hand 43 before heat from the tar dollop 48 can cause harm or discomfort to his hand 43 whereupon the marker 10 has the appearance generally shown in FIG. 3. The tabs 41 and 42 make possible the simple, effective, accurate and safe installation of the pavement marker 10.
If the installer desires, the tip regions 44 and 46 of his thumb and forefinger can extend beyond the tabs 41 and 42 and rest against adjacent surface portions of the upper surface 11, as shown in FIGS. 1 and 2. Also, other fingers of the same hand can rest against portions of the upper surface 11 or of a reflector 18 or 19 for stabilization reasons, as those skilled in the art will appreciate.
After installation, the tabs, such as tabs 41 and 42, are readily broken away from the upper rounded surface such as surface 11 by a relatively small applied bending force. The shape and configuration of the tabs is such that breakage at the level of the upper surface 11 occurs as compared to breakage along the length of a tab. Thus, tabs such as tabs 41 and 42 that are configured so as to be elongated in height and of uniform, thin construction so break at their base. Breakage force can be applied in any one of many ways, including finger pressure (perhaps by the installer after installation), hammer tapping, vehicle tire, such as the first tire after installation which rolls over the pavement marker 10, or the like. After tab breakaway, characteristically only a slight almost imperceptible imperfection remains upon the surface 11. This imperfection has no known adverse effect or consequence regarding usability, usage or even appearance of the resulting pavement marker.
As those skilled in the art will appreciate, a pavement marker, such as marker 11 or the like, can have any convenient or desired composition or structure. Any convenient, moldable material can be used. However, moldable materials such as plastic, metal or ceramic are convenient with plastic being presently preferred.
Various marker fabrication procedures can be used as those skilled in the art will appreciate. An advantage of this invention is that the known fabrication procedures generally can be used, if desired, with only slight mold preliminary changes. One fabrication procedure for use with plastic is to first mold the upper surfaces 11 and associated edge 12 with the regions 31-34 and 36-39 being included. Then, reflectors 18 and 19 are positioned behind windows provided in the finished molding, the window size being such that a small overlap is provided in the upper surface 11 about perimeter edge portions of each reflector 18 and 19. Thereafter, the interior cavity of the pavement marker 10 can be filled with a liquified epoxy resin or other plastic which thereafter thermosets or solidifies into a solid state while the marker structure is housed in a mold. The bottom face 13 of a marker is thus concurrently formed.
Another suitable and presently preferred fabrication procedure is fully described in my copending U.S. patent application filed on even date herewith, the disclosure and contents of which are fully incorporated hereinto by reference and which is identified by docket no. EMP2.
One presently preferred type of tab is illustrated in FIG. 6 by tab 42. Such tab is radially elongated in width relative to depth as an above explained preference. The central portion of such tab 42, however, is provided with a generally vertically extending cylindrically thickened portion 49 which, as those skilled in the art will appreciate, can be provided by leaving out a knock out pin in one portion of a mold assembly that is being used to form the marker 10. Preferably the radially interior, upwardly extending edge 51 of tab 42 is formed as to diagonally extend in a direction diverging from the axis 14 for reasons of facilitating easy mold release, as those skilled in the art will appreciate.
As is normal in the pavement marker art, a pavement marker of the invention need have no associated reflector at all. For example, it is common practice to locate one or a series of successive pavement markers each having no reflector between a spaced pair of reflectorized pavement markers along a roadway. To achieve such an unreflectorized pavement marker structure, a pavement marker can be structured as described above in relation to marker 10, but without any reflector at all. The result is a pavement marker embodiment 52 of this invention whose upper surface 53 is generally spherically convexly curved as shown in FIG. 7. The surface 53 is provided either with a pair of tabs 54 and 56 which can be similar in structure and position to tabs 41 and 42, or with a tab 50 alternatively.
Also, as those skilled in the art will appreciate, a pavement marker of the invention can have only a single reflector element which is viewable from one general approach direction only. Such a pavement marker embodiment 57 of this invention is shown in FIG. 8. Such a marker 57 is structured as described above in relation to marker 10, but incorporates only a single recessed reflector 58 which can correspond to either reflector 18 or 19. The result is the pavement marker 57 which has a convexly rounded top surface 59 except on the reflector 58 that is inset thereinto. The rounded surface 59 is provided with tabs 61 and 62 that are similar to tabs 41 and 42 and the tabs 54 and 56.
The pavement markers 10, 52 and 57 preferably consist of a molded plastic shell and core and are particularly well adopted for use as temporary raised pavement markers in road construction zones and the like.
Preferably, a pavement marker body is comprised of a molded plastic such as ABS (acrylonitrile/butadiene/styrene), polycarbonate, methylmethacrylate, or the like, and preferably a reflex reflector is comprised of a clear molded plastic such as methyl methacrylate or other acrylic resin. If a reflector is associated with a body the reflector as preferably mechanically sealed to the body around the reflector periphery by encapsulation between the marker body housing and core assembly to eliminate the entrance of moisture and dirt. The face of the reflex reflector is preferably flat and smooth. Preferably the face of the reflex refection is recessed into the marker body at least about 0.156 inch (3.97 mm) to protect it from direct contact with vehicle tires. The body is preferably white or yellow and the reflex reflector is either colorless or tinted yellow in color. The body is preferably compatible with all commercial pavement marker adhesives, including tar (bitumous) butyl-type, epoxy type, and the like. Both the marker body and the reflectors mounted thereon are preferably each comprised of, UV stabilized plastics to resist sun fade.
Since other and further embodiments and features will be apparent to those skilled in the art from these teachings of the present invention, no undue limitations are to be drawn therefrom.
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Pavement markers are provided that are equipped with installation tabs which permit marker storage vertically and which permit hand holding of the individual markers during installation. After a marker is installed, each tab is breakable adjacent to the marker upper surface in response to an applied small bending force. The tabs overcome the problem of installing pavement markers upon hot tar.
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RELATED APPLICATIONS
This application is a continuation-in-part of commonly assigned, U.S. patent application Ser. No. 08/922,812 filed Sep. 3, 1997 now abandoned, which is a continuation of Ser. No. 08/582,950, entitled “POSTAL OIL BOX” and filed Jan. 4, 1996 now abandoned, which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates generally to distribution and recovery of recyclable/reclaimable products and in particular to packaging of recyclable/reclaimable products for efficient distribution and recovery. Still more particularly, the present invention relates to efficiently recovering recyclable/reclaimable products by distribution of new or unspent product in packaging adapted for capture of used or spent product and subsequent conveyance by commercial package service to a recycling/reclamation center.
2. Description of the Related Art
A variety of consumable goods or products are amenable to recycling and/or reclamation through suitable processes. An example is motor oil of the type and grade typically utilized for passenger and light transport vehicles. The American Petroleum Institute reports that 1.4 billion gallons of used motor oil is generated in the United States each year. Of this amount, the Environmental Protection Agency (EPA) estimates that, annually, approximately 143 million gallons—the equivalent of 14 Exxon Valdez spills each year—ends up contaminating the environment. Other studies indicate that the amount of improperly managed used motor oil may be as high as 455 million gallons each year. One oil change, or about one gallon of used motor oil, can contaminate one million gallons of drinking water. The contaminants found in used motor oil include: hydrocarbons at approximately the level found in virgin oils, polyalphahydrocarbons at increased levels due to contamination and chemical reactions during use of the motor oil, and—perhaps most harmful—heavy metals.
Waste oil handlers lacking the desire or expertise to properly manage used motor oil are significant contributors to this problem. However much of the used motor oil contaminating the environment comes from small quantity generators such as individuals performing their own automotive maintenance (often referred to as do-it-yourself oil changers or “DIYers”), pouring the used motor oil around a fence or tree or into the nearest storm drain. Industry studies indicate that 60% of the passenger cars and light duty trucks in the United States are serviced by individual owners. Farmers and small business owners with vehicle fleets of ten or less substantially increase the amount of used motor oil which is improperly managed.
Used motor oil can be recycled almost indefinitely since it never wears out, it only gets dirty. Use of re-refined motor oil in government vehicles is presently being mandated or encouraged at both the state and federal levels. In addition to being re-refined, reclaimed may be used as burner fuels and in other applications.
A principal obstacle to encouraging recycling of used motor oils, particularly with individuals maintaining their own vehicles, is convenience in capturing the used motor oil in a container suitable for transportation and/or transmitting the used motor oil to an appropriate recycling facility. Participation by individuals is hampered by the inconvenience of capturing the used oil, pouring the used oil into a container for transportation, and transporting the used oil to the recycling center. Not knowing what to do with the captured used oil (or other product), or not willing to take the necessary steps, many individuals allow the used oil to drain directly onto the ground or into a storm drain.
Even if the consumable goods cannot be recycled or reclaimed, often the goods require special handling for proper disposal, such as medical waste and the like. In such situations, again, a principle obstacle to obtaining proper disposal of the expended goods is transportation to an appropriate disposal facility.
It would be desirable, therefore, to provide a method and system for efficient distribution and recovery of recyclable/reclaimable consumable goods or goods requiring special disposal. It would further be advantageous for the method and system to be adaptable to distribution and recovery of goods which, when expended, consititute hazardous waste.
SUMMARY OF THE INVENTION
New or unused consumable product is distributed with a package capable of capturing the used or spent product for transmission to a recycling or disposal facility. The package is preaddressed for delivery to an appropriate reclamation center or disposal facility, with prepaid delivery charges for a commercial package service. At the reclamation center or disposal facility, the used or spent product is separated from the package for recycling and reusable portions of the package are again packaged with new or unused product, with any waste materials being properly handled. In the exemplary embodiment of motor oil, the package includes a drain pan jug for capturing the used motor oil and a shell for transmitting the drain pan jug and its contents to a reclamation facility. The shell may be reused until no longer serviceable, at which time it may be recycled. The drain pan jug, after use, may be shredded and utilized as fuel. Waste materials, such as a used oil filter, or medical waste in an alternative embodiment, are properly disposed of by a competent waste handler.
BRIEF DESCRIPTION OF THE DRAWINGS
The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings, wherein:
FIG. 1 depicts a diagram of a system for distribution and recovery of recyclable or reclaimable goods in accordance with a preferred embodiment of the present invention;
FIG. 2 is an exploded, perspective view of a package suitable for motor oil distribution and recovery in accordance with a preferred embodiment of the present invention;
FIGS. 3A-3C depict various views of the package for motor oil distribution and recovery in accordance with a preferred embodiment of the present invention; and
FIG. 4 is an illustration of a container for distribution of new or unused product in accordance with a preferred embodiment of the present invention.
DETAILED DESCRIPTION
With reference now to the figures, and in particular with reference to FIG. 1, a diagram of a system for distribution and recovery of recyclable or reclaimable goods in accordance with a preferred embodiment of the present invention is depicted. The exemplary embodiment depicted is for distribution and recovery of motor oil. Distribution and recovery system 100 begins with new or unused (i.e., recycled or reclaimed) product 102 in a condition suitable for consumption or for employment in its intended purpose. New or unused product 102 is received either from a production facility 104 , such as a manufacturing plant or refinery, or from recycle facility 106 in the form of recycled product. Production facility 104 and recycle facility 106 may be either the same or different enterprises. In the exemplary embodiment, production facility 104 may be a refinery producing motor oil in accordance with the known art, while recycle facility 106 may be a used motor oil recycling and/or reclamation center employing processes for recovery of usable motor oil from spent motor oil known in the industry.
New or unused product 102 is then packaged in a packaging facility 108 . Again, packaging facility 108 may be separate from or a part of the same enterprise as production facility 104 and/or recycle facility 106 . Packaging facility 108 packages the product in distribution packaging, which is provide in whole or in part from packaging manufacturing facility 110 or at least in part by packaging/product reclamation facility 112 and/or packaging regeneration facility 114 .
One feature of the present invention is that the distribution packaging employed to distribute new or unused product 102 is also employed to capture and recover the used or spent product. The entirety or merely a portion of the distribution packaging may therefore be utilized to transmit used or spent product to a recycling or reclamation facility. Suitable distribution and recovery packaging for the exemplary embodiment of motor oil is described in further detail below.
The packaged product is next transmitted through conventional distribution channels 116 (e.g., wholesale, retail, etc.) to the user 118 . User 118 utilizes the new or unused product 102 and captures the used or spent product with at least a portion of the distribution packaging. User 118 then transmits the recovered product, together with and contained within the portion of the distribution packaging utilized to recover the spent product, to a reclamation facility 122 through recovery channels 120 .
A second aspect of the present invention is that the recovery channels 122 are preferably commercial package services, such as the United States Postal Service, Federal Express, United Parcel Service, and the like. The portion of the distribution package which is designed for recovery of used or spent product may be pre-addressed for delivery to reclamation facility 122 . Delivery charges for transmission of the recovered product to reclamation facility 122 may also be prepaid, as with prepaid postage and the like. In this manner, recovery of the used or spent product for recycling or reclamation is greatly facilitated.
Within product/packaging reclamation facility 122 , the used or spent product is separated from the recovery packaging and transmitted to recycling facility 106 . Reusable and/or recyclable packaging is returned to packaging facility 108 , either directly if the packaging is reusable without significant restoration or through regeneration facility 114 if the packaging requires significant recycling. In the exemplary embodiment, part of the recovery packaging may be directly reused while another part is subject to regeneration as described in further detail below. Additionally, those portions of the contaminated or spent packaging which can not be either recycled or reused may be processed for use as fuel at fuel generation facility 124 or properly handled at disposal facility 126 in accordance with all federal, state and local regulations to insure protection of human health and the environment.
Referring to FIG. 2, an exploded, perspective view of a package suitable for motor oil distribution and recovery in accordance with a preferred embodiment of the present invention is illustrated. Package 200 may be employed in a distribution and recovery system of the type depicted in FIG. 1 . Illustrated in FIG. 2 are the packaging components which may be utilized for both distribution and recovery.
Package 200 includes upper and lower shells 202 and 204 , respectively, and a drain pan jug 206 . Upper and lower shells 202 and 204 are constructed of high density polyethelene (HDPE) preferably having wall thicknesses of approximately 0.12 inches. The composition and construction of upper and lower shells 202 and 204 are essentially the same as that of an ordinary plastic tackle box or tool case, and may be injection molded.
Drain pan jug 206 is also formed of HDPE, but has a lighter construction essentially the same as that of an ordinary plastic milk jug, and may thus be blow-molded, but of a type withstanding the properties of the spent material, such as the heat of drained used motor oil. Drain pan jug 206 fits within lower shell 204 , serves to capture used motor oil as it is drained from a vehicle, and holds captured used or spent motor oil during transmission to a reclamation facility. The details of the construction of package 200 are described further below.
With reference now to FIGS. 3A through 3C, various views of the package for motor oil distribution and recovery in accordance with a preferred embodiment of the present invention are depicted. FIG. 3A depicts package 200 in an assembled state, with upper shell 202 affixed to lower shell 204 to form a liquid-impermeable enclosure therein. Upper and lower shells 202 and 204 both have battered or slanted sides as depicted, to facilitate nested stacking of empty shells as described below. Upper shell 202 includes a stacking ledge 302 in the upper surface 304 defining a recess 306 for receiving stacking rails 308 on the bottom surface of lower shell 204 . Thus package 200 , when assembled, may be reliably stacked upon a similar assembled package.
Package 200 , when assembled, is preferably approximately 10 inches high and 12 inches in length and width, dimensions which are compatible with existing shipping requirements and shelving requirements. See, for example, Publication 52 and Domestic Mail Services (DMM Issue 42, Mar. 15, 1992) sections 120-124 by the United States Postal Service, and the applicable sections of the United States Code and Code of Federal Regulations, all of which are incorporated herein by reference.
Upper and lower shells 202 and 204 both include, along each major edge of the rims at which they are joined, a lip 310 oppositely oriented with respect to the rim of the respective upper or lower shell 202 or 204 . In the example shown, lip 310 is a protrusion from the rim of the respective upper or lower shell 202 or 204 having a T- or L-shaped cross-section. On at least one of the upper and lower shells 202 and 204 , lip 310 extends for only a portion of the edge length, providing a catch for sliding latch 312 .
Sliding latch 312 , situated on one of the upper or lower shells 202 or 204 , may be slid between open and locked positions to additionally secure upper and lower shells 202 and 204 forming the enclosure within package 200 . Latch 312 has a generally C-shaped cross-section to engage a “guide” lip 310 on either shell 202 or 204 and an opening (not shown) along one edge so that latch 312 , when upper and lower shell 202 and 204 are fitted together, receives the “catch” lip 310 on the opposite shell 202 or 204 when in the open position and engages the “catch” lip 310 on the opposite shell 202 or 204 when in the locked position.
Lower shell 204 , on at least two opposite sides of package 200 , also includes recessed handles 314 beneath the rim at which upper and lower shells 202 and 204 are fitted together and behind lip 312 on lower shell 204 . Recessed handle 314 may be formed by an indented portion of the sidewall of lower shell 204 leading to a small (e.g., 0.75 inch by 3 inch) area oriented substantially perpendicularly to the sidewalls of lower shell 204 .
FIG. 3B depicts a cut-away view of the assembled package 200 , including drain pan jug 206 as well as upper and lower shells 202 and 204 . Drain pan jug 206 is of liquid-impermeable with the exception of opening 316 in the upper surface 320 . Opening 316 includes sidewalls 318 extending into the interior of drain pan jug 206 . The perimeter of the upper surface 320 of drain pan jug 206 is surrounding by a lip 322 , and the upper surface 320 is sloped in all directions from the perimeter to opening 316 . Drain pan jug 206 does not significantly protrude above the height of lower shell 204 when nested therein. The combined height of lower shell 204 and drain pan jug 206 when drain pan jug 206 is nested within lower shell 204 is preferably small enough to permit insertion under a typical vehicle (e.g., less than about 6-8 inches high). Drain pan jug 206 may therefore be employed to capture used motor oil as it is drained from a vehicle, with the sloped upper surface 320 directing captured motor oil to opening 316 and thence to the interior of drain pan jug 206 . Lower shell 204 includes interior support ribs 324 for supporting drain pan jug 206 .
An integral plug 326 protruding from an interior upper surface on upper shell 202 fits into and seals opening 316 on drain pan jug 206 when upper and lower shells 202 and 204 are fitted together with drain pan jug 206 contained therein. One or more O-rings 328 around plug 326 or the inner perimeter of opening 316 may provide the necessary sealing capability. Plug 326 , and opening 316 within the upper surface 320 of drain pan jug 206 , are preferably offset from the center of the respective surface (the interior upper surface of upper shell 202 or upper surface 320 of drain pan jug 206 ) to provide an obvious indication of the orientation in which upper shell 202 , lower shell 204 , and drain pan jug 206 are proper fitted together.
FIG. 3C depicts a cross-sectional view of the toungue-and-groove latching mechanism providing retention of upper shell 202 to lower shell 204 . An outer surface of the rim of lower shell 204 slopes to a curved end of the rim. The rim of upper shell 202 is forked, with a catch on the interior of the outer fork situated to form a neck through which the ball-shaped end of the lower shell rim cannot pass. However, a device inserted between the upper and lower shell rims may force the fork branches on the upper shell rim apart sufficiently to allow the ball-shaped end of the lower shell rim to pass. This tongue-and-groove type mechanism provide both mechanical retention of the upper and lower shells 202 and 204 and sealing of the enclosure therein. Additional reinforcement of the mechanical retention is provided by the sliding latches described above. In an alternative embodiment, O-ring seals may be utilized in lieu of the tongue-and-groove construction.
Referring to FIG. 4, a container for distribution of new or unused product in accordance with a preferred embodiment of the present invention is illustrated. Bag 400 is employed to distribute new or unused product. Bag 400 is of a material similar to intravenous (“IV”) solution bags employed by medical professionals.
Referring now to FIGS. 1-2, 3 A- 3 C and 4 together, package 200 may be employed to distribute new or unused motor oil and to recover used or spent motor oil with distribution and recovery system 100 . New or unused motor oil is placed in bag 400 and packaged together with package 200 for distribution to the consumer. The consumer 118 utilizes drain pan jug 206 to capture the used or spent motor oil, then places drain pan jug 206 with the captured motor oil in lower shell 204 . New or unused motor oil is then transferred to the vehicle from bag 400 , which is placed on top of drain pan jug 206 together with the used oil filter. Upper shell 202 is then fitted to lower shell 204 to plug the opening in drain pan jug 206 and to encapsulate drain pan jug 200 , bag 400 from which the new or unused motor oil was dispensed, the used oil filter, and any other oil contaminated materials, such as paper towels, for proper management. Upper shell 202 is prelabeled with the delivery address of an appropriate reclamation center and includes prepaid postage or other indicia of payment for the delivery services. Package 200 and its contents are then left by the consumer 118 in a suitable location for pickup by the commercial package service.
The commercial package service conveys package 200 and its contents to reclamation facility 122 . At reclamation facility 122 , upper and lower shell 202 and 204 are separated and the contents removed. The used oil filter and the empty bag 400 are properly handled. Drain pan jug 206 and its contents are placed in a commercial shredder, which shreds drain pan jug 206 and separates the used motor oil from the pieces of drain pan jud 206 . The used motor oil is transmitted to product recycling facility 106 for recycling. The shredded remains of drain pan jug 206 is transmitted for use as fuel, providing up to three times the energy of an equivalent mass of coal.
Upper and lower shell 202 and 204 are, if in suitable condition, returned to packaging facility 108 for reuse. If worn or otherwise unusable, however, upper and lower shell 202 and 204 are first recycled by existing methods for use as feedstock for injection molding processes, including manufacture of new upper and lower shells.
The present invention permits reusable product to be efficiently recovered by transmission of replacement product with a package suitable for capture of used product and transmission to an appropriate reclamation facility via common commerical package delivery services. This eliminates a principle obstacle to recovery of spent product which has resulted in improper handling: the effort required to transport the used product to an appropriate recycling or disposal facility. The principle of the invention may be extended to hazardous waste, such as medical waste.
The description of the preferred embodiment of the present invention has been presented for purposes of illustration and description, but is not intended to be exhaustive or limit the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiment was chosen and described in order to best explain the principles of the invention and the practical application to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated.
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New or unused consumable product is distributed with a package capable of capturing the used or spent product for transmission to a recycling or disposal facility. The package is preaddressed for delivery to an appropriate reclamation center or disposal facility, with prepaid delivery charges for a commercial package service. At the reclamation center or disposal facility, the used or spent product is separated from the package for recycling and reusable portions of the package are again packaged with new or unused product, with any waste materials being properly handled. In the exemplary embodiment of motor oil, the package includes a drain pan jug for capturing the used motor oil and a shell for transmitting the drain pan jug and its contents to a reclamation facility. The shell may be reused until no longer serviceable, at which time it may be recycled. The drain pan jug, after use, may be shredded and utilized as fuel. Waste materials, such as a used oil filter, or medical waste in an alternative embodiment, are properly disposed of by a competent waste handler.
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TECHNICAL FIELD
[0001] The present invention relates to an electronic device, and relates, for example, to an electronic device that waterproofs an electroacoustic transducer provided inside a casing.
BACKGROUND ART
[0002] Hitherto, a telephone provided with a waterproof film for waterproofing an acoustic part has been known (see Patent Literature 1, for example).
[0003] FIG. 1 is an exploded perspective view of principal parts of conventional electronic device 1 such as a telephone. Conventional electronic device 1 mainly comprises casing 10 , cushion member 11 , film member 12 , cushion member 13 , and electroacoustic transducer 14 .
[0004] Casing 10 has plurality of sound holes 50 , which are through-holes. Sound holes 50 output speech generated from electroacoustic transducer 14 to the exterior of casing 10 .
[0005] Cushion member 11 is provided between casing 10 and film member 12 , and provides a seal between casing 10 and film member 12 .
[0006] Film member 12 is circular viewed from above, and is provided between cushion member 11 and cushion member 13 . Film member 12 prevents water or other liquids from penetrating into the interior of casing 10 from sound holes 50 .
[0007] Cushion member 13 is provided between film member 12 and electroacoustic transducer 14 , and provides a seal between film member 12 and electroacoustic transducer 14 .
[0008] Electroacoustic transducer 14 is a speaker, for example.
[0009] In recent years, as portable terminals such as mobile phones have become smaller in size, rectangular electroacoustic transducers have been used in order to achieve an efficient parts layout inside the casing.
CITATION LIST
Patent Literature
[PTL 1]
[0010] Japanese Patent Application Laid-Open No. HEI8-79865
SUMMARY OF INVENTION
Technical Problem
[0011] However, if a film member is made rectangular in line with the shape of a rectangular electroacoustic transducer, distances from the center of the surface of the film member to the sides become unequal. Consequently, when the film member vibrates due to speech generated from the electroacoustic transducer, there is a problem of frequency components of various different frequencies being produced, and speech output from the sound holes in the casing being distorted.
[0012] On the other hand, if a round film member is used in the conventional way, speech distortion does not occur since distances from the center of the surface of the film member to peripheral edges become equal. However, if a round film member is still used even though the electroacoustic transducer has been made rectangular, there is a problem of sound leakage occurring due to the creation of a gap between the film member and the electroacoustic transducer.
[0013] It is an object of the present invention to provide an electronic device that can ensure waterproofing and dustproofing, and can prevent both speech distortion and sound leakage at the same time, when a rectangular electroacoustic transducer is used.
Solution to Problem
[0014] An electronic device of the present invention employs a configuration having a casing, first sound holes provided in the casing, a substantially rectangular electroacoustic transducer provided inside the casing, a substantially circular film member provided between the first sound holes and the electroacoustic transducer, a planar member provided between the film member and the electroacoustic transducer, and second sound holes provided in the planar member.
ADVANTAGEOUS EFFECTS OF INVENTION
[0015] The present invention can ensure waterproofing and dustproofing, and can prevent both speech distortion and sound leakage at the same time, when a rectangular electroacoustic transducer is used.
BRIEF DESCRIPTION OF DRAWINGS
[0016] FIG. 1 is an exploded perspective view of principal parts of a conventional electronic device;
[0017] FIG. 2 is an exploded perspective view of principal parts of an electronic device according to an embodiment of the present invention;
[0018] FIG. 3 is a cross-sectional view of an electronic device according to an embodiment of the present invention;
[0019] FIG. 4 is a plan view showing the mutual positional relationship of a film member, electroacoustic transducer, and sound holes according to an embodiment of the present invention;
[0020] FIG. 5 is a plan view showing the mutual positional relationship of a film member, electroacoustic transducer, and sound holes according to an embodiment of the present invention; and
[0021] FIG. 6 is an exploded perspective view of an electronic device according to an embodiment of the present invention.
DESCRIPTION OF EMBODIMENTS
[0022] Now, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.
Embodiment
[0023] FIG. 2 is an exploded perspective view of principal parts of electronic device 100 according to an embodiment of the present invention.
[0024] Electronic device 100 mainly comprises first casing 101 , cushion member 102 , film member 103 , cushion member 104 , planar member 105 , cushion member 106 , and electroacoustic transducer 107 . Electronic device 100 is, for example, a communication terminal apparatus such as a mobile phone, or a portable TV. Cushion member 102 , film member 103 , cushion member 104 , planar member 105 , cushion member 106 , and electroacoustic transducer 107 are housed in an interior space formed by another casing described later herein that is separate from first casing 101 , and first casing 101 . However, in FIG. 2 , only a part of first casing 101 is shown, and another casing is not shown.
[0025] First casing 101 has plurality of sound holes 110 , which are through-holes.
[0026] Cushion member 102 is provided between first casing 101 and film member 103 . Cushion member 102 has an adhesive section of double-sided adhesive tape or the like on its upper surface and lower surface, and creates a seal between first casing 101 and film member 103 through the adhesion of the respective adhesive sections to first casing 101 and film member 103 . Cushion member 102 is circular viewed from above, and has circular through-hole 112 in its center.
[0027] Film member 103 is thin film that is approximately circular viewed from above, and is provided between cushion member 102 and cushion member 104 . Film member 103 is formed from a material that allows speech generated from electroacoustic transducer 107 to pass through without being attenuated, and is, for example, a microporous membrane of PTFE or the like. Film member 103 prevents water or other liquids, or dust, that penetrates from sound holes 110 , from further penetrating to electroacoustic transducer 107 . That is to say, film member 103 functions as a waterproof film or dustproof film. The term “approximately circular” here includes a polygonal shape in which distances from the center to the periphery are approximately uniform, including, essentially, various shapes that are approximately circular and that do not give rise to various frequency components that cause speech distortion when they vibrate due to speech.
[0028] Cushion member 104 is provided between film member 103 and planar member 105 . Cushion member 104 has an adhesive section of double-sided adhesive tape or the like on its upper surface and lower surface, and creates a seal between film member 103 and planar member 105 through the adhesion of the respective adhesive sections to film member 103 and planar member 105 . Cushion member 104 is circular viewed from above, and has circular through-hole 114 in its center.
[0029] Planar member 105 is of thin planar shape, and is provided between cushion member 104 and cushion member 106 . Planar member 105 has two sound holes 111 , which are through-holes. The number of sound holes 111 is not limited to two, but may be three or more, or one.
[0030] Cushion member 106 is provided between planar member 105 and electroacoustic transducer 107 . Cushion member 106 has an adhesive section of double-sided adhesive tape or the like on its upper surface and lower surface, and creates a seal between planar member 105 and electroacoustic transducer 107 through the adhesion of the respective adhesive sections to planar member 105 and electroacoustic transducer 107 . Cushion member 106 is rectangular viewed from above, and has rectangular through-hole 115 in its center.
[0031] Electroacoustic transducer 107 is approximately rectangular viewed from above. Electroacoustic transducer 107 is a speaker, for example. In addition to a rectangular shape, the term “approximately rectangular” here includes an octagonal shape with four corners cut obliquely, for example, including, essentially, various shapes that are approximately rectangular and that enable an efficient parts layout to be achieved inside the casing.
[0032] FIG. 3 is a cross-sectional view of electronic device 100 . As shown in FIG. 3 , inside first casing 101 of electronic device 100 , electroacoustic transducer 107 , cushion member 106 , planar member 105 , cushion member 104 , film member 103 , and cushion member 102 are stacked in that order. Sound holes 110 are provided in first casing 101 so as to be located within range L in which film member 103 and electroacoustic transducer 107 overlap in a plan view (looking downward from above in FIG. 3 ). Similarly, sound holes 111 are provided in planar member 105 so as to be located within range L in which film member 103 and electroacoustic transducer 107 overlap in a plan view. Also, sound holes 110 are provided at positions in which they mutually overlap with sound holes 111 in a plan view. Film member 103 is located between sound holes 110 and sound holes 111 . However, since film member 103 is formed from a material that allows speech to pass through without being attenuated, speech that has passed through sound holes 111 can be guided to sound holes 110 without being attenuated.
[0033] FIG. 4 is a plan view showing the mutual positional relationship of film member 103 , electroacoustic transducer 107 , and sound holes 110 . From FIG. 4 , it can be seen that sound holes 110 are located at positions in which they overlap both film member 103 and electroacoustic transducer 107 in a plan view.
[0034] FIG. 5 is a plan view showing the mutual positional relationship of film member 103 , electroacoustic transducer 107 , and sound holes 111 . From FIG. 5 , it can be seen that sound holes 111 are located at positions in which they overlap both film member 103 and electroacoustic transducer 107 in a plan view.
[0035] Sound holes 110 and sound holes 111 are formed so that the total area of sound holes 111 in the surface of planar member 105 is greater than the total area of sound holes 110 in the surface of first casing 101 . By this means, speech that has passed through sound holes 111 can pass through sound holes 110 without being attenuated. Here, the total area of sound holes 110 can be found by multiplying the area of one sound hole 110 by the total number of sound holes 110 . That is to say, in the case shown in FIG. 4 , the total area of sound holes 110 can be found by means of equation 1.
[0000] Total area of sound holes 110 S 1=(( r 1÷2)2×π)×10 (Equation 1)
[0036] where r 1 is the diameter of sound holes 110 .
[0037] Also, the total area of sound holes 111 can be found by multiplying the area of one sound hole 111 by the total number of sound holes 111 . That is to say, in the case shown in FIG. 5 , the total area of sound holes 111 can be found by means of equation 2.
[0000] Total area of sound holes 111 S 2=(( r 2÷2)2×π)×2 (Equation 2)
[0038] where r 2 is the diameter of sound holes 111 .
[0039] By this means, sound holes 110 and sound holes 111 are formed so that S 1 ≦S 2 . As long as this condition is satisfied, the shape and number of sound holes 110 and sound holes 111 are not limited to those in this embodiment.
[0040] FIG. 6 is an exploded perspective view of electronic device 100 . Electronic device 100 comprises first casing 101 , intermediate casing 501 , and second casing 502 .
[0041] First casing 101 has a U-shaped cross-section and has sound holes 110 . Cushion member 102 , film member 103 , and cushion member 104 are housed in an interior space formed by first casing 101 and intermediate casing 501 .
[0042] Intermediate casing 501 has, integrally, recessed planar member 105 having sound holes 111 . First casing 101 is attached to intermediate casing 501 so as to cover planar member 105 . Cushion member 102 and film member 103 are placed on recessed planar member 105 , and are covered by first casing 101 . Intermediate casing 501 is attached to second casing 502 so as to cover the upper surface of second casing 502 .
[0043] Second casing 502 has parts layout section 503 on which an electrical circuit pattern (not shown) is formed. Electroacoustic transducer 107 , to which cushion member 106 is attached, is attached to parts layout section 503 and electrically connected to the electrical circuit pattern on parts layout section 503 .
[0044] The method of assembling electronic device 100 will now be described using FIG. 2 and FIG. 6 .
[0045] First, cushion member 106 is attached to the outer part of the upper surface of electroacoustic transducer 107 , and electroacoustic transducer 107 is placed on parts layout section 503 of second casing 502 so as to be electrically connected to the electrical circuit pattern on parts layout section 503 .
[0046] Next, film member 103 is attached to planar member 105 by means of cushion member 104 at a position to seal off sound holes 111 .
[0047] Next, first casing 101 is attached to intermediate casing 501 so as to cover planar member 105 of intermediate casing 501 . By this means, film member 103 is attached to first casing 101 , by means of cushion member 102 , in a position to seal off sound holes 110 .
[0048] Next, intermediate casing 501 is attached to second casing 502 . By this means, cushion member 106 is attached to planar member 105 , and electronic device 100 is completed.
[0049] This concludes a description of the method of assembling electronic device 100 .
[0050] In electronic device 100 of this kind, speech output from electroacoustic transducer 107 reaches film member 103 after passing through through-hole 115 of cushion member 106 , sound holes 111 , and through-hole 114 of cushion member 104 , in that order. Then speech that has reached film member 103 passes through film member 103 . At this time, film member 103 vibrates due to the speech passing through. Since film member 103 is circular, speech that passes through film member 103 is not distorted.
[0051] Next, speech that has passed through film member 103 passes through through-hole 112 of cushion member 102 and sound holes 110 , and is output to the exterior of electronic device 100 .
[0052] Water or other liquids, or dust, that penetrates into the interior of electronic device 100 from sound holes 110 passes through through-hole 112 of cushion member 102 . However, water or other liquids, or dust, cannot penetrate further into the interior of electronic device 100 due to film member 103 .
[0053] Thus, according to this embodiment, by providing a planar member provided with sound holes between a casing and an electroacoustic transducer, and also providing a circular film member between the casing and the planar member, waterproofing and dustproofing can be ensured, and both speech distortion and sound leakage can be prevented at the same time, when a rectangular electroacoustic transducer is used. Also, by making the total area of sound holes provided in the planar member in the surface of the planar member greater than the total area of sound holes provided in a first casing in the surface of the first casing, speech generated from the electroacoustic transducer can be output to the exterior without being attenuated. Furthermore, according to this embodiment, by providing a plurality of sound holes in the planar member, a decrease in the strength of the planar member associated with sound hole formation can be reduced.
[0054] In this embodiment, a case has been described in which electroacoustic transducer 107 is a speaker. However, the present invention is not limited to this, and can be applied to any electroacoustic transducer, such as a microphone, receiver, or the like, as well as a speaker.
[0055] In the present invention, a planar member has been assumed to be integral with an intermediate casing. However, the present invention is not limited to this, and a planar member may also be a separate entity from an intermediate casing.
[0056] In this embodiment, a seal is provided between first casing 101 and film member 103 , and film member 103 and planar member 105 , by means of cushion member 102 and cushion member 104 respectively. However, the present invention is not limited to this, and provision may also be made for adhesive sections enabling adhesion to first casing 101 and planar member 105 to be provided on film member 103 , and for cushion member 102 and cushion member 104 to be eliminated.
[0057] The disclosure of Japanese Patent Application No. 2008-139792, filed on May 28, 2008, including the specification, drawings and abstract, is incorporated herein by reference in its entirety.
INDUSTRIAL APPLICABILITY
[0058] The present invention is suitable for use in an electronic device such as a mobile phone, portable audio player, digital camera, digital video camera, notebook PC, electronic dictionary, portable game machine, portable TV, and so forth.
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Disclosed is an electronic apparatus which can ensure waterproofness or dustproofness when a rectangular electroacoustic transducer is employed, and can prevent both distortion of voice and leakage of sound at the same time. A first casing ( 101 ) of the electronic apparatus has sound holes ( 110 ). A film member ( 103 ) is substantially circular and provided between the sound holes ( 110 ) and an electroacoustic transducer ( 107 ). A planar member ( 105 ) is provided between the film member ( 103 ) and the electroacoustic transducer ( 107 ) and has second sound holes ( 111 ). The electroacoustic transducer ( 107 ) is substantially rectangular and generates voice.
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FIELD OF INVENTION
[0001] This invention relates generally to Internet marketing and specifically to unique visitor identification problem, which is the principle uncertainty in assessing the size of the market (i.e. core audience size) reachable via Internet advertisement.
BACKGROUND
[0002] When we advertise we want to know the size of the market we are advertising to. We want to know how many potential customers our advertisement will reach and we use this number to estimate sales and control the cost of advertising. Since the price of advertisement charged by content providers (such as newspapers, TV networks, radio stations, Internet sites, etc.) usually depends on the reach knowing the reachable audience size is extremely important for determining the cost effectiveness of advertisement and estimating return on investment—ROI—as a ratio of the projected sales revenue to the cost of advertising.
[0003] While for the traditional-media advertising (i.e. TV, radio, print, etc.) methods for estimating the reach are well developed, the same methods cannot be applied for the new-media advertising (such as advertising on Internet). The traditional-media advertising uses the number of subscribers as a fair approximation of the reach; radio advertising relies on manual call-out marketing to estimate the audience size. Internet advertisement in general is not delivered to subscribers while expensive and tedious call-out marketing is almost universally replaced with computerized unique visitor estimation techniques based on analysis of site access logs.
[0004] The two most popular unique visitor estimation techniques for Internet advertisement include the count of unique network addresses (such as IP addresses) mined from site access logs [1, 2, 3] or the count of unique “cookies” [4] also mined from site access logs [5].
[0005] The problem with the first method is that network addresses change over time; therefore the same visitor may be assigned a different network address upon a return visit and thus be misidentified as a new visitor. Furthermore network addresses are also reused; therefore two distinct visitors may share the same network address on subsequent visits and thus be misidentified as one. No formal research in the area has been conducted until now [6] and the obtained results sharply contradict currently accepted notion in the field that the ratio of unique network addresses to unique visitors is constant and is on the order of 1. The research conducted by the author [6] has revealed that the ratio of unique network addresses to unique visitors is not constant and grows linearly with sampling time and with visitation frequency. In other words if an Internet site reports 1,000,000 unique visitors per month basing this number on the count of unique network addresses the actual number of unique visitors may be 30 times less (e.g. ˜30,000) if majority of users—the core audience—visit the site twice daily.
[0006] The potential inaccuracy of the network address counts as a measure of unique visitors has been realized before and a new method of unique visitor identification based on “cookies” has been developed [5]. “Cookie” is a persistent and unique token of information that is submitted (typically by Web Browser) to Internet site in order to identify a user on a return visit. When a new user comes in a new unique cookie value is generated to identify the user on a return visit. Currently cookie-tracking methods are considered the most reliable and amount to industry standard in unique visitor identification. Google Analytics, Yahoo, SpyLog and other online content rating providers rely on this method for calculating the unique visitor numbers. Potential problems that negatively impact the accuracy of the cookie-tracking method include cookie clearing by users (both periodic and sporadic, including deletion of cookies by software such as Antivirus or disk cleaning programs) and explosive proliferation of Internet access points and devices such as smart phones, PDAs, pocket PCs, game consoles, notebook PCs, etc. Since cookies are specific to each device, a person that uses 10 such devices will appear as 10 unique visitors to a cookie-tracking system. Currently the impact of cookie clearing and Internet access device proliferation is vastly neglected and unique cookie counts are nevertheless used as a direct measure of unique visitors. The research conducted by the author [6] revealed that cookies are subject to the same “explosion” mechanism as network addresses: the ratio of unique cookie counts to unique visitors is not constant and grows linearly with sampling time and the growth factor increases with the increase of visitation frequency. The author's findings on the cookie clearing impact (which is only one of contributing factors of inaccuracy) corroborate similar data recently reported by comScore [7].
[0007] Thus cookies are about just as inaccurate in estimating unique visitors as unique network addresses. This is the new and unrealized fact in the industry that has a direct impact on Internet advertising as currently reported unique visitor/core audience size numbers tend to overestimate the true audience size by a large factor (7-30, depending on the visitation frequency and the sampling period). Also, cookies are not supported by all Internet access hardware/software devices and generally cannot be used with Internet audio/video streams thus further limiting the area of cookie-tracking applicability.
[0008] To remedy the problem the author has invented a new, novel and highly unobvious method for estimating unique visitors discussed below.
OBJECTS AND ADVANTAGES
[0009] The key advantage of the present invention is that the invented method of unique visitors estimation is markedly more accurate than the existing unique-network-address-counting and unique-cookie-tracking methods. Another advantage of this invention is simplicity and ease of implementation: the invented method can be implemented as an add-on to an existing cookie or network address-based visitor identification system.
SUMMARY OF INVENTION
[0010] I hereby disclose a method for unique visitor identification using the data extracted from the Internet site access logs.
[0011] The method operates under the assumption that the meaningful traffic is periodic, i.e. that the site has a core audience that visits the site regularly. It is our task to estimate this core audience size, which is the unique visitors number. While there are going to be additional unique visitors outside of the core audience (i.e. visitors that stumbled upon the site randomly) I argue that the number of these newcomers is likely to be small in comparison to the core audience size when the site is well established (as opposed to newly created). Furthermore, some of these newcomers may convert to regulars and contribute to the core audience size increase thus supporting the assumption that at any given time the core audience is likely to be much larger than the number of newcomers for an established site.
[0012] Preferably, the method for estimating unique visitors should receive input from an existing cookie tracking/user access logging system, which serves as a basis for calculating the number of unique visitors according to the following formula:
[0000] I≡I 0 U=U ( C 0 +X N ) (1)
[0013] where I is the count of unique cookies, U is the number of unique visitors, C 0 is a constant (C 0 =1 when using unique cookie counts), X is the inflation factor, N is the visit number, an integer related to the sampling period t as:
[0000] N=t T 1 −1 (2)
[0014] where T 1 is the visitation frequency.
[0015] In other words N numbers return visits starting from zero.
[0016] For sites with multiple visitation frequencies a sum for all significant visitation frequencies T k −1 should be used:
[0000] I=Σq k U ( C k +X k N k ) (3)
[0017] where q k is the fraction of the core audience with the visitation period T k , 0<q k <1, N k =t T k −1 −1, and C k =1.
[0018] Alternatively, the method can be used to complement an existing access logging system without cookie tracking mechanism and thus rely only on unique network address counts to obtain the unique visitor estimates using the formulas (1) and (3). In this alternative scenario the variable I in expressions (1) and (3) refers to the count of unique network addresses (e.g. IP addresses); C 0 ≦1, C k ≦1 when using unique IP address counts (for most practical purposes C 0 ≈C k ≈1).
[0019] In order to complete the calculation of the unique visitors the inflation factor X must be determined empirically by mining site access logs. The visitation frequency can be determined in many ways, including but not limited to the following:
Automatically, e.g. via online surveying of visitors and/or content subscribers Manually, e.g. via off-line surveying of known site visitors or target demographic that is likely to contain the site visitors; online surveying current site visitors (e.g. via chat or other methods of online communication); etc. From mining site access logs and extracting the visitation frequency of unambiguously identified returning visitors (such as content subscribers, registered users identified by their logins, pins; repeat visitors identified by cookies, etc.) From mining repository of multitude of site access logs (e.g. generated by search engines, hosting providers, user tracking providers, etc.) and establishing averages for sites based on content category, target demographics, traffic volume, traffic patterns, etc.
[0024] For maximum accuracy the inflation factor X and the visitation frequency can be monitored continuously and adjusted periodically.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] FIG. 1 illustrates the unique network address count increase with time.
[0026] FIG. 2 illustrates the unique cookie count increase with time.
[0027] FIG. 3 depicts formulas used for computation of the unique visitor counts.
[0028] FIG. 4 illustrates the general process for determining the unique visitor counts according to the invented method.
[0029] FIG. 5 illustrates the process of determination of inflation factors X k , visitation frequencies T k −1 , and visitor fractions q k .
[0030] FIG. 6 illustrates the preferred system for determining the unique visitor counts according to the invention
[0031] FIG. 6 illustrates an alternative system for determining the unique visitor counts according to the invention
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0032] Contrary to the currently accepted notion both unique network address and unique cookie counts taken at face value provide a poor measure of unique visitors. The research conducted by the author based on the analysis of web site traffic logs [6] revealed persistent overestimation of unique visitors that grows linearly with time when unique network addressed (e.g. IP addresses) are used as a measure of unique visitors— FIG. 1 .
[0033] The count of unique cookies—which is considered to be a more reliable measure than the count of unique addresses and a de-facto industry standard for determining the unique visitors—also grows linearly with sampling time— FIG. 2 .
[0034] From this analysis the formulas for calculating the unique visitors U from the unique network address/unique cookie counts were derived— FIG. 3 .
[0035] These new, surprising and highly unobvious findings were analyzed by the author and a novel method for estimating the unique visitors was developed, which is illustrated on FIG. 4 . For an arbitrary sampling period t the method works as follows:
1. Visitor unique-identifying cookie value (and/or the network address) is recorded into a site access log for each user visit during the sampling interval t producing a combined count—I—of unique cookie values (and/or unique network addresses). 2. The average visitation frequency (or multiple dominant visitation frequencies) and the corresponding inflation factor (factors) are determined using one of the methods described in the Background section or previously determined values are retrieved. 3. Unique visitors (i.e. the core audience size)—U—are calculated using the formulas shown on FIG. 3 : formulas (1)-(2) are used when the visitation period is dominated by a single dominant frequency; formulas (2)-(3) when there are multiple dominant visitation frequencies.
[0039] If the site is equipped with access logging system that allows unambiguously identifying at least a portion of return visitors (e.g. via their unique login ID or unique cookie value, etc.) and assuming that all M unambiguously identified users are characteristic of the entire population of all users the Step 2 can be comprised of the following sub-steps— FIG. 5 :
1. For each such unambiguously identified user labeled with index i (1≦i≦M):
i. Maintain a record—the set A i (N)—of or cookie values (or network addresses) as they change with each visit. Thus A i (N) is a series of pairs {A N , t N } where A N is the visitor's cookie value (or network address) during the N-th visit that corresponds to the timestamp t N , N=0, 1, 2. . . . ii. Once the set A i (N) is constructed determine visitation frequency T k −1 as the inverse of the average of the difference between all consecutive timestamps in the visit history—the set A i (N):
[0000] T k −1 =<t N+1 −t N > −1 (4) where <> denotes averaging. 2. From large set of all the calculated visitation frequencies T k −1 select a smaller subset of K (K<<M) dominant visitation frequencies and bin the sets A i (N) together according to the selected dominant visitation frequency thus reducing the number of working sets down to K:
[0000] A i ( N ), 1≦ i≦M→A k ( N ), 1≦ k≦K ( K<<M ) (5) Note that the combined set A k (N) will contain all of the elements of the compounding sets A i (N) ordered by their timestamp t. 3. As the sets A k (N) are constructed by combining the sets A i (N) maintain the count M k of the number of visitor sets A i (N) that compound each set A k (N). From this number M k calculate the fraction q k of total visitors binned within each set A k (N) as:
[0000] q k =M k /M, 0< q k <1 (6) 4. From these K sets A k (N) build K new sets I k (N) where each element is the number of times the cookie value has changed (or the total number of unique network addresses) divided by N+1:
[0000] I k ( N )=( N+ 1) −1 Count_of_Unique( A k ( n ), 0≦ n≦N ) (7) Note that in the case of network addresses such as IP addresses I k ( 0 ) will be close to 1 (in fact C k ≡I k ( 0 )≈1), where as in the case of unique cookie counts I k ( 0 ) will be exactly 1 (C k ≡I k ( 0 )=1). In both cases properly constructed sets I k (N) will contain an increasing sequence of floating point numbers that correspond to the average number of the cookie value changes (of the average count of unique network addresses) per visit. 5. If the number of unambiguously identified visitors M k binned within each set I k (N) is statistically significant then individual inflation factors X k can be calculated as follows:
i. Fit X k (e.g. using least-squares) assuming I k (N)=1+X k N, N=0, 1, 2. . . . ii. Else assume that X i =X and fit X assuming that I(N)=1+X N, where I(N) is derived from the set A(N)—that is a combination of all sets A k (N)—according to equation (7). iii. As a variation sets corresponding to statistically insignificant visitor counts can be merged with the nearest statistically significant set and the estimation of X k is performed for the merged set as described in step-i.
[0050] Alternatively, the inflation factors X or X i can be determined before hand from mining large quantities of historical site access logs that can be obtained from search engines or hosting providers. Such logs are automatically accessible to providers offering user-identification services since these providers can simply mine logs of their customers for fine-tuning the inflation factor X based on visitation period, volume of the site traffic, content, geography, traffic patterns, etc.
[0051] Similarly, significant visitation frequencies T k −1 and the corresponding visitor fractions q k can be determined by mining the multitude of logs and adopting averages for the site's category.
[0052] Alternatively, for potentially better accuracy and/or for verification of the results a site can choose to conduct an online or offline marketing survey asking users how frequently they visit the site. The obtained marketing data can be used to estimate T k −1 , X k and q k .
[0053] Finally, if the site has a large number of visitors and is equipped with user identification system that relies on user registration (user sign-on) and/or cookie-tracking, better results can be achieved if the values of T k −1 , X k and q k are determined via mining of the historical site access logs focusing on unambiguously identified visitors. Such mining procedure and the determination of T k −1 , X k and q k can be performed periodically for improved accuracy of the results.
[0054] An example of a preferred system implementing the described method is depicted on FIG. 6 where Visitor ( 3 ) connects to Internet Site ( 1 ). A conventional Visitor Identification/Cookie-Tracking System ( 2 ) maintains Visit Log ( 4 ) where it records visitor's User ID (if any), Cookie Value, Network Address, access date and other relevant information. The Unique Visitors Estimation Subsystem ( 5 ) disclosed in this patent reads this information from the Visit Log ( 4 ), which it then uses to estimate the unique visitors count according to the disclosed method. For improved accuracy the Unique Visitors Estimation Subsystem ( 5 ) can interface with the optional Additional Log Repository ( 7 ) that can be used to derive more accurate estimates of X/X k , q k and T k . For ultimate flexibility the values of X/X k , q k and T k and other parameters can be entered manually into the Unique Visitors Estimation Subsystem ( 5 ) via the optional Configuration Interface ( 9 ). Finally, the numbers from both the traditional Visitor Identification/Cookie-Tracking System ( 2 ) and the invented Unique Visitors Estimation Subsystem ( 5 ) can be reported side by side using the Unique Visitors Reporting Interface ( 6 ). While it is sufficient to report only the unique visitors estimate produced by the Unique Visitors Estimation Subsystem ( 5 ) a value produced by the traditional Visitor Identification/Cookie-Tracking System ( 2 ) can also be reported for comparison.
[0055] An example of an alternative system implementing the described method is depicted on FIG. 7 where Visitor ( 3 ) connects to an Internet Site ( 1 ). In the alternative scenario the Internet Site ( 1 ) is not equipped with the elaborate Visitor Identification/Cookie-Tracking System ( 2 ) but instead is outfitted with the simple Visitor Access Logging System ( 8 ), which is be default available for virtually all Internet sites. The Visitor Access Logging System ( 8 ) maintains a Visit Log ( 4 ) where it records visitor's Network Address, access date and other relevant information. The Unique Visitors Estimation Subsystem ( 5 ) disclosed in this patent reads this information (focusing on Network Addresses) from the Visit Log ( 4 ), which it then uses to estimate the unique visitors count according to the disclosed method. The Unique Visitors Estimation Subsystem ( 5 ) requires input from the Configuration Interface ( 9 ) since it can no longer derive the X/X k , q k and T k parameters from the Visit Log ( 4 ) due to limitations of the simple Visitor Access Logging System ( 5 ), except in the case when the Internet Site ( 1 ) allows unambiguously identifying at least a portion of return visitors (e.g. via their Logon or user ID) and this unique visitor identifier is written to the Visit Log ( 4 ). For improved accuracy the Unique Visitors Estimation Subsystem ( 5 ) can interface with the optional Additional Log Repository ( 7 ) that can be used to derive more accurate estimates of X/X k , q k and T k than those provided by the Configuration Interface ( 9 ). Finally, numbers from the invented Unique Visitors Estimation Subsystem ( 5 ) and unique network address counts from the Visitor Access Logging System ( 8 ) can be reported side by side using the Unique Visitors Reporting Interface ( 6 ). While it is sufficient to report only the unique visitors estimate produced by the Unique Visitors Estimation Subsystem ( 5 ) unique network address counts from the Visitor Access Logging System ( 8 ) can also be reported for comparison.
[0056] Also, it follows from the equation (1) that for sampling interval t equal to one visitation period T the count of unique visitors U is exactly equal to the count of unique cookie values (U=I). In the case of network addresses the count of unique visitors U is approximately equal to the count of unique network addresses (U=I/C 0 ≈I). Thus simply counting unique network addresses/cookies during the sampling period t of one visitation period T gives a very accurate and simple estimate of unique visitors. This approach corresponds to yet another embodiment of this invention.
[0057] Although the description above contains much specificity, these should not be construed as limiting the scope of the invention but as merely providing illustration of the presently preferred embodiment of this invention. For example, it is conceivable that other forms of visitor identification will be developed in the future to supersede network addresses and cookies. As long as such newly introduced IDs are not guaranteed to be truly unique and/or are subject to change the method and system disclosed above still applies.
[0058] It will be appreciated that numerous modifications of the embodiments described can be effected within the scope of this invention.
REFERENCES
[0000]
1. M. Gery and H. Haddad: “Evaluation of Web Usage Mining Approaches for User's Next Request Prediction”, Fifth International Workshop on Web Information and Data Management (WIDM'03), IEEE, pp. 74-81, 2003
2. O. Nasraoui, H. Frigui, A. Joshi, and R. Krishnapuram, “Mining Web Access Logs Using Relational Competitive Fuzzy Clustering”, Eight International Fuzzy Systems Association World Congress (IFSA 99), IEEE, 1999
3. F. Giannotti, C. Gozzi, G. Manco, “Characterizing Web user accesses: a transactional approach to Web log clustering”, Proceedings of the International Conference on Information Technology: Coding and Computing (ITCC'02), IEEE, pp. 3-12, 2002
4. B. Thomas, “Burnt offerings [Internet]”, Internet Computing, IEEE, vol. 2, pp. 84-86, 1998
5. R. Iváncsy and S. Juhász, “Analysis of Web User Identification Methods”, International Journal of Computer Science, vol. 2, no. 3, pp. 212-219, 2007
6. M. Fomitchev, “On the Relationship Between Unique Users, Unique Cookies and Unique IP Addresses”, IEEE Transactions on Networking, 2009, submitted for publication
7. A. Lipsman, “Cookie-Based Counting Overstates Size of Web Site Audiences,” comScore, Press Release, http://www.comscore.com/press/release.asp?id=1389, 2007
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This invention comprises a method and system for estimating unique visitors for Internet sites that is more accurate than the existing unique cookie/unique address counting methods. The invented method relies on the count of unique user identifiers (such as network addresses or preferably cookies)—I—that can be obtained from an existing cookie tracking/user access logging system. The number of unique visitors U is calculated substantially as a ratio of the count of unique cookies (or unique network addresses) to the number of visits N times the inflation factor X plus constant on that is approximately one (exactly one in the case of cookies). The number of visits is calculated by multiplying the sampling period t to the visitation frequency T 1 minus one. The resulting estimate of the unique visitors is stable and does not diverge with sampling time unlike estimates directly obtained from the unique network address or unique cookie counts. The method is also applicable when there are multiple dominant visitation frequencies by accounting to the sum by all significant visitation frequencies. All key parameters of the method can be established before hand by mining a multitude of the site's historical visit logs and/or third party site access logs; the parameters can be corrected/calculated dynamically by mining the site's current access log (or current third party logs) while focusing on unambiguously identified visitors (such as return visitors identified by their login ID or unchanged cookie value).
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FIELD OF THE INVENTION
The present invention relates to welding masks or shields and, more specifically, to a novel mounting arrangement which permits safe and positive installation and removal of a lens pack containing the flash barrier lens system.
BACKGROUND OF THE INVENTION
The general construction and arrangement of welding masks or shields are not new. Typical prior art welding masks or shields are shown in various prior United States patents including the following: R. Malcolm, U.S. Pat. No. 1,904,993, issued Apr. 25, 1933; N. Anderson, U.S. Pat. No. 3,257,667, issued Jan. 28, 1966; J. N. Simpson et al, U.S. Pat. No. 3,458,865, issued Aug. 5, 1969; and Walters et al, U.S. Pat. No. 4,354,279, issued Oct. 19, 1982.
These prior art masks are generally of similar construction and comprise a shield section, preferably curved to conform somewhat to the face of the wearer. The shield section is preferably molded as a unit from an opaque, plastic, lightweight, stiff material. The shield is normally worn on the head of the user and includes some type of head band so it may be pivoted upwardly when not in use and easily moved to a face-protecting position.
When in a face-protecting position, the shield is faced forwardly of the wearer's face and extends around the side of the wearer's head so as to cover the head. The shield is usually provided with an enlarged, rectangular opening within which is mounted a lens assembly consisting of a plurality of panes, including, for example, an outer pane formed from a transparent material such as glass, an inner pane formed of similar material but which is tinted, colored or otherwise treated to eliminate the transmission of harmful radiation to the eyes of the wearer. Such radiation may be produced when contact is made between an energized welding rod and a work piece. The panes are usually separated by a gasket and are of a peripheral dimension conforming generally to the shape of the pocket-like viewing port in the shield but slightly undersized so that they may be easily assembled therein.
Typically, the panes of the lens assembly are oftentimes supported in the rectangular opening by means of a spring clip. The deficiencies of such an arrangement have been noted in U.S. Pat. No. 4,354,279. The mounting means described in that patent combines the insert and a spring clip into a unitary piece. An insert is provided which effectively blocks external light rays which might produce a corona or halo effect interiorly of the welding mask. A spring clip is provided which has horizontal leg portions pressing the insert against the lens pack.
The Walters et al design is admirably suited for providing an adequate corona barrier. Nevertheless, while the positioning of the lens pack is in a protected position to prevent penetration of harmful rays to the interior of the mask, the use of a spring clip is not totally satisfactory as a mounting means. The spring clip is somewhat clumsy and awkward to assemble and disassemble and can be inadvertently engaged to release the lens pack. What would be an improvement would be a system that is easy and quick to assemble and disassemble and will allow the lens pack to be removed only when a deliberate action by the operator is made but which cannot be accomplished unintentionally. Elimination of any wire which can come loose and harm the user is, of course, highly desirable.
SUMMARY OF THE INVENTION
The present invention relates to a welding mask assembly which comprises a shield section having a viewing port that is defined by a peripheral frame. The lens pack is mounted in the viewing port and a cover member covers the lens pack on the interior side of the shield. A cooperative locking means is provided between the cover member and the frame of the viewing port. The cover member is operable between a locked position which supports the lens pack in the port and a released position which permits removal of the lens pack. Movement between these two positions is achieved by lateral movement of the cover member relative to the frame in only one predetermined plane. Also, a biasing means is provided to normally bias the cover member away from that one predetermined plane where movement is permitted, so that normally the cover member is in a locked position supporting the lens pack in the port.
In one embodiment, the biasing means includes a pair of opposed biasing members such that both of them apply a bias to the cover member forcing it away from the plane. In this instance, either one of them is sufficient alone to bias the cover member away from the plane and, of course, when the cover is not in that plane, it cannot be moved to the released position. The locking means which cooperate with the cover member and the frame normally prevent lateral movement of the cover member relative to the frame. Since overcoming the bias on only one of the opposed bias members requires that the other bias means prevent movement of the cover in a lateral plane relative to the frame, the inclusion of a pivot means in the biasing means can transmit additional biasing force to the member which remains in the locked position.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other objects of the present invention and the various features and details of the operation and construction thereof are hereinafter more fully set forth with reference to the accompanying drawings, wherein:
FIG. 1 is a perspective view of an ultra-light welder's helmet, incorporating the combination lens, spring and flash barrier assembly of this invention as viewed from the front.
FIG. 2 is an exploded perspective view of the helmet and its associated lens, spring and flash barrier assembly as viewed from the rear, the adjustable head support bands and attachments being deleted for greater clarity of detail.
FIG. 3 is an enlarged, sectional, elevational view taken along the line 3--3 of FIG. 1 showing in detail the elements of the lens pack and cover member in cooperation with the frame as a stacked and locked operational mode of the device shown in FIG. 2. In addition the lens cover is shown in a removed position in phantom line and the spring elements of the biasing means are shown in phantom line illustrating the released position, when the lens cover may be removed.
FIG. 4 is an enlarged, rear elevational view of the combination of lens pack and biasing means along with the cooperating frame and cover assembly, as shown in FIG. 3, with certain parts broken away in section for greater clarity of detail.
FIGS. 5 and 6 are greatly enlarged, cut-away details of the specific cooperating locking means shown both in an open and closed position in FIGS. 5 and 6, respectively.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawings, and particularly to FIG. 1 thereof, there is shown a typical face-protecting device generally designated by the numeral 10. This device is particularly adapted for use by welders and is commonly referred to as a welding mask. The general configuration and arrangement of the welding mask are well-known and include a shield section 12, which is preferably curved to conform generally to the shape of the wearer, and includes the dome-like cover section 12a extending upwardly and rearwardly from the top of the shield section 12 and a lower section 12b extending downwardly and rearwardly from the lower edge of the shield section. These sections are gnerally integral and preferably molded as a unit from an opaque, plastic, lightweight, stiff material. The shield section 12 usually is connected to a head band, such as through head band supports 23, so that the mask can be pivoted between a face-protecting position covering the face and the ears of the user to a position above the head of the user when it is not in use.
The shield section 12 is usually provided with an enlarged viewing or opening port which is defined in FIG. 1 by peripheral wall 13 and which permits the user to observe his work. The peripheral wall 13, which is generally rectangular in shape in many cases, projects outwardly from the shield section 12 to accommodate a lens assembly as described herein and has an outwardly projecting generally rectangular peripheral wall section 13a and an inwardly directed wall section 13b projecting from the outer edge of wall 13b defining the viewing port. The wall 13a has an inward projection 13c formed integrally therewith (see FIG. 3) to define a pocket for the elements of the lens assembly.
Of primary importance in the lens assembly is a filter plate 14 which is adapted to eliminate the transmission of harmful light rays to the eyes of the wearer produced, for example, when contact is made between an energized welding rod and a work piece.
Shown in FIG. 2 is the lens pack which has been expanded. The shield section 12 is seen from the reverse side with head support openings 23a designated to show the location of the head band piece which is not shown in this view because it does not form a part of the present invention and would merely obstruct a line of sight to the features being described herein.
The lens assembly includes an outer pane 15 which is formed from a transparent material such as glass or impact resistant plastic and which is relatively inexpensive. This outer pane 15 is subjected to damage from sparking, smoke and other by-products of the welding operation and normally needs to be replaced fairly frequently. Since is is a relatively inexpensive piece, this outer pane 15 can easily be replaced when the lens pack is removed according to the present invention. Replacement of the outer pane 15 is easy for the welder to accomplish. In between the outer pane 15 and the filter plate 14 is a gasket 16 which is placed to prevent direct contact between the two glass-like materials. This is easily accomplished by the present invention. The pack, as shown in FIG. 2, includes the outer lens 15, the gasket 16, the filter plate 14 and a lens spring assembly 17. All of these internal components are contained in the frame 13 by the cover 18 as described hereinafter and can be removed, cleaned, and/or replaced without the use of tools.
In order to understand the operation of the locking mechanism of the preferred embodiment, reference is hereby made to FIG. 3 in which plane A--A is identified. This plane A--A is the only plane in which it is possible to have lateral movement of the cover 18 relative to the frame 13 towards a released position permitting removal of the lens pack from the port. The outer pane 15, gasket 16, filter 14 and lens spring assembly 17 are placed inside frame 13 and are held in place temporarily by gravity since the outer pane 15 and other components are larger than the port defined by frame 13. The cover shown in a removed position as 18a is then placed over the frame 13 and pressed directly down in a direction perpendicular to plane A--A. When this pressure is applied, both end 20 and end 22 of dual spring 19 are compressed and the dual spring 19 pivots about hinge 21.
As shown in FIG. 5, as the cover 18 is pushed in the direction of descending or vertical arrow V, the locking tab 24 is positioned inside slot 25 of frame 13. Movement of the cover 18 in the direction of arrow H along the horizontal will position the tab 24 to the closed end of slot 25. In the embodiment shown in FIGS. 5 and 6, the tab 24 has a point 27 which cooperatively locks into the edge 28 on slot 25. If pressure is then released so the biasing forces of dual spring 19 are allowed to function, the cover 18 is urged in the direction opposite arrow V so locking tab 24 is securely positioned in slot 25 by point 27 and edge 28. Because the slot 25 has been properly sized, the locking tab 24 is unable to move in any direction until the bias from dual spring 19 is overcome. While it remains in the position shown in FIGS. 3 and 6, the lens pack is maintained in a safe and secure position.
When it is desired to remove the lens pack for whatever reason, the operator can easily remove it. In order to accomplish this task, the bias of dual spring 19 must be overcome both at the first end 20 and at the second end 22. As long as locking tab 24 is securely held in slot 25 so the point 27 engages the edge 28, the case 18 cannot move in the direction shown by arrow 29 of FIG. 4. If pressure is applied to the cover 18 near 29, for example, the second end 22 of dual spring 19 would be compressed and the point 27b on the tab 24b would be separated from edge 28 of slot 25. Effectively, tab 24 would then be in plane A--A. Nevertheless, the cover 18 still cannot be moved and the lens pack cannot be removed because point 27a of the tab 24a is still engaged with edge 28a of slot 25a because the first end 20 of dual spring 19 has not been overcome.
If pressure is placed on the cover 18 at places adjacent both the first end 20 and the second end 22 of spring 19, then the entire cover is moved in the direction perpendicular to plane A--A and once the cover reaches the plane A--A, tab 24a is disengaged from slot 25a and tab 24b is disengaged from slot 25b so the cover member may now move between the locked position which supports the lens pack in the port to a released position which permits removal of the lens pack. This movement of the cover relative to the frame takes place only in plane A--A since it is only when the cover and frame are in this relative position that tabs 24a, 14b, 24c and 24d are disengaged from slots 25a, 25b, 25c and 25d. Movement of the cover permits removal of the cover to the position shown by 18a in FIG. 3. It is then a simple matter to lift out the lens spring assembly 17, the filter 14, gasket 16 and cover plate 15.
It is clear that the lens pack is secure when the cover 18 is cooperatively associated with the frame 13 in the locked position when tab 24 is engaged by slot 25. The dual spring 19 of the lens spring assembly 17 and the cushioning effect of gasket 16 prevent any relative movement. The welder can use the mask with the complete assurance that the lens pack will remain secure and undamaged. Even if the cover 18 is contacted through use, whether by intention or inadvertence, the lens pack will not move and will not become loose because of such contact. The cover member is only operable between its locked position which totally supports the lens pack and the release position which allows removal of the lens pack upon lateral movement of the cover when that cover is in that predetermined plane A--A. The user is totally protected from any springs or other protuberances which might be of concern if they were present. If desired, the front face of the latching cover 18 may be marked adjacent the arrow 29 with suitable indicia such as "TOP" to aid the user in positioning the latching cover to lock the parts in place. This orientation is necessary to ensure correct orientation and interaction between the bayonet slots 25 in inner wall 13c of the frame 13 and the latching pins or tabs 24a-24d of latching cover 18. As an additional visual aid in correctly orienting the latching cover, the top wall 18a may be made narrower than the opposite lower wall 18b, since the cover completely encloses all of the working mechanisms.
The novel mounting arrangement of the present invention also effectively shields or blocks out entrance of harmful light rays such as the ultra-violet radiation from a welding arc to the interior of the mask. More specifically, the mounting arrangement provides a dead end path to any light which may cause a halo effect in the peripheral area of the lens stack. More specifically, as best illustrated in FIG. 3, the frame 17a of spring assembly 17 is of angular profile and rectangular shape having right angularly disposed peripheral wall segments 17b, 17c which nest snugly in the walls 13 of the viewing port. Note the frame 17a corresponds closely dimensionally to the inside dimensions of the inner wall 13c defining the viewing port thereby blocking effectively the visible projection of radiation upon the peripheral walls of the viewing port.
While particular embodiments of the present invention have been illustrated and described herein, it is not intended to limit the invention and changes and modifications may be made therein within the scope of the following claims.
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In a welding mask assembly, a shield section having a viewing port defined by a peripheral frame; a lens pack mounted in the port; a cover member; and cooperating locking elements between the cover member and the frame. The cover member operates between a locked position supporting the lens pack in the port and a released position permitting removal of the lens pack upon lateral movement of the cover member relative to the frame in only one predetermined plane. A spring element normally biases the cover member away from the plane.
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PRIORITY
[0001] This application claims priority from German Patent Application No. DE 10 2005 030 600.4, which was filed on Jun. 30, 2005, and is incorporated herein by reference in its entirety.
TECHNICAL FIELD
[0002] The invention relates to a method for controlling a displacement element such as a vehicle window, a sunroof, a lift gate, a vehicle door or the like by means of a motor, preferably a DC motor, wherein parameter values, preferably in the form of a characteristic curve, which are stored by means of a learning run are compared with parameter values generated in real-time during operation of the motor and required for controlling same and as a function of which the motor is stopped or its rotational direction is reversed, and an apparatus for carrying out said method, and a method for generating parameter values of a learning run.
BACKGROUND
[0003] Automatic displacement elements are used in a wide variety of applications to enable the user to operate windows, doors and other closing devices conveniently and easily. For this purpose a DC motor is generally used which serves to drive the displacement element via an appropriate mechanism. Particularly in the automotive field, automatic window lifts and sunroofs as well as doors and lift gates have become commonplace and are already being fitted as standard in the vast majority of new cars.
[0004] However, particularly in the automotive field, the potential hazard of electric window lifts or sunroofs is already well recognized also, as numerous accidents involving them have already been recorded and given extensive media coverage.
[0005] If, for example, an object or body part is trapped between vehicle frame and electrically operated window or door, it may be subject to adverse effects or crushing because of the not inconsiderable motive force of the power actuator. Children, dogs or even adults can be injured by accidental actuation of electrical closing devices, such accidents even proving fatal in extreme cases. This is particularly the case with an automatic up/down feature whereby a brief touch of the switch suffices to open or close a window automatically. Tests have found that a closing force of even 100 Nm acting on the human neck can be life-threatening, and for small children the danger limit is as low as 30 Nm.
[0006] The experience of recent decades has therefore made it necessary to create devices for limiting the closing force, i.e. providing anti-trap protection, in order to stop the closing movement of motor-driven elements such as windows and doors if necessary and prevent such accidents from occurring. Although an EU directive specifies limiting the force of window lifts to 100 Nm, many automobile manufacturers are voluntarily aiming for a limitation to 10 Nm in order to make sure that any kind of crushing of fingers or other extremities is eliminated.
[0007] For this purpose any resistance to the closing movement of the window is registered by an open-loop controller, causing the motor-driven closing movement to be stopped or, in the case of intelligent control, even reversed by reversing the motor direction so that the trapped object or body part is immediately released. The window or door closing movement therefore lasts only until such time as an obstacle gets in the way.
[0008] A resistance is mainly detected by means of computer-assisted analysis of the motor current. If an object impedes the movement of the window pane, the motor is slowed down and the motor current increases. In such cases the controller which is measuring the motor current interrupts the supply of current or causes the displacement element, i.e. the window pane, to return in the opposite direction by reversing the polarity at the terminals of the DC motor via a suitable circuit.
[0009] Particular requirements are also placed on the software components of closed-loop control units, as the control system must not only detect a real obstacle, but also differentiate it from a defect such as icing-up or sticking of the power window due to dirt. Since in the latter case the resistance occurring must be overcome and the control unit must not be “fooled” by changing operating and environmental conditions, precisely operating and intelligent software solutions are required.
[0010] For driving window lifts, sunroofs, lift gates and other movable elements (hereinafter referred to globally as displacement elements), DC motors are normally used, whereby there is mounted on a motor shaft an at least two-pole rotor by means of whose rotation the motor's rotary motion is converted via Hall sensors into a Hall signal which is in turn used for speed calculation. The Hall sensor is a semiconductor device which produces a voltage as the result of current flow and an external magnetic field, said voltage increasing with the intensity of the current flow and the magnetic flux density.
[0011] As the Hall sensor changes its voltage level more quickly the faster the motor shaft rotates, the speed of the displacement element during its translational opening or closing movement can be determined, the motor speed being dependent on the voltage present and the necessary force which the motor must exert to produce the desired movement of the displacement element. Due to changing operating conditions such as temperature, gearing and various frictional resistances caused in particular by rubber seals, the force required to move the displacement element varies, which causes the speed of the system to vary while the voltage dropped across the motor remains constant.
[0012] As it is desired on the part of the industry to keep the displacement element speed constant throughout the opening and closing movement, the voltage applied to the motor is varied accordingly. In practical terms this means that the voltage must be increased equivalently the more force the motor requires to maintain the desired speed even under changed conditions. For this purpose the system is clocked via pulse width modulation (PWM), the input voltage supplying the motor being switched on and off at a high frequency of normally 20 kHz in short variable cycles. These cycles are termed the switching period T s , the ratio of the on-time t on to the off-time t off during such a switching period T s being variable as required.
[0013] If the on-time t on is increased, a larger arithmetic mean of the output voltage and therefore a higher output current is produced. In technical terms this is also known as a “duty cycle”, whereby if the on-time t on and off-time t off are of equal length a duty cycle of 50% is present, which means that the input voltage is also halved. If the on-time t on is only a quarter of the switching period T s , this is termed a duty cycle of 25% with consequently only a quarter of the input voltage being applied to the motor. The duty cycle and therefore the output of the motor is continuously controllable from 0 to 100%.
[0014] In known methods according to the prior art, the required displacement force which the motor needs to move the displacement element is calculated via the voltage and speed of the motor and stored in a nonvolatile memory. For this purpose a learning run is executed subject to clocking by means of constant PWM in order to determine the various frictional forces occurring in the system over the movement range of the displacement element. The frictional forces result primarily from the contact of the displacement element with seals and other mechanical transitions.
[0015] A learning run is necessary for each individual closing system because, in spite of standardization and mass production, every mechanical system proves to be unique and possesses individual characteristics which means that, due to manufacturing tolerances in the mechanism, it also does not behave in the same way in terms of its movement. Thus prior to initial commissioning of a new system, a one-off learning run is therefore performed and the characteristic data obtained is stored as a frictional or displacement force curve in order to then serve as a reference for all subsequent closing movements of the displacement element during normal operation.
[0016] For all the closing movements taking place in the future, the required PWM clocking is determined by means of complicated calculations on the basis of motor voltages and the associated stored reference data concerning the displacement forces which is obtained during the learning run in order to enable the different mechanical forces present at various points in time to be compensated. Comparison of the reference data with the forces currently present during a closing movement of the displacement element finally allows an object or body part to be detected and suitable control pulses to be triggered in order to stop the closing movement or reverse it by reversing the polarity of the direction of the motor. In practical terms, the exceeding of a particular permissible displacement force is therefore computationally registered and the motor drive is controlled accordingly in order to release the trapped object, the duty cycles for controlling the motor with constant speed being calculated on the basis of the characteristic values obtained from the learning run according to the displacement forces and not on the basis of the current speed actually occurring in the system.
[0017] As the learning run merely constitutes a simulation of the movement sequence of the displacement element as it occurs under learning run conditions (in the laboratory, workshop, etc.), but cannot allow for any current operating conditions and environmental effects present at the time of any displacement movements occurring subsequent to the learning run under real environmental conditions, it is also realistically impossible to match the speed to new circumstances.
[0018] One of the disadvantages of this method is that the reference data obtained during the learning run is also used as reference for all movements of the displacement element taking place in the future and the speed of the system is always reproduced in a rigid manner according to the calculation performed for the learning run. As the system's mechanism is subject to aging and changing environmental and operating conditions such as increased dust and temperature exposure, the speed of the displacement element cannot be kept constant and tends to vary from one path section to another, which also makes it difficult to define a precise closing force limitation, with the result that extremities trapped by the displacement element may in some cases suffer slight injury even with anti-trap protection provided. The irregularity of the displacement movement is likewise accompanied by undesirable audible and visual characteristics.
[0019] Moreover, the data recognition algorithm cannot reliably reflect all the operating ranges and physical conditions, such as changes resulting from mechanical aging, and requires complex adjustments for the simulation of same.
SUMMARY
[0020] The object of the present invention is therefore to avoid these disadvantages and to create a method and an apparatus for controlling a displacement element whereby quicker and more stable adjustment to suit current physical conditions can be achieved during system actuation. In addition, the method and apparatus according to the invention are designed to ensure a uniform speed of the displacement element throughout its movement, irrespective of the current operating conditions. The measures according to the invention are designed to provide anti-trap protection detection which is characterized by direct and realistic data utilization in order to enable the displacement mechanism to react rapidly and effectively in hazardous situations.
[0021] This object can be achieved by a method for controlling a displacement element such as a vehicle window, a sunroof, a lift gate, a vehicle door or the like by means of a motor, preferably a DC motor, the method comprising the step of comparing parameter values, preferably in the form of a characteristic curve, which are stored by means of a learning run with parameter values generated in real-time during operation of the motor and, depending on the result of the comparison, stopping the motor or reversing the motor rotational direction, wherein the speed of the motor is kept constant allowing for the mechanical forces actually occurring on the displacement element at the time of motor actuation and the parameter values generated in real-time are the result of closed-loop speed control causing the speed to remain constant and are used for controlling the motor.
[0022] The parameter values generated in real-time can be the ratio of the on-time of the motor to the off-time of the motor. If a defined difference between the stored parameter values and the parameter values generated in real-time is exceeded, the motor can be stopped and its drive motion can be preferably put into reverse. The parameter values stored by means of a learning run can be the ratio of the on-time of the motor to the off-time of the motor. The speed of the system can be maintained constant throughout the learning run.
[0023] The object can also be achieved by an apparatus for controlling a displacement element such as a vehicle window, a sunroof, a lift gate, a vehicle door or the like by means of a motor, preferably a DC motor, an open-loop control unit for motor clocking and a characteristic handler as well as a nonvolatile memory in which parameter values, preferably in the form of a characteristic curve, obtained in the course of a learning run are stored, wherein the open-loop control unit is preceded by a closed-loop control unit which causes the motor to operate at constant speed, the characteristic handler continuously comparing the parameter values of the open-loop control unit that are critical for motor control with the parameter values stored in the nonvolatile memory. The closed-loop control unit may comprise a PID controller.
[0024] The object can also be achieved by a method for generating parameter values of a learning run for use in the above mentioned method or apparatus, wherein the speed of the motor can be kept constant by means of a closed-loop control unit, preferably a PID controller.
[0025] The travel path of the displacement element can be subdivided into a plurality of sections within which an average of the parameter values required for controlling the motor while its speed is maintained constant is calculated, the difference between the current parameter value and the previously stored parameter value being stored in the nonvolatile memory at the end of the section. The totality of all the stored parameter values can be stored as a characteristic in the nonvolatile memory. The parameter values can be the ratio of the on-time of the motor to the off-time of the motor.
[0026] Whereas open-loop motor control systems according to the prior art use stored parameter values, namely the above-described displacement force characteristic, in order to control the motor via complicated calculations so that it runs at a constant speed, in the method according to the invention the motor speed is closed-loop controlled using parameter values generated in real-time and which allow for the displacement forces actually required.
[0027] The speed of the motor is kept constant taking into account the mechanical forces actually occurring on the displacement element at the time of motor actuation, the parameter values generated in real-time being the result of closed-loop speed control causing the speed to remain constant and being used for controlling the motor.
[0028] For this process a closed-loop control unit is used, preferably a PID controller which keeps the rotation speed constant during the learning run and also during operational use. By means of said closed-loop control unit, the output of the motor and therefore the closing speed of the displacement element can now be quickly and reliably adapted to actual higher frictional resistances which in the case of a car window lift occur primarily at the beginning and end of a closing movement as a result of contact between the glass and the window sealing lips, the closed-loop control unit causing an open-loop control unit to generate the parameter values required for controlling the motor. In this way a duty cycle meeting the stated requirements can be provided.
[0029] Obviously, instead of the PID controller other closed-loop control systems can likewise be used for the purpose of speed regulation such as proportional and integral controllers together with their modifications and control circuits specifically designed to solve a particular problem, without departing from the inventive idea.
[0030] According to the characterizing feature of claim 2 , the parameter values generated in real-time for controlling the motor output are registered in the form of duty cycle values which are stored preferably as a duty cycle characteristic corresponding to the sluggishness or ease of movement of the displacement element as a result of the frictional resistance. As already explained above, the duty cycle is the ratio of the on-time of the motor to the off-time of the motor or, more precisely, the ratio of the on-time t on to the switching period T s , said switching period T s comprising one cycle of off-time t off and on-time t on . By means of appropriate variable clocking of the motor, a constant speed of the displacement element during its actuation can thus be achieved in spite of the different displacement forces required. This speed homogenization also provides auditory benefits, as the closing noise of the displacement element is now more evenly spread. Likewise the sight of a displacement element moving at a uniform speed is more visually acceptable particularly in the case of a car window lift.
[0031] As a result of the characterizing features of claim 3 , the motor is stopped and its drive direction preferably reversed if a defined difference between the stored parameter values and the parameter values generated in real-time is exceeded. In this way, an object or body part trapped by the displacement element can be detected in a direct and reliable manner.
[0032] By comparing the duty cycle characteristic currently being obtained with the characteristic already correctly stored during the learning run in respect of a constant speed, any obstruction in the path of the displacement element can be detected more quickly and more reliably. As there is now no need to calculate displacement forces required to overcome frictional resistances, the duty cycle set by the PWM controller can be compared directly with the values from the characteristic obtained in the learning run.
[0033] According to the characterizing features of claim 4 , the parameter values stored by means of the learning run are likewise the ratio of the on-time of the motor to the off-time of the motor, i.e. they are duty cycle values or a duty cycle characteristic. Directly comparing duty cycle values or characteristics permits direct data analysis using a simpler algorithm than that used in existing known methods according to the prior art. Any desired system speed can be defined, which means that an atypical or arbitrary speed characteristic can also be generated if required for particular applications.
[0034] Even during the learning run the speed of the system is controlled in accordance with the characterizing features of claim 5 in order to maintain it constant and thus obtain a realistic characteristic in respect of the displacement element's closing speed which is used as a reference for all subsequent closing movements. For all other closing movements of the displacement element following the learning run the speed is again maintained constant via the closed-loop control unit and the currently obtained duty cycle is compared directly with the stored duty cycle by a characteristic handler.
[0035] The characterizing features of claims 6 and 7 apply to an apparatus arrangement for implementing the described method, claim 6 providing that the open-loop control unit clocking the motor is preceded by a closed-loop control unit which causes the motor to be operated at constant speed, there being provided a characteristic handler which continuously compares the open-loop control unit's parameter values critical for motor control with the parameter values stored in a nonvolatile memory. The characteristic handler is disposed in a superordinate manner to all the other open- and closed-loop control units and can directly check the motor output control at any time in order to take the described action to stop the motor or reverse the drive motion.
[0036] According to the characterizing features of claim 7 , the closed-loop control unit described comprises a PID controller. By providing a permanently active PID controller, a desired speed of the displacement element can always be adjusted to suit the circumstances even after modification of the mechanism as the result of aging or changed operating conditions and kept constant at all times. In accordance with the comments made in connection with claim 1 , it is self-evident that other closed-loop control systems can likewise be used in place of the PID controller without departing from the inventive concept.
[0037] The apparatus according to the invention permits a simpler and direct data computation algorithm and the quality of the anti-trap protection can be set by means of the PID controller via the accuracy of the speed control system. This means that, the more accurately the PID controller is set, the more quickly it is possible to react to speed changes as the result of trapping. Any crushing of limbs can be reliably eliminated by accurate setting of the closed-loop control unit.
[0038] The characterizing features of claims 8 to 11 describe a method corresponding to the preceding claims for generating parameter values of a learning run.
[0039] In accordance with the characterizing features of claim 8 , the motor speed is kept constant during the characteristic-determining process by means of a closed-loop control unit, preferably a PID controller. In contrast to the prior art where a force profile over the travel path of the displacement element is stored before a duty cycle is calculated therefrom, with the system according to the invention a duty cycle corresponding to the frictional forces occurring is generated as early as the learning cycle with the speed already being kept constant. Consequently, in accordance with the characterizing features of claim 9 , a plurality of duty cycle values corresponding to different sections of the path traversed by the displacement element during its closing movement are calculated, an average of those parameter values required for controlling the motor while its speed is kept constant being calculated. For this purpose, at the end of each section the difference between the current parameter value and the previously stored parameter value is stored in the nonvolatile memory.
[0040] In accordance with the characterizing features of claim 10 , the totality of all the stored parameter values, which are likewise duty cycle values in accordance with the characterizing feature of claim 11 , are stored as characteristics in the nonvolatile memory. In practical terms this provides a ready-made predefined duty cycle for controlling the motor with constant speed while allowing for the specific mechanical properties of the system.
BRIEF DESCRIPTION OF THE DRAWINGS
[0041] The invention will now be explained in greater detail with reference to an exemplary embodiment in which:
[0042] FIG. 1 schematically illustrates a control circuit according to the invention
[0043] FIG. 2 shows pulse width modulation (PWM) clocking of the system
[0044] FIG. 3 schematically illustrates a duty cycle
DETAILED DESCRIPTION
[0045] FIG. 1 shows a control circuit as used in the method according to the invention, comprising a motor 1 , a closed-loop control unit 2 and a characteristic handler 3 . In this system the motor 1 is used to drive a displacement element 4 via an intermediate mechanism (not shown). The displacement elements 4 are openable and closable windows, doors or other closing devices, the use of the system according to the invention in the automotive industry being described in the present application with particular reference to power windows or sunroofs. However, the system according to the invention can also be used just as well, and prove advantageous, in building and gardens, for garage doors or automated closing devices generally.
[0046] The illustrated combination shows that the motor 1 is clocked mainly by means of pulse width modulation (PWM) via the open-loop control unit 2 (see FIG. 2 ). Output control by means of PWM allows the displacement force and speed required on the part of the motor to move the displacement element 4 to be randomly controlled. For this purpose the input voltage supplying the motor is switched on and off at high frequency in brief switching periods T s in the known manner. By extending the on-time ton a larger arithmetic mean of the output voltage and therefore a larger output current is achieved. The output of the motor is continuously controllable from 0 to 100% via this ratio known as a “duty cycle”. Purely by way of example, FIG. 2 shows the resulting square-wave signal 8 , the on-time t on here accounting for 50% of the switching periods T s , i.e. a duty cycle of 50%.
[0047] According to the invention, a closed-loop control unit 9 is used which keeps the speed in the system constant during a learning run and also during operational use. Although in the example a PID controller is proposed as closed-loop control unit because of its optimum and rapid control characteristics, another kind of controller can likewise also be employed. The PID controller reacts quickly and reliably to effective higher frictional resistances which the displacement element 4 has to overcome especially at the beginning and end of a closing movement as a result of mechanical transitions and adapts the output of the motor in such a way as to ensure a constant closing speed of the displacement element 4 .
[0048] The learning run must be carried out prior to initial commissioning of a new system, as each individual mechanical system always possesses a certain range of uncertain parameters and an individual characteristic as a result of manufacturing. The obtained parameter values characterizing the particular mechanical system according to the frictional resistances are stored as a duty cycle characteristic 5 in a nonvolatile memory 10 in order to serve as reference for all future closing movements of the displacement element 4 during operational use.
[0049] Such a duty cycle characteristic 5 is shown by way of example in FIG. 3 . Here the entire path over which the displacement element 4 travels when actuated is subdivided into small sections 6 and within each of these sections 6 an average of the above described duty cycle required is computed. Thus for each position of the displacement element 4 in its displacement path an output value is calculated with which the motor 1 must be controlled in order to overcome the particular frictional resistances while maintaining a constant displacement speed and to move the displacement element 4 to the end position provided. At the end of each section 6 , the difference between the current duty cycle value and the previous duty cycle value is stored so that a characteristic 5 is eventually produced from the total number of duty cycle values obtained at the predefined positions.
[0050] When the learning run has been completed, it is now the task of the characteristic handler 3 , for all future actuations of the displacement element 4 , to compare these stored duty cycle values with the current duty cycle values occurring on the relevant sections 6 . If a defined permissible deviation from the stored duty cycle characteristic 5 and therefore from the normal case provided by the learning run is exceeded, any obstacle trapped by the displacement element 4 is immediately detected by the characteristic handler 3 . In such cases appropriate action is taken by the characteristic handler 3 to eliminate the trapping hazard. This action can be either to stop the motor 1 or reverse is drive motion, and can also include suitable audible or visual signals.
[0051] The reference numeral 7 in FIG. 3 relates to the starting position for the comparison of the current duty cycle with the duty cycle characteristic 5 .
[0052] During all the closing movements of the displacement element 4 following the learning run, it is also the task of the PID controller to keep the speed constant. Whereas with known methods according to the prior art the necessary displacement force required by the motor 1 to move the displacement element 4 is calculated via the voltage and speed of the motor 1 and compared with stored displacement forces, in the system according to the invention any such displacement force calculation is no longer necessary, as the PID controller continuously monitors the speed of the motor 1 .
[0053] The duty cycle produced by the open-loop control unit 2 , which is created on the basis of the closed-loop control unit 9 , can now be compared directly with the duty cycle characteristic obtained in the learning run.
[0054] In this way, even after mechanical alteration as the result of aging or changing operating conditions, a desired characteristic of the displacement element 4 can always be approximated accordingly.
[0055] Now the trapping sensitivity can be adjusted using the PID controller via the accuracy of the speed control system.
[0056] The reliable speed regulation is accompanied by a more acceptable (because more uniform) closing noise of the displacement element 4 .
LIST OF REFERENCE NUMERALS USED
[0000]
1 Motor
2 Open-loop control unit
3 Characteristic handler
4 Displacement element
5 Duty cycle characteristic
6 Sections
7 Starting position
8 Square-wave signal
9 Closed-loop control unit
10 Memory
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In order to create a method and an apparatus for anti-trap protection detection for displaceable window and door elements by means of which faster and more stable adjustment to current physical conditions can be achieved during system actuation, in the system the motor ( 1 ) is controlled using parameter values generated in real-time using a closed-loop control unit, preferably a PID controller, to keep the speed in the system constant during a learning run and during operational use and to ensure timely trapping detection.
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FIELD OF THE DISCLOSURE
[0001] The invention relates to a downhole logging tool.
BACKGROUND OF THE DISCLOSURE
[0002] As is well known, prospecting for minerals, hydrocarbons such as oil and gas, and other natural resources of commercial value is economically an extremely important activity. For various reasons those wishing to extract resources from below the surface of the ground or the floor of an ocean need to acquire as much information as possible about both the potential commercial worth of the natural resources in a geological formation and also any difficulties that may arise in extracting them to surface locations at which they may be used.
[0003] Techniques of logging of subterranean formations have developed for the purpose of establishing, with as much accuracy as possible, information as outlined above both before extraction activities commence and also while they are taking place.
[0004] During exploratory drilling operations, a hole is drilled from a surface location to a location underground near where the prospective resource is located. The resulting borehole may extend for several thousand or tens of thousands of meters from a surface location.
[0005] Drill pipe is typically a hollow, thick-walled, steel piping used on drilling rigs to facilitate the drilling of a borehole/wellbore. Drill pipe consists of numerous pieces, sometimes called “stands”, screwed one to another. Each stand is approximately ten meters long. Usually a stand has external male threads at one end and female threads in the internal diameter of the other end. The male threads of one stand are engageable with the female threads of another stand, thereby allowing joining of the stands together.
[0006] Normally while borehole drilling is carried out, a compound string of drillpipe stands is used in order to drive a rotatable drill bit mounted at the end of the pipe in contact with the geological formation being drilled.
[0007] As the drill bit works its way down into the ground and the borehole length increases, the drill pipe is repeatedly extended by adding new stands to its upper end. As a result long lengths of drillpipe may be inserted into boreholes as they are formed.
[0008] Broadly stated, logging involves inserting a logging tool, also known as a sonde, into a borehole or other feature penetrating a formation under investigation; and using the sonde to energize the material of the rock, etc., surrounding the borehole in some way. Such passage of the energy alters its character. The logging tool, that is capable of detecting energy, is intended then to receive emitted energy that has passed through the various components in the rock before being recorded by the logging tool.
[0009] Typically the logging tool is formed as an elongate, rigid cylinder that may be e.g. one to five meters long.
[0010] Wireline, as is well known in the art, is an armored cable that may be used for the purposes of lowering a logging tool into the borehole, or supporting the tool while it is being withdrawn upwardly along a borehole or well during logging. The logging tool is located at the end of the wireline. Logging measurements are in one known method taken by lowering the wireline including a logging tool attached as aforesaid to a prescribed depth and then raising it out of the well while operating the logging tool. Wireline is capable of electronically telemetering data from various types of logging tool from downhole to surface locations; and also of sending electronic commands to connected downhole equipment. In some situations however it is not possible or desirable to maintain the wireline connected to the logging tool following deployment of the latter.
[0011] Wireline drop-off is a conveyance system that allows for openhole data acquisition while tripping (i.e. the act of pulling the drill pipe out of the hole or replacing it in the hole). In this conveyance technique, a logging tool powered by a battery having a memory function is conveyed downhole by wireline through the drill pipe and hangs into the openhole on a no-go at the bottom of the drill pipe.
[0012] When drilling has reached total depth (the planned end of the well measured by the length of pipe required to reach the bottom), the wireline is released into the drill pipe. Typically there is a landing collar in the internal wall of the drill pipe, located near the mouth of the final (i.e., most downhole) stand, which receives a landing ring located on and protruding outwardly from the tool. The engagement of the landing ring and collar secures the tool and pipe one to another. When this engagement has occurred, the wireline is removed from the well.
[0013] The result of this sequence is that part of the logging tool protrudes beyond the end of the drill pipe and therefore is exposed in a way that permits logging of the formation. A further part of the logging tool remains inside the drill pipe and defines the described landing ring connection to the drill pipe.
[0014] To withdraw the drill pipe, the stands at the surface are unscrewed one by one from each other to separate them as the drill pipe is pulled upwardly in discrete steps. As a result the drill pipe is gradually withdrawn from the borehole. A dropped-off logging tool therefore moves towards the surface with the pipe, taking records (well logs) of the formation along the way.
[0015] Each time a drill pipe stand is to be removed from the upper end, the withdrawal operation is interrupted while unscrewing of the drill pipe takes place.
[0016] The protruding nature of the landing ring on the tool may prevent it from entering drill pipes having a small internal diameter.
[0017] Prior art wireline drop-off techniques only enable the tool to log the openhole beyond the landing ring into which the tool protrudes. This limits the length of the openhole where formation data could be acquired. It would be desirable to log openhole that is well beyond the end of the drillpipe.
[0018] Sometimes it is desirable to re-log the formation to prove the accuracy and repeatability of the measurements, a technique that is commonplace in conventional wireline logging.
[0019] Furthermore, should the drill pipe become stuck in the wellbore a common technique to free it is to rotate and reciprocate the drill pipe. Reciprocation, e.g., moving the pipe up and down, is not possible with logging tools hanging out of the end of the pipe.
SUMMARY OF THE DISCLOSURE
[0020] A way to solve the above problems is to have moveable retractable arms which enable the tool to become engaged with a landing surface, if so desired; or allow the tool to go beyond a drill pipe landing ring, into openhole. Such arms do not extend beyond the external cylindrical logging tool body in the retracted position. Consequently the overall external diameter of the logging tool is smaller than in prior art tools having permanently protruding landing parts. This therefore allows the tool to enter and pass through drill pipes that have a small diameter and for the tools to be latched (or re-latched) within the drill pipe using a wireline to latch them at a second position that ensures they do not extend beyond the end of the pipe
[0021] However, there is a tendency for such arms not to lock in their maximally extended position and hence collapse into a compressed (retracted) position under the influence of e.g. fluid pressure or other forces acting on the arms in the drill pipe. There is therefore a need to improve the stability of the arms in use.
[0022] According to a first broad aspect of the invention, there is provided a logging tool or logging tool sub for downhole use comprising an elongate logging tool body; at least one reaction member that is moveable between a retracted position in which it protrudes transversely no further than the extent of the logging tool body and an extended position in which the reaction member protrudes transversely beyond the logging tool body; and a releasable locking mechanism for locking the reaction member in the extended position.
[0023] The presence of retractable and extensible reaction members means that the logging tool or logging tool sub advantageously may selectively be caused to land on a landing component, such as a landing ring or shoulder of drillpipe; or pass freely by any such landing feature with the result that the logging tool or logging tool sub may travel beyond the end of drillpipe into open hole. The inclusion of a locking mechanism means the/or each reaction member may selectively be stabilized in use against forces tending to cause the reaction member(s) to retract. This is desirable because a well can kick due to random gas or oil pressure events forcing the logging tools back into the drill pipe. When the latching mechanism reverts to being closed the logging tools will disconnect from the drill pipe.
[0024] In some preferred embodiments of the invention the logging tool or logging tool sub includes a plurality of reaction members disposed at mutually spaced locations about the logging tool body. Such an arrangement beneficially permits landing of the logging tool or logging tool sub by way of multiple points of contact with one or more landing features of drill pipe. Such an arrangement is stable and secure.
[0025] Preferably the/or each reaction member is drivable at least between the retracted and extended positions by a cam and follower arrangement. In practical embodiments of the invention the/or each reaction member is also drivable in the reverse direction between the extended and retracted positions by way of the cam and follower arrangement.
[0026] Also, preferably the/or at least one said reaction member is or includes such a cam follower.
[0027] In one embodiment of the invention, the/or each said reaction member is drivable at least between the retracted and extended positions by a rack and pinion arrangement.
[0028] Preferably, the or at least one said reaction member is or includes a rack of a said rack and pinion arrangement.
[0029] The/or at least one said reaction member optionally may be or include a dog that is engageable with a latching part of a landing component of a section of drill pipe.
[0030] Such arrangements are beneficially effective in assisting secure landing of the logging tool or sub.
[0031] In another preferred embodiment of the invention, the/or at least one said reaction member is or includes at least one arm that at a first location is pivotably secured to the logging tool body so as to be extensible therefrom and compressible towards the logging tool body, and at a second location spaced from the first location is pivotably secured to a locking member forming part of the locking mechanism; and the locking mechanism further includes a stop member that is fixed or fixable relative to the logging tool body; the locking member defining a moveable end that is remote from the second location and is moveable relative to the arm between at least a first position in which force tending to compress the arm towards the logging tool body causes the moveable end to move away from the stop member, and a second position in which force tending to compress the arm towards the logging tool body causes the stop member to resist movement of the locking member thereby preventing compression of the arm towards the logging tool body.
[0032] Having moveable retractable arms enables the logging tool to become engaged with a landing surface or allows the tool to go beyond a drill pipe landing ring, into openhole. It is possible to keep the tool in the desired depth by means of the arms that provide stability to the tool. Once the logging tool has reached a desired downhole depth, the apparatus of the invention provides a locking mechanism. This locking mechanism keeps the arms locked in their extended positions even when compressional forces acting on the arms urge them to close back towards the logging tool. The ability of the arms to be maintained in the extended position is therefore also independent of the strength of the driving mechanism of the logging tool system.
[0033] Preferably, the logging tool includes a moveable member that is moveable towards and away from the stop member, the moveable end of the locking member being pivotably secured to the moveable member whereby when the locking member adopts the second position force tending to compress the arm towards the logging tool body urges the moveable member into engagement with the stop member.
[0034] In a preferred embodiment of the invention, the logging tool body includes a hollow interior accommodating the stop member and the moveable member and the locking member extends via an aperture to interconnect the arm and the moveable member.
[0035] Being housed inside the logging tool body, the stop member, the moveable member and the locking member are protected against the downhole environment. Also the exterior dimensions of the logging tool are kept as compact as possible.
[0036] Preferably, in the first position, the locking member lies to a first side of a normal to a longitudinal axis of the logging tool body, and in the second position the locking member lies to a second, opposite side of the normal.
[0037] It is preferred that the locking member is rigid whereby movement of the locking member between the first and second positions causes the arm to extend from the logging tool body to a maximal extent.
[0038] Further, preferably the logging tool body includes a recess within which the arm is receivable when in a compressed position.
[0039] In a preferred embodiment of the invention, the pivoting of the arm exposes a surface that is engageable with one or more landing surfaces of a further component.
[0040] Conveniently, the engagement of the resulting exposed surface of the arm with a landing surface of a further component causes pressing of the exposed surface and the landing surface together so as to stabilize the arm in an extended position.
[0041] Preferably, the logging tool includes a pivot pin through which the arm is pivotably secured to the logging tool body, extending inside the recess.
[0042] Also, preferably there are provided three moveable arms each supported by a locking member, at equiangular spacings about a circumference of the logging tool body, which typically is cylindrical.
[0043] The inventors have found it desirable to have three moveable landing extensions but the invention is not limited to this number. More or fewer or arrays of moveable landing extensions therefore may be employed, in regular or irregular patterns.
BRIEF DESCRIPTION OF THE DRAWINGS
[0044] There now follows a description of preferred embodiments of the invention, by way of non-limiting example, with reference being made to the accompanying drawings in which:
[0045] FIG. 1 is a transparent, three-dimensional side view of a logging tool according to the invention inserted into drill pipe and having arms in an extended un-locked position;
[0046] FIG. 2 shows the FIG. 1 arrangement wherein the arms are in a maximally extended locked position;
[0047] FIGS. 3A to 3J form a series of schematic drawings showing how movement of the locking member locks the arms in a maximally extended position.
[0048] FIG. 4A is a three-dimensional perspective view of a logging tool according to an embodiment of the invention having a cam and follower arrangement.
[0049] FIGS. 4B and 4C depict a sectional view of the logging tool of FIG. 4A dissected along the line a.
[0050] FIG. 5A is a three-dimensional perspective view of a logging tool according to an embodiment of the invention having a rack and pinion arrangement.
[0051] FIGS. 5B and 5C depict a sectional view of the logging tool of FIG. 5A dissected along the line R.
DETAILED DESCRIPTION
[0052] FIG. 1 shows, in bold lines, a superimposed schematic representation similar to that depicted in FIGS. 3A to 3J . However, the schematic lines of FIGS. 3A to 3J do not form part of the embodiment of FIG. 1 .
[0053] Referring to FIGS. 1 and 2 of the drawings, there is shown a logging tool or logging tool sub 10 that as is commonly the case has an elongate, hollow cylindrical body 11 . Parts of the logging tool intended to energize a subterranean formation or receive logging signals from underground rock are for clarity not shown in the figures. These features may take a wide range of forms that are known to the person of skill in the art.
[0054] The cylindrical body 11 of the logging tool 10 supports reaction members that in the illustrated embodiment are three pivotably deployable arms 12 secured on the exterior of the cylindrical body 11 in the manner described below.
[0055] In the preferred embodiment of the invention shown in FIGS. 1 and 2 , three arms 12 are provided equiangularly spaced about the external circumference of the logging tool. As a result of the orientation of the logging tool in the figures, only two of the arms 12 are visible.
[0056] The arms 12 lie near to the in-use uphole end of the logging tool 10 so that a major part of the length of the tool 10 extends in a downhole direction from the circumference at which the arms 12 are secured. This feature is of benefit when deploying the tool 10 in a drop-off (or similar “tool hanging”) manner so that part of the tool protrudes beyond the open end of drill pipe in a borehole.
[0057] However, other numbers and patterns of the arms 12 are possible within the scope of the invention. It is not essential that the arms 12 are equiangularly spaced about a circumference of the tool 10 , or that they are secured at a common circumference. Indeed various irregular patterns of the arms 12 are possible but the regular arrangement shown is preferred because (a) it permits even accommodation of forces when the arms 12 engage a drill pipe landing ring; and (b) landing of the tool 10 may be effected reliably and repeatably as a result.
[0058] The arms 12 are elongate, essentially rectangular members that extend parallel to the longitudinal axis of the logging tool 10 . As shown in FIG. 1 , the arms 12 are received within respective essentially rectangular recesses 13 that are aligned in register with the arms 12 and are dimensioned so that the arms 12 are neatly receivable retracted inside in them. The depth of each recess 13 is such that when the arms 12 are in the retracted position they protrude outwardly no further than the material of the cylindrical body 11 , and in preferred embodiments of the invention lie flush with the exterior of the body 11 . In FIG. 1 , however, the arms are illustrated in a slightly different position and are only partly retracted.
[0059] At its in-use, uphole end each recess 13 includes secured therein a transversely extending pivot pin 14 that extends across the recess from one major side to the other, opposite side.
[0060] Each pivot pin 14 perforates one of the arms 12 near its uphole end and retains it pivotably captive relative to the cylindrical body 11 . The dimensions of the parts are such that the arms 12 may pivot between a compressed position and an extended position. As a result of pivoting about the pivot pins 14 , the uphole ends of the arms 12 retract slightly into the associated recesses 13 and the downhole ends protrude noticeably beyond the exterior of the cylindrical body 11 .
[0061] The in-use, most downhole ends of the arms 12 are formed as exposed surfaces 16 that are engageable with drill pipe landing rings of conventional designs.
[0062] As illustrated, the pivot pins 14 are secured in chord bores 17 formed in the material of cylindrical body 11 . Each pivot pin 14 may be e.g., a press fit at either end in a pair of such chord bores 17 , so that the pivot pin 14 spans the recess 13 in which it is fixed from one major side to the other. However, other methods of securing the pins 14 are possible within the scope of the invention.
[0063] Near the exposed surface 16 at one end of each arm 12 , there is pivotally connected one end of a moveable locking member 18 . The other end 19 of the locking member 18 is pivotally fixed to a moveable member 21 .
[0064] In a preferred embodiment of the invention, the locking member 18 is made of rigid materials but the invention is not limited as such.
[0065] Thus, it is possible for example for one or more of the locking members 18 to be resiliently deformable (e.g., through the incorporation of a spring-biased hinge mid-way between its ends). Such a locking member would resist forces tending to compress the arms 12 into the recesses 13 up to a limit determined by the spring force acting at the hinge. A compressive force exceeding the resilience of the locking member 18 then would cause the arms 12 to adopt the retracted position even when they are locked as described below.
[0066] Within the hollow interior of the logging tool 10 , an elongate stop member 22 additionally extends along the longitudinal axis of the body 11 . Stop member 22 in the illustrated embodiment of the invention is formed as an elongate, fixed rod one free end of which is engageable by the moveable member 21 . In other embodiments, however, the stop member 22 may take other forms.
[0067] Moveable member 21 lies inside, and is longitudinally moveable along, a hollow bore 27 extending inside the body 11 of the logging tool 10 parallel to its longitudinal axis. In the preferred embodiment shown the bore 27 is concentric with the cylinder that is the logging tool body 11 ; but in other embodiments of the invention this need not necessarily be the case, and e.g., an off-center moveable member may be used.
[0068] The moveable member 21 preferably is essentially cylindrical as illustrated but this need not necessarily be the case, and other cross-sections are possible. In such cases the cross-section of the hollow bore 27 may be altered accordingly.
[0069] The moveable member 21 as illustrated is slideably moveable inside the hollow bore 27 . In other embodiments of the invention, however, movement of the moveable member 21 may be effected through a phenomenon other than sliding. Furthermore, it is not strictly necessary that movement of the moveable member 21 is longitudinal relative to the logging tool body 11 . Thus, it is possible to envisage variants of the invention in which e.g. rotational movement of the moveable member 21 is possible. In such an arrangement, it may be desirable for the locking members 18 not to be permanently connected to the moveable member 21 . Examples of such variants are described below with reference to FIGS. 4 and 5 .
[0070] As a result of the pivotable connections at the ends of the locking members 18 , the latter are moveable as the arms 12 and moveable member 21 move.
[0071] Furthermore, as noted, the moveable member 21 lies inside the interior of the logging tool body 11 whereas the pivotable connection of each locking member 18 and its associated arm 12 lies in a recess 13 , externally of the logging tool body 11 .
[0072] In order to accommodate both the connection between each arm 12 and the moveable member 21 a respective, through-going perforation 23 is formed in the walls of each recess 13 . In the embodiment illustrated each perforation is in the form of an elongate slot that extends parallel to the center axis of the logging tool body 11 . In other arrangements however other shapes of the perforations are possible.
[0073] Depending on the sizes and shapes of (in particular) the recesses 13 , the perforations 23 and the moveable member 21 , one or more parts of the moveable member 21 may at certain points in its range of movement protrude via the perforations 23 into the recesses. In the embodiment of the invention illustrated in FIGS. 1 and 2 , however, the ends of moveable member 21 at which the locking members 18 attach are shaped, e.g. flattened, so as to avoid protrusion of the moveable member 21 via the perforations 23 .
[0074] Regardless of whether the moveable member 21 protrudes as described, it is advantageous for each pivotable connection of a locking member 18 to the moveable member 21 optionally to lie as shown inside a respective further recess 24 formed in the surface of the moveable member 21 . This protects the pivot against damage and assists the member 21 to move freely inside the logging tool body 11 .
[0075] FIGS. 3A to 3J illustrate, by way of schematic drawings, the movement of the arms 12 when the moveable member 21 moves in direction X (i.e. from right to left). Such movement of the moveable member 21 may be effected in a variety of ways as will be known to the person of skill in the art.
[0076] FIG. 3A shows the locking member 18 initially forming an angle of 61° (in the preferred embodiment described, although this choice of starting position may be varied within the scope of the invention) with a normal 26 to the longitudinal axis of the logging tool on one side. The size of the angle is for illustration purposes and the angle formed, as depicted in FIGS. 3A to 3J , can range from 0° to 90°.
[0077] As the moveable member 21 moves to the left, the arm 12 pivots away from the logging tool 10 and the angle between the locking member 18 and the normal 26 decreases.
[0078] When the position of the moveable member 21 is as illustrated in any of FIGS. 3A to 3G , any force acting on the arms 12 as shown by arrow Y in FIG. 3G , which tends to urge the arm 12 to close (towards the logging tool), causes the moveable member 21 to slide to the right. The logging tool 10 would, therefore, not be stable at such a time.
[0079] When the angle has decreased to zero, as shown in FIG. 3H (which approximately corresponds to the FIG. 2 component positions), this signifies that the arm 12 is at its maximum opening and will not pivot further. In this configuration any compressive forces acting on the arms 12 will act longitudinally along the locking members 18 with the result that the compression will be resisted. The moveable member 21 is however not in contact with the stop member 22 and can continue to move to the left.
[0080] Movement of the moveable member 21 further to the left, after the arms 12 have reached their maximum opening, causes the locking member 18 to pass the normal 26 and lie on the opposite side of the normal 26 to its starting position. This configuration is shown in FIG. 3I . At this time any compressive force acting on the arms 12 drives the moveable member 21 further to the left.
[0081] Continued movement of the moveable member 21 in direction X finally brings it into contact with the stop member 22 which then inhibits further movement of the moveable member 21 to the left. In this position, any force that pushes on the arms 12 (e.g. Force Z in FIG. 3J ) cannot cause the moveable members 18 to pass the normal 26 in the opposite direction. In other words, the arms 12 will not compress back towards the logging tool 10 , and neither will the locking member 18 move to the right. Instead, the moveable member 21 is pressed against the stop member 22 and the arms 12 are locked in place.
[0082] As can be seen above, the engagement of the moveable member 21 and the locking members 18 , when the arms 12 are in the position as illustrated in FIGS. 3H and 3J , provides an axial force that locks the arms 12 . The mechanism of the invention may be restored to a configuration permitting compression of the arms 12 into the recess 13 by driving the moveable member 21 to the right (as referenced in FIGS. 3A to 3J ).
[0083] The person of skill in the art is aware of techniques for causing such movement of the moveable member 21 , which in turn draws the locking members 18 to pass the normal 26 in the opposite (i.e. return) direction. This brings the apparatus to one of the configurations illustrated in FIGS. 3A to 3G . Receipt of the arms 12 into the recess 13 is then possible, either as a result of compressive forces acting on the arms 12 from the exterior of the logging tool 10 or because of further, powered movement of the moveable member 21 to the right in the schematic figures.
[0084] Alternative embodiments of the invention include one or more cam and follower arrangements for effecting movement of one or more reaction members. In such an embodiment the reaction members, which do not have to be embodied as pivoting arms, may include the followers of the cam and follower arrangement.
[0085] An embodiment of the invention having a cam and follower arrangement will now be described with reference to FIGS. 4A to 4C .
[0086] In FIG. 4A , there is shown a logging tool or logging tool sub 30 that as is commonly the case has an elongate, hollow cylindrical body 31 . Reaction members 34 of the logging tool 31 as illustrated in FIG. 4A are in their extended positions.
[0087] The cam and follower arrangement can be seen in FIGS. 4B and 4C , after the logging tool 30 depicted in FIG. 4A is dissected along the cutting line a and a front portion of the tool 30 is removed.
[0088] Inside the cylindrical body 31 there is a rotatable shaft 32 that has fixedly mounted thereon, and rotationally drives a triangular element 33 with truncated corners defining three lobes that are separated from one another by the sides of the generally triangular shape of the element 33 . The lobs and sides together define a continuous cam surface extending about the periphery of the triangular element 33 . The element 33 need not be triangular, however, and can be in other forms and shapes.
[0089] In the illustrated embodiment, there are three reaction members 34 , the reaction members 34 being equiangularly spaced within the cylindrical body 31 . There are three corresponding perforations 36 in the cylindrical body 31 which allow the reaction members 34 as desired partially to protrude beyond the surface of the cylindrical body 31 and retract within it. The number of reaction members and perforations in the scope of the invention is not limited to three, but this is the preferred member as it provides for good stability of landing of the logging tool 30 .
[0090] Each reaction member 34 has an inner end that contacts the triangular element 33 , and an outer end that when the reaction members are retracted as shown in FIG. 4B lies flush with and forms part of the surface of the cylindrical body 31 . When the reaction members 34 are in the retracted position as shown in FIG. 4B , inner end of each reaction member 34 lies flush with the surface of the cylindrical body 31 ; and the bottom half of each reaction member 34 sits on a side of the triangular element 33 .
[0091] When the shaft 32 rotates, the triangular element 33 rotates and the sliding motion of the triangular element 33 is converted into an outward linear force that pushes the reaction members 34 to protrude beyond the cylindrical body 31 . The reaction members as a result attain their extended positions as shown in FIG. 4C . The inner end of each reaction member 34 no longer sits on a side edge of the triangular element 33 , and is instead abutted by a truncated corner lobe of the triangular element 33 .
[0092] The reaction members 34 will remain in their extended positions, with their outer ends protruding out of the surface of the cylindrical body 31 , as long as each truncated corner lobe of the triangular element 33 continues to support the inner end of each reaction member 34 . The reaction members 34 are hence locked in place.
[0093] The reaction members are spring-biased towards the retracted position of FIG. 4B . As a result when the triangular cam element 33 rotates further the inner (follower) ends of the reaction members 34 bear against the sides of the triangular profile of the element 33 . In consequence the reaction members 34 are able to retract under the influence of the spring biasing.
[0094] Various techniques for commanding movement of the rotation of the shaft 32 even when the logging tool/sub 30 is far downhole are known in the logging tool art.
[0095] Alternative embodiments of the invention include one or more rack and pinion arrangements for effecting movement of one or more reaction members.
[0096] An embodiment of the invention having a rack and pinion arrangement will now be described with reference to FIGS. 5A to 5C .
[0097] FIG. 5A shows a logging tool or logging tool sub 40 that as is commonly the case has an elongate, hollow cylindrical body 41 . The reaction members of the logging tool 41 as illustrated in FIG. 5A are in their extended positions.
[0098] The rack and pinion arrangement can be seen in FIGS. 5B and 5C , after the logging tool 40 depicted in FIG. 5A is dissected along the cutting linep and a front portion of the tool 40 is removed.
[0099] Centrally mounted inside the cylindrical body 41 is a rotatable shaft 42 with a toothed outer periphery 42 defining a pinion.
[0100] In the illustrated embodiment, there are two P-shaped reaction members 43 . The scope of the invention however includes more or fewer of reaction members 43 that could be of various shapes and forms.
[0101] There are two perforations 44 in the cylindrical body which correspond to the positions of the reaction members 43 and allow them to protrude beyond the surface of the cylindrical body 41 .
[0102] Each P-shaped reaction member 43 is made up of a curved upper portion 48 that lies flush with the surface of the cylindrical body 41 when the reaction member 43 is in a retracted position. Each reaction member 43 has a perpendicular straight limb 47 a side of which facing the shaft 42 comprises teeth 46 . The teeth 46 meshingly engage with the teeth of the rotatable shaft 42 . The aforesaid sides of the straight limbs 47 constitute rack members and lie facing one another on opposite sides of the shaft 42 . The arrangement of the reaction members means they are capable of protruding as described below on opposite sides of the cylindrical body 41 .
[0103] As a result of engagement between the pinion teeth of shaft 42 and the rack teeth 46 , clockwise rotational motion of the shaft 42 is converted to linear motion of the reaction members 43 whereby in the illustrated embodiment as depicted in FIG. 5C , the reaction members 43 move outwards in opposite directions away from each other.
[0104] FIG. 5C depicts the logging tool 40 when the reaction members 43 are in their extended positions. As long as the rack teeth 46 on the straight limb 47 engage with the teeth on the shaft (pinion) 42 , the reaction members 43 are locked in their extended positions.
[0105] Rotation of the shaft in the anticlockwise direction causes retraction of the reaction members 43 . When this is effected, the upper portions 48 move until they lie flush with the outer surface of the cylindrical body 41 . In this position, the free end of each straight limb 47 abuts the underside of the upper portion 48 of the other reaction member 43 . As a result, retraction of the reaction members 43 is limited to the position shown, and the reaction members 43 do not become recessed relative to the cylindrical body 43 .
[0106] The interior of the cylindrical body 43 is hollowed to permit such movement of the described components.
[0107] As mentioned above, several methods for commanding movement of the rotation of the shaft 42 even when the logging tool/sub 40 is far downhole are known in the logging tool art.
[0108] In the embodiment of FIGS. 5A to 5C , the reaction members 43 are aligned with each other lengthwise along the cylindrical body. This need not necessarily be the case however; and it is possible for the reaction members to be longitudinally spaced from one another along the cylindrical body 41 .
[0109] In the various embodiments described above, the reaction members, or at least their in-use free ends, may be constituted as dogs that may latch or otherwise engage with landing features.
[0110] Numerous means may be employed, within the scope of the invention, for causing the reaction members to extend transversely with respect to the elongate dimension of the logging tool or sub.
[0111] The listing or discussion of an apparently prior-published document in this specification should not necessarily be taken as an acknowledgement that the document is part of the state of the art or is common general knowledge.
[0112] Preferences and options for a given aspect, feature or parameter of the invention should, unless the context indicates otherwise, be regarded as having been disclosed in combination with any and all preferences and options for all other aspects, features and parameters of the invention.
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A logging tool or sub ( 10 ) for downhole use comprises an elongate logging tool body ( 11 ); one or more moveable reaction members; and a locking member for the reaction members. At least one arm ( 12 ) at a first location is pivotably secured to the body ( 11 ) to be extensible therefrom and compressible towards the body ( 11 ); and at a second location spaced from the first location is pivotably secured to a locking member ( 18 ); and a stop member ( 22 ) fixed or fixable relative to the body ( 11 ). The locking member ( 18 ) defines a moveable end ( 19 ) remote from the second location and moveable relative to the arm ( 12 ) between at least a first position in which force tending to compress the arm ( 12 ) towards the body ( 11 ) causes the end ( 19 ) to move away from the stop member ( 22 ), and a second position in which force tending to compress the arm ( 12 ) towards the body ( 11 ) causes the stop member ( 22 ) to resist movement of the locking member ( 19 ) thereby preventing compression of the arm ( 12 ) towards the body ( 11 ). Alternatively, one or more cam and follower arrangement or rack and pinion arrangement can be used.
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This application is a continuation of U.S. application Ser. No. 11/488,943, entitled “Delivery of Drug Esters Through an Inhalation Route,” filed Jul. 18, 2003, Rabinowitz and Zaffaroni, which is a continuation of U.S. Pat. No. 7,078,019, entitled “Delivery of Drug Esters Through an Inhalation Route,” filed Dec. 30, 2003, Rabinowitz and Zaffaroni, which is a continuation of U.S. Pat. No. 6,737,042 entitled “Delivery of Drug Esters Through an Inhalation Route,” filed May 13, 2002, Rabinowitz and Zaffaroni, which claims priority to U.S. provisional application Ser. No. 60/294,203 entitled “Thermal Vapor Delivery of Drugs,” filed May 24, 2001 and to U.S. provisional application Ser. No. 60/317,479 entitled “Aerosol Drug Delivery,” filed Sep. 5, 2001, all of which are hereby incorporated by reference in their entirety.
FIELD OF THE INVENTION
The present invention relates to the delivery of drug esters through an inhalation route. Specifically, it relates to aerosols containing drug esters that are used in inhalation therapy.
BACKGROUND OF THE INVENTION
There are a number of compounds containing acids and alcohols that are currently marketed as drugs. In certain circumstances, the presence of such functionality prevents effective drug delivery. This phenomenon could be due to a range of effects, including poor solubility and inadequate transcellular transport.
It is desirable to provide a new route of administration for drug acids and alcohols that rapidly produces peak plasma concentrations of the compounds. The provision of such a route is an object of the present invention.
SUMMARY OF THE INVENTION
The present invention relates to the delivery of drug esters through an inhalation route. Specifically, it relates to aerosols containing drug esters that are used in inhalation therapy.
In a composition aspect of the present invention, the aerosol comprises particles comprising at least 5 percent by weight of drug ester. Preferably, the drug ester has a decomposition index less than 0.15. More preferably, it has a decomposition index less than 0.10 or 0.05. Preferably, the particles comprise at least 10 percent by weight of drug ester. More preferably, the particles comprise at least 20 percent, 30 percent, 40 percent, 50 percent, 60 percent, 70 percent, 80 percent, 90 percent, 95 percent, 97 percent, 99 percent, 99.5 percent or 99.97 percent by weight of drug ester.
Typically, the drug ester is an ester of a drug from one of the following classes: antibiotics, anticonvulsants, antidepressants, antihistamines, antiparkinsonian drugs, drugs for migraine headaches, drugs for the treatment of alcoholism, muscle relaxants, anxiolytics, nonsteroidal anti-inflammatories, other analgesics and steroids.
Typically, where the drug ester is an ester of an antibiotic, it is selected from an ester of one of the following compounds: cefmetazole; cefazolin; cephalexin; cefoxitin; cephacetrile; cephaloglycin; cephaloridine; cephalosporins, such as cephalosporin c; cephalotin; cephamycins, such as cephamycin a, cephamycin b, and cephamycin c; cepharin; cephradine; ampicillin; amoxicillin; hetacillin; carfecillin; carindacillin; carbenicillin; amylpenicillin; azidocillin; benzylpenicillin; clometocillin; cloxacillin; cyclacillin; methicillin; nafcillin; 2-pentenylpenicillin; penicillins, such as penicillin n, penicillin o, penicillin s, and penicillin v; chlorobutin penicillin; dicloxacillin; diphenicillin; heptylpenicillin; and metampicillin.
Typically, where the drug ester is an ester of an anticonvulsant, it is selected from an ester of one of the following compounds: 4-amino-3-hydroxybutyric acid, ethanedisulfonate, gabapentin, and vigabatrin.
Typically, where the drug ester is an ester of an antidepressant, it is selected from an ester of one of the following compounds: tianeptine and S-adenosylmethionine.
Typically, where the drug ester is an ester of an antihistamine, it is an ester of fexofenadine.
Typically, where the drug ester is an ester of an antiparkinsonian drug, it is selected from an ester of one of the following compounds: apomorphine, baclofen, levodopa, carbidopa, and thioctate.
Typically, where the drug ester is an ester of a drug for migraine headaches, it is selected from an ester of one of the following compounds: aspirin, diclofenac, naproxen, tolfenamic acid, and valproate.
Typically, where the drug ester is an ester of a drug for the treatment of alcoholism, it is an ester of acamprosate.
Typically, where the drug ester is an ester of a muscle relaxant, it is an ester of baclofen.
Typically, where the drug ester is an ester of an anxiolytic, it is selected from an ester of one of the following compounds: chlorazepate, calcium N-carboamoylaspartate and chloral betaine.
Typically, where the drug ester is an ester of a nonsteroidal anti-inflammatory, it is selected from an ester of one of the following compounds: aceclofenac, alclofenac, alminoprofen, amfenac, aspirin, benoxaprofen, bermoprofen, bromfenac, bufexamac, butibufen, bucloxate, carprofen, cinchophen, cinmetacin, clidanac, clopriac, clometacin, diclofenac, diflunisal, etodolac, fenclozate, fenoprofen, flutiazin, flurbiprofen, ibuprofen, ibufenac, indomethacin, indoprofen, ketoprofen, ketorolac, loxoprofen, meclofenamate, naproxen, oxaprozin, pirprofen, prodolic acid, salsalate, sulindac, tofenamate, and tolmetin.
Typically, where the drug ester is an ester of an other analgesic, it is selected from an ester of one of the following compounds: bumadizon, clometacin, and clonixin.
Typically, where the drug ester is an ester of a steroid, it is selected from an ester of one of the following compounds: betamethasone, chloroprednisone, clocortolone, cortisone, desonide, dexamethasone, desoximetasone, difluprednate, estradiol, fludrocortisone, flumethasone, flunisolide, fluocortolone, fluprednisolone, hydrocortisone, meprednisone, methylprednisolone, paramethasone, prednisolone, prednisone, pregnan-3-alpha-ol-20-one, testosterone, and triamcinolone.
Typically, where the drug ester is an ester of a drug acid, the ester is selected from an ester of the following type: C 1 -C 6 straight chain substituted or unsubstituted alkyl ester, C 1 -C 6 branched chain substituted or unsubstituted alkyl ester, C 3 -C 6 substituted or unsubstituted cyclic alkyl ester, C 1 -C 6 substituted or unsubstituted alkenyl ester, C 1 -C 6 substituted or unsubstituted alkynyl ester, and substituted or unsubstituted aromatic ester.
Typically, where the drug ester is an ester of a drug alcohol, the ester is selected from an ester of the following type: C 1 -C 6 substituted or unsubstituted straight chain alkanoate, C 1 -C 6 substituted or unsubstituted branched chain alkanoate, C 1 -C 6 substituted or unsubstituted alkenoate, and C 1 -C 6 substituted or unsubstituted alkynoate.
Typically, the drug ester is selected from one of the following: ketoprofen methyl ester, ketoprofen ethyl ester, ketoprofen norcholine ester, ketorolac methyl ester, ketorolac ethyl ester, ketorolac norcholine ester, indomethacin methyl ester, indomethacin ethyl ester, indomethacine norcholine ester, and apomorphine diacetate.
Typically, the aerosol has a mass of at least 0.01 mg. Preferably, the aerosol has a mass of at least 0.05 mg. More preferably, the aerosol has a mass of at least 0.10 mg, 0.15 mg, 0.2 g or 0.25 mg.
Typically, the particles comprise less than 10 percent by weight of drug ester degradation products. Preferably, the particles comprise less than 5 percent by weight of drug ester degradation products. More preferably, the particles comprise less than 2.5, 1, 0.5, 0.1 or 0.03 percent by weight of drug ester degradation products.
Typically, the particles comprise less than 90 percent by weight of water. Preferably, the particles comprise less than 80 percent by weight of water. More preferably, the particles comprise less than 70 percent, 60 percent, 50 percent, 40 percent, 30 percent, 20 percent, 10 percent, or 5 percent by weight of water.
Typically, the aerosol has an inhalable aerosol drug ester mass density of between 0.1 mg/L and 100 mg/L. Preferably, the aerosol has an inhalable aerosol drug mass density of between 0.1 mg/L and 75 mg/L. More preferably, the aerosol has an inhalable aerosol drug mass density of between 0.1 mg/L and 50 mg/L.
Typically, the aerosol has an inhalable aerosol particle density greater than 10 6 particles/mL. Preferably, the aerosol has an inhalable aerosol particle density greater than 10 7 particles/mL or 10 8 particles/mL.
Typically, the aerosol particles have a mass median aerodynamic diameter of less than 5 microns. Preferably, the particles have a mass median aerodynamic diameter of less than 3 microns. More preferably, the particles have a mass median aerodynamic diameter of less than 2 or 1 micron(s).
Typically, the geometric standard deviation around the mass median aerodynamic diameter of the aerosol particles is less than 2. Preferably, the geometric standard deviation is less than 1.9. More preferably, the geometric standard deviation is less than 1.8, 1.7, 1.6 or 1.5.
Typically, the aerosol is formed by heating a composition containing drug ester to form a vapor and subsequently allowing the vapor to condense into an aerosol.
In a method aspect of the present invention, a drug ester is delivered to a mammal through an inhalation route. The method comprises: a) heating a composition, wherein the composition comprises at least 5 percent by weight of drug ester, to form a vapor; and, b) allowing the vapor to cool, thereby forming a condensation aerosol comprising particles, which is inhaled by the mammal. Preferably, the drug ester has a decomposition index less than 0.15. More preferably, it has a decomposition index less than 0.10 or 0.05. Preferably, the composition that is heated comprises at least 10 percent by weight of drug ester. More preferably, the composition comprises at least 20 percent, 30 percent, 40 percent, 50 percent, 60 percent, 70 percent, 80 percent, 90 percent, 95 percent, 97 percent, 99 percent, 99.5 percent, 99.9 percent or 99.97 percent by weight of drug ester.
Typically, the drug ester is an ester of a drug from one of the following classes: antibiotics, anticonvulsants, antidepressants, antihistamines, antiparkinsonian drugs, drugs for migraine headaches, drugs for the treatment of alcoholism, muscle relaxants, anxiolytics, nonsteroidal anti-inflammatories, other analgesics and steroids.
Typically, where the drug ester is an ester of an antibiotic, it is selected from an ester of one of the following compounds: cefmetazole; cefazolin; cephalexin; cefoxitin; cephacetrile; cephaloglycin; cephaloridine; cephalosporins, such as cephalosporin c; cephalotin; cephamycins, such as cephamycin a, cephamycin b, and cephamycin c; cepharin; cephradine; ampicillin; amoxicillin; hetacillin; carfecillin; carindacillin; carbenicillin; amylpenicillin; azidocillin; benzylpenicillin; clometocillin; cloxacillin; cyclacillin; methicillin; nafcillin; 2-pentenylpenicillin; penicillins, such as penicillin n, penicillin o, penicillin s, and penicillin v; chlorobutin penicillin; dicloxacillin; diphenicillin; heptylpenicillin; and metampicillin.
Typically, where the drug ester is an ester of an anticonvulsant, it is selected from an ester of one of the following compounds: 4-amino-3-hydroxybutyric acid, ethanedisulfonate, gabapentin, and vigabatrin.
Typically, where the drug ester is an ester of an antidepressant, it is selected from an ester of one of the following compounds: tianeptine and S-adenosylmethionine.
Typically, where the drug ester is an ester of an antihistamine, it is an ester of fexofenadine.
Typically, where the drug ester is an ester of an antiparkinsonian drug, it is selected from an ester of one of the following compounds: apomorphine, baclofen, levodopa, carbidopa, and thioctate.
Typically, where the drug ester is an ester of a drug for migraine headaches, it is selected from an ester of one of the following compounds: aspirin, diclofenac, naproxen, tolfenamic acid, and valproate.
Typically, where the drug ester is an ester of a drug for the treatment of alcoholism, it is an ester of acamprosate.
Typically, where the drug ester is an ester of a muscle relaxant, it is an ester of baclofen.
Typically, where the drug ester is an ester of an anxiolytic, it is selected from an ester of one of the following compounds: chlorazepate, calcium N-carboamoylaspartate and chloral betaine.
Typically, where the drug ester is an ester of a nonsteroidal anti-inflammatory, it is selected from an ester of one of the following compounds: aceclofenac, alclofenac, alminoprofen, amfenac, aspirin, benoxaprofen, bermoprofen, bromfenac, bufexamac, butibufen, bucloxate, carprofen, cinchophen, cinmetacin, clidanac, clopriac, clometacin, diclofenac, diflunisal, etodolac, fenclozate, fenoprofen, flutiazin, flurbiprofen, ibuprofen, ibufenac, indomethacin, indoprofen, ketoprofen, ketorolac, loxoprofen, meclofenamate, naproxen, oxaprozin, pirprofen, prodolic acid, salsalate, sulindac, tofenamate, and tolmetin.
Typically, where the drug ester is an ester of an other analgesic, it is selected from an ester of one of the following compounds: bumadizon, clometacin, and clonixin.
Typically, where the drug ester is an ester of a steroid, it is selected from an ester of one of the following compounds: betamethasone, chloroprednisone, clocortolone, cortisone, desonide, dexamethasone, desoximetasone, difluprednate, estradiol, fludrocortisone, flumethasone, flunisolide, fluocortolone, fluprednisolone, hydrocortisone, meprednisone, methylprednisolone, paramethasone, prednisolone, prednisone, pregnan-3-alpha-ol-20-one, testosterone, and triamcinolone.
Typically, where the drug ester is an ester of a drug acid, the ester is selected from an ester of the following type: C 1 -C 6 straight chain substituted or unsubstituted alkyl ester, C 1 -C 6 branched chain substituted or unsubstituted alkyl ester, C 3 -C 6 substituted or unsubstituted cyclic alkyl ester, C 1 -C 6 substituted or unsubstituted alkenyl ester, C 1 -C 6 substituted or unsubstituted alkynyl ester, and substituted or unsubstituted aromatic ester.
Typically, where the drug ester is an ester of a drug alcohol, the ester is selected from an ester of the following type: C 1 -C 6 substituted or unsubstituted straight chain alkanoate, C 1 -C 6 substituted or unsubstituted branched chain alkanoate, C 1 -C 6 substituted or unsubstituted alkenoate, and C 1 -C 6 substituted or unsubstituted alkynoate.
Typically, the drug ester is selected from one of the following: ketoprofen methyl ester, ketoprofen ethyl ester, ketoprofen norcholine ester, ketorolac methyl ester, ketorolac ethyl ester, ketorolac norcholine ester, indomethacin methyl ester, indomethacin ethyl ester, indomethacine norcholine ester, and apomorphine diacetate.
Typically, the particles comprise at least 5 percent by weight of drug ester. Preferably, the particles comprise at least 10 percent by weight of drug ester. More preferably, the particles comprise at least 20 percent, 30 percent, 40 percent, 50 percent, 60 percent, 70 percent, 80 percent, 90 percent, 95 percent, 97 percent, 99 percent, 99.5 percent, 99.9 percent or 99.97 percent by weight of drug ester.
Typically, the condensation aerosol has a mass of at least 0.01 mg. Preferably, the aerosol has a mass of at least 0.05 mg. More preferably, the aerosol has a mass of at least 0.10 mg, 0.15 mg, 0.2 g or 0.25 mg.
Typically, the particles comprise less than 10 percent by weight of drug ester degradation products. Preferably, the particles comprise less than 5 percent by weight of drug ester degradation products. More preferably, the particles comprise 2.5, 1, 0.5, 0.1 or 0.03 percent by weight of drug ester degradation products.
Typically, the particles comprise less than 90 percent by weight of water. Preferably, the particles comprise less than 80 percent by weight of water. More preferably, the particles comprise less than 70 percent, 60 percent, 50 percent, 40 percent, 30 percent, 20 percent, 10 percent, or 5 percent by weight of water.
Typically, the particles of the delivered condensation aerosol have a mass median aerodynamic diameter of less than 5 microns. Preferably, the particles have a mass median aerodynamic diameter of less than 3 microns. More preferably, the particles have a mass median aerodynamic diameter of less than 2 or 1 micron(s).
Typically, the geometric standard deviation around the mass median aerodynamic diameter of the aerosol particles is less than 2. Preferably, the geometric standard deviation is less than 1.9. More preferably, the geometric standard deviation is less than 1.8, 1.7, 1.6 or 1.5.
Typically, the delivered aerosol has an inhalable aerosol drug ester mass density of between 0.1 mg/L and 100 mg/L. Preferably, the aerosol has an inhalable aerosol drug mass density of between 0.1 mg/L and 75 mg/L. More preferably, the aerosol has an inhalable aerosol drug mass density of between 0.1 mg/L and 50 mg/L.
Typically, the delivered aerosol has an inhalable aerosol particle density greater than 10 6 particles/mL. Preferably, the aerosol has an inhalable aerosol particle density greater than 10 7 particles/mL or 10 8 particles/mL.
Typically, the rate of inhalable aerosol particle formation of the delivered condensation aerosol is greater than 10 8 particles per second. Preferably, the aerosol is formed at a rate greater than 10 9 inhalable particles per second. More preferably, the aerosol is formed at a rate greater than 10 10 inhalable particles per second.
Typically, the delivered condensation aerosol is formed at a rate greater than 0.5 mg/second. Preferably, the aerosol is formed at a rate greater than 0.75 mg/second. More preferably, the aerosol is formed at a rate greater than 1 mg/second, 1.5 mg/second or 2 mg/second.
Typically, between 0.1 mg and 100 mg of drug ester are delivered to the mammal in a single inspiration. Preferably, between 0.1 mg and 75 mg of drug ester are delivered to the mammal in a single inspiration. More preferably, between 0.1 mg and 50 mg of drug ester are delivered in a single inspiration.
Typically, the delivered condensation aerosol results in a peak plasma concentration of drug acid or drug alcohol in the mammal in less than 1 h. Preferably, the peak plasma concentration is reached in less than 0.5 h. More preferably, the peak plasma concentration is reached in less than 0.2, 0.1, 0.05, 0.02 or 0.01 h.
In a kit aspect of the present invention, a kit for delivering a drug ester through an inhalation route to a mammal is provided which comprises: a) a composition comprising at least 5 percent by weight of drug ester; and, b) a device that forms a drug ester aerosol from the composition, for inhalation by the mammal. Preferably, the composition comprises at least 20 percent, 30 percent, 40 percent, 50 percent, 60 percent, 70 percent, 80 percent, 90 percent, 95 percent, 97 percent, 99 percent, 99.5 percent, 99.9 percent or 99.97 percent by weight of drug ester.
Typically the drug ester has a decomposition index less than 0.15. More preferably, it has a decomposition index less than 0.10 or 0.05.
Typically, the device contained in the kit comprises: a) an element for heating the drug ester composition to form a vapor; b) an element allowing the vapor to cool to form an aerosol; and, c) an element permitting the mammal to inhale the aerosol.
BRIEF DESCRIPTION OF THE FIGURE
FIG. 1 shows a cross-sectional view of a device used to deliver drug ester aerosols to a mammal through an inhalation route.
DETAILED DESCRIPTION OF THE INVENTION
Definitions
“Aerodynamic diameter” of a given particle refers to the diameter of a spherical droplet with a density of 1 g/mL (the density of water) that has the same settling velocity as the given particle.
“Aerosol” refers to a suspension of solid or liquid particles in a gas.
“Aerosol drug ester mass density” refers to the mass of drug ester per unit volume of aerosol.
“Aerosol mass density” refers to the mass of particulate matter per unit volume of aerosol.
“Aerosol particle density” refers to the number of particles per unit volume of aerosol.
“Condensation aerosol” refers to an aerosol formed by vaporization of a substance followed by condensation of the substance into an aerosol.
“Decomposition index” refers to a number derived from an assay described in Example 8. The number is determined by subtracting the percent purity of the generated aerosol from 1.
“Drug” refers to any chemical compound that is used in the prevention, diagnosis, treatment, or cure of disease, for the relief of pain, or to control or improve any physiological or pathological disorder in humans or animals. Such compounds are oftentimes listed in the Physician's Desk Reference (Medical Economics Company, Inc. at Montvale, N.J., 56 th edition, 2002), which is herein incorporated by reference.
“Drug acid” refers to a drug containing a carboxylic acid moiety.
“Drug alcohol” refers to a drug containing a hydroxyl moiety.
“Drug Ester” refers to a drug acid or drug alcohol, where the carboxylic acid group or hydroxyl group has been chemically modified to form an ester. The drug acids and alcohols from which the esters are formed come from a variety of drug classes, including, without limitation, antibiotics, anticonvulsants, antidepressants, antihistamines, antiparkinsonian drugs, drugs for migraine headaches, drugs for the treatment of alcoholism, muscle relaxants, anxiolytics, nonsteroidal anti-inflammatories, other analgesics, and steroids.
Examples of antibiotics from which drug esters are formed include cefmetazole; cefazolin; cephalexin; cefoxitin; cephacetrile; cephaloglycin; cephaloridine; cephalosporins, such as cephalosporin c; cephalotin; cephamycins, such as cephamycin a, cephamycin b, and cephamycin c; cepharin; cephradine; ampicillin; amoxicillin; hetacillin; carfecillin; carindacillin; carbenicillin; amylpenicillin; azidocillin; benzylpenicillin; clometocillin; cloxacillin; cyclacillin; methicillin; nafcillin; 2-pentenylpenicillin; penicillins, such as penicillin n, penicillin o, penicillin s, and penicillin v; chlorobutin penicillin; dicloxacillin; diphenicillin; heptylpenicillin; and metampicillin.
Examples of anticonvulsants from which drug esters are formed include 4-amino-3-hydroxybutyric acid, ethanedisulfonate, gabapentin, and vigabatrin.
Examples of antidepressants from which drug esters are formed include tianeptine and S-adenosylmethionine.
Examples of antihistamines from which drug esters are formed include fexofenadine.
Examples of antiparkinsonian drugs from which drug esters are formed include apomorphine, baclofen, levodopa, carbidopa, and thioctate.
Examples of anxiolytics from which drug esters are formed include chlorazepate, calcium N-carboamoylaspartate and chloral betaine.
Examples of drugs for migraine headache from which drug esters are formed include aspirin, diclofenac, naproxen, tolfenamic acid, and valproate.
Examples of drugs for the treatment of alcoholism from which drug esters are formed include acamprosate.
Examples of muscle relaxants from which drug esters are formed include baclofen.
Examples of nonsteroidal anti-inflammatories from which drug esters are formed include aceclofenac, alclofenac, alminoprofen, amfenac, aspirin, benoxaprofen, bermoprofen, bromfenac, bufexamac, butibufen, bucloxate, carprofen, cinchophen, cinmetacin, clidanac, clopriac, clometacin, diclofenac, diflunisal, etodolac, fenclozate, fenoprofen, flutiazin, flurbiprofen, ibuprofen, ibufenac, indomethacin, indoprofen, ketoprofen, ketorolac, loxoprofen, meclofenamate, naproxen, oxaprozin, pirprofen, prodolic acid, salsalate, sulindac, tofenamate, and tolmetin.
Examples of other analgesics from which drug esters are formed include bumadizon, clometacin, and clonixin.
Examples of steroids from which drug esters are formed include betamethasone, chloroprednisone, clocortolone, cortisone, desonide, dexamethasone, desoximetasone, difluprednate, estradiol, fludrocortisone, flumethasone, flunisolide, fluocortolone, fluprednisolone, hydrocortisone, meprednisone, methylprednisolone, paramethasone, prednisolone, prednisone, pregnan-3-alpha-ol-20-one, testosterone, and triamcinolone.
Examples of drug esters formed from drug acids include C 1 -C 6 straight chain substituted or unsubstituted alkyl esters, C 1 -C 6 branched chain substituted or unsubstituted alkyl esters, C 3 -C 6 substituted or unsubstituted cyclic alkyl esters, C 1 -C 6 substituted or unsubstituted alkenyl esters, C 1 -C 6 substituted or unsubstituted alkynyl esters, and substituted or unsubstituted aromatic esters. C 1 -C 6 straight chain unsubstituted alkyl esters include, for example, methyl ester, ethyl ester and propyl ester. C 1 -C 6 straight chain substituted alkyl esters include, for example, 2-(dimethylamino)-ethyl ester (—CH 2 CH 2 N(CH 3 ) 2 ). C 1 -C 6 branched chain unsubstituted alkyl esters include, for example, isopropyl ester and isobutyl ester. C 1 -C 6 branched chain substituted alkyl esters include, for example, 2-(dimethylamino)-isopropyl ester (—CH(CH 3 )CH 2 N(CH 3 ) 2 ). C 3 -C 6 unsubstituted cyclic alkyl esters include, for example, cyclopropyl and cyclohexyl ester. C 3 -C 6 substituted cyclic alkyl esters include, for example, 2-(dimethylamino)-cyclopropyl ester. C 1 -C 6 unsubstituted alkenyl esters include, for example, 2-butenyl ester (—CH 2 CHCHCH 3 ). C 1 -C 6 substituted alkenyl esters include, for example, 4-(dimethylamino)-2-butenyl ester (—CH 2 CHCHCH 2 N(CH 3 ) 2 ). C 1 -C 6 unsubstituted alkynyl esters include, for example, 2-butynyl ester (—CH 2 CCCH 3 ). C 1 -C 6 substituted alkynyl esters include, for example, 4-(dimethylamino)-2-butynyl ester (—CH 2 CCCH 2 N(CH 3 ) 2 ). Unsubstituted aromatic esters include, for example, phenyl ester and naphthyl ester. Substituted aromatic esters include, for example, 4-(dimethylamino)phenyl ester.
Examples of drug esters formed from drug alcohols include C 1 -C 6 substituted or unsubstituted straight chain alkanoates, C 1 -C 6 substituted or unsubstituted branched chain alkanoates, C 1 -C 6 substituted or unsubstituted alkenoates, and C 1 -C 6 substituted or unsubstituted alkynoates. C 1 -C 6 unsubstituted straight chain alkanoates include, for example, methanoate (—C(O)H), ethanoate (—C(O)CH 3 ) and propanoate (—C(O)CH 2 CH 3 ). C 1 -C 6 substituted straight chain alkanoates include, for example, 2-(phenyl)-ethanoate (—C(O)CH 2 Ph). C 1 -C 6 unsubstituted branched chain alkanoates include, for example, isobutanoate (—C(O)CH(CH 3 ) 2 ). C 1 -C 6 substituted branched chain alkanoates include, for example, 3-(phenyl)-isobutanoate (—C(O)CH(CH 3 )CH 2 Ph). C 1 -C 6 unsubstituted alkenoates include, for example, 2-butenoate (—C(O)CHCHCH 3 ). C 1 -C 6 substituted alkenoates include, for example, 4-(phenyl)-2-butenoate (—C(O)CHCHCH 2 Ph). C 1 -C 6 unsubstituted alkynoates include, for example, 2-butynoate (—C(O)CCCH 3 ). C 1 -C 6 substituted alkynoates include, for example, 4-(phenyl)-2-butynoate.
Examples of other drug esters are found in U.S. Pat. No. 5,607,691 to Hale et al. and U.S. Pat. No. 5,622,944 to Hale et al. These patents are herein incorporated by reference.
“Drug ester degradation product” refers to a compound resulting from a chemical modification of the drug ester. The modification, for example, can be the result of a thermally or photochemically induced reaction. Such reactions include, without limitation, oxidation and hydrolysis.
“Inhalable aerosol drug ester mass density” refers to the aerosol drug ester mass density produced by an inhalation device and delivered into a typical patient tidal volume.
“Inhalable aerosol mass density” refers to the aerosol mass density produced by an inhalation device and delivered into a typical patient tidal volume.
“Inhalable aerosol particle density” refers to the aerosol particle density of particles of size between 100 nm and 5 microns produced by an inhalation device and delivered into a typical patient tidal volume.
“Mass median aerodynamic diameter” or “MMAD” of an aerosol refers to the aerodynamic diameter for which half the particulate mass of the aerosol is contributed by particles with an aerodynamic diameter larger than the MMAD and half by particles with an aerodynamic diameter smaller than the MMAD.
“Norcholine ester” refers to an ester where the portion attached to the ester oxygen is —CH 2 CH 2 N(CH 3 ) 2 .
“Rate of aerosol formation” refers to the mass of aerosolized particulate matter produced by an inhalation device per unit time.
“Rate of inhalable aerosol particle formation” refers to the number of particles of size between 100 nm and 5 microns produced by an inhalation device per unit time.
“Rate of drug ester aerosol formation” refers to the mass of aerosolized, drug ester produced by an inhalation device per unit time.
“Settling velocity” refers to the terminal velocity of an aerosol particle undergoing gravitational settling in air.
“Substituted” alkyl, alkenyl, alkynyl or aryl refers to the replacement of one or more hydrogen atoms on the moiety (e.g., alkyl) with another group. Such groups include, without limitation, the following: halo, amino, alkylamino, dialkylamino, hydroxyl, cyano, nitro and phenyl.
“Typical patient tidal volume” refers to 1 L for an adult patient and 15 mL/kg for a pediatric patient.
“Vapor” refers to a gas, and “vapor phase” refers to a gas phase. The term “thermal vapor” refers to a vapor phase, aerosol, or mixture of aerosol-vapor phases, formed preferably by heating.
Formation of Drug Esters from Drug Acids or Drug Alcohols
Formation of drug esters from drug acids is typically accomplished by reacting the acid, or an activated derivative (e.g., acid chloride or mixed anhydride) with an appropriate alcohol under conditions well known to those of skill in the art. See, for example, Streitweiser, A., Jr. and Heathcock, C. H. (1981) Introduction to Organic Chemistry , Macmillan Publishing Col., Inc., New York. Conversely, formation of drug esters from drug alcohols is typically accomplished by reacting the alcohol with an appropriate activated acid derivative (e.g., ClC(O)CH 3 ). See Id.
Formation of Drug Ester Containing Aerosols
Any suitable method is used to form the aerosols of the present invention. A preferred method, however, involves heating a composition comprising a drug ester to form a vapor, followed by cooling of the vapor such that it condenses to provide a drug ester comprising aerosol (condensation aerosol). The composition is heated in one of two forms: as pure active compound (i.e., pure drug ester); or, as a mixture of active compound and a pharmaceutically acceptable excipient.
Pharmaceutically acceptable excipients may be volatile or nonvolatile. Volatile excipients, when heated, are concurrently volatilized, aerosolized and inhaled with drug ester. Classes of such excipients are known in the art and include, without limitation, gaseous, supercritical fluid, liquid and solid solvents. The following is a list of exemplary carriers within the classes: water; terpenes, such as menthol; alcohols, such as ethanol, propylene glycol, glycerol and other similar alcohols; dimethylformamide; dimethylacetamide; wax; supercritical carbon dioxide; dry ice; and mixtures thereof.
Solid supports on which the composition is heated are of a variety of shapes. Examples of such shapes include, without limitation, cylinders of less than 1.0 mm in diameter, boxes of less than 1.0 mm thickness and virtually any shape permeated by small (e.g., less than 1.0 mm-sized) pores. Preferably, solid supports provide a large surface to volume ratio (e.g., greater than 100 per meter) and a large surface to mass ratio (e.g., greater than 1 cm 2 per gram).
A solid support of one shape can also be transformed into another shape with different properties. For example, a flat sheet of 0.25 mm thickness has a surface to volume ratio of approximately 8,000 per meter. Rolling the sheet into a hollow cylinder of 1 cm diameter produces a support that retains the high surface to mass ratio of the original sheet but has a lower surface to volume ratio (about 400 per meter).
A number of different materials are used to construct the solid supports. Classes of such materials include, without limitation, metals, inorganic materials, carbonaceous materials and polymers. The following are examples of the material classes: aluminum, silver, gold, stainless steel, copper and tungsten; silica, glass, silicon and alumina; graphite, porous carbons, carbon yarns and carbon felts; polytetrafluoroethylene and polyethylene glycol. Combinations of materials and coated variants of materials are used as well.
Where aluminum is used as a solid support, aluminum foil is a suitable material. Examples of silica, alumina and silicon based materials include amphorous silica S-5631 (Sigma, St. Louis, Mo.), BCR171 (an alumina of defined surface area greater than 2 m 2 /g from Aldrich, St. Louis, Mo.) and a silicon wafer as used in the semiconductor industry. Carbon yarns and felts are available from American Kynol, Inc., New York, N.Y. Chromatography resins such as octadecycl silane chemically bonded to porous silica are exemplary coated variants of silica.
The heating of the drug ester compositions is performed using any suitable method. Examples of methods by which heat can be generated include the following: passage of current through an electrical resistance element; absorption of electromagnetic radiation, such as microwave or laser light; and, exothermic chemical reactions, such as exothermic solvation, hydration of pyrophoric materials and oxidation of combustible materials.
Delivery of Drug Ester Containing Aerosols
Drug ester containing aerosols of the present invention are delivered to a mammal using an inhalation device. Where the aerosol is a condensation aerosol, the device has at least three elements: an element for heating a drug ester containing composition to form a vapor; an element allowing the vapor to cool, thereby providing a condensation aerosol; and, an element permitting the mammal to inhale the aerosol. Various suitable heating methods are described above. The element that allows cooling is, in it simplest form, an inert passageway linking the heating means to the inhalation means. The element permitting inhalation is an aerosol exit portal that forms a connection between the cooling element and the mammal's respiratory system.
One device used to deliver the drug ester containing aerosol is described in reference to FIG. 1 . Delivery device 100 has a proximal end 102 and a distal end 104 , a heating module 106 , a power source 108 , and a mouthpiece 110 . A drug ester composition is deposited on a surface 112 of heating module 106 . Upon activation of a user activated switch 114 , power source 108 initiates heating of heating module 106 (e.g, through ignition of combustible fuel or passage of current through a resistive heating element). The drug ester composition volatilizes due to the heating of heating module 106 and condenses to form a condensation aerosol prior to reaching the mouthpiece 110 at the proximal end of the device 102 . Air flow traveling from the device distal end 104 to the mouthpiece 110 carries the condensation aerosol to the mouthpiece 110 , where it is inhaled by the mammal.
Devices, if desired, contain a variety of components to facilitate the delivery of drug ester containing aerosols. For instance, the device may include any component known in the art to control the timing of drug aerosolization relative to inhalation (e.g., breath-actuation), to provide feedback to patients on the rate and/or volume of inhalation, to prevent excessive use (i.e., “lock-out” feature), to prevent use by unauthorized individuals, and/or to record dosing histories.
In Vivo Hydrolysis of Drug Esters
After delivery of a drug ester aerosol to the lung of an animal, the ester moiety is typically hydrolyzed to provide the corresponding drug acid or drug alcohol, which produces a desired therapeutic effect. Where the ester reacts with water at ˜pH 7.4 at an appreciable rate, hydrolysis is chemically mediated. For other esters, hydrolysis is enzymatically mediated through the action of enzymes endogenous to the animal.
Dosage of Drug Ester Containing Aerosols
A typical dosage of a drug ester aerosol is either administered as a single inhalation or as a series of inhalations taken within an hour or less (dosage equals sum of inhaled amounts). Where the drug ester is administered as a series of inhalations, a different amount may be delivered in each inhalation. The dosage amount of drug ester in aerosol form is generally no greater than twice the standard dose of the drug acid or drug alcohol given orally.
One can determine the appropriate dose of drug ester containing aerosols to treat a particular condition using methods such as animal experiments and a dose-finding (Phase I/II) clinical trial. One animal experiment involves measuring plasma concentrations of drug acid or drug alcohol in an animal after its exposure to the aerosol. Mammals such as dogs or primates are typically used in such studies, since their respiratory systems are similar to that of a human. Initial dose levels for testing in humans is generally less than or equal to the dose in the mammal model that resulted in plasma drug levels associated with a therapeutic effect in humans. Dose escalation in humans is then performed, until either an optimal therapeutic response is obtained or a dose-limiting toxicity is encountered.
Analysis of Drug Ester Containing Aerosols
Purity of a drug ester containing aerosol is determined using a number of methods, examples of which are described in Sekine et al., Journal of Forensic Science 32:1271-1280 (1987) and Martin et al., Journal of Analytic Toxicology 13:158-162 (1989). One method involves forming the aerosol in a device through which a gas flow (e.g., air flow) is maintained, generally at a rate between 0.4 and 60 L/min. The gas flow carries the aerosol into one or more traps. After isolation from the trap, the aerosol is subjected to an analytical technique, such as gas or liquid chromatography, that permits a determination of composition purity.
A variety of different traps are used for aerosol collection. The following list contains examples of such traps: filters; glass wool; impingers; solvent traps, such as dry ice-cooled ethanol, methanol, acetone and dichloromethane traps at various pH values; syringes that sample the aerosol; empty, low-pressure (e.g., vacuum) containers into which the aerosol is drawn; and, empty containers that fully surround and enclose the aerosol generating device. Where a solid such as glass wool is used, it is typically extracted with a solvent such as ethanol. The solvent extract is subjected to analysis rather than the solid (i.e., glass wool) itself. Where a syringe or container is used, the container is similarly extracted with a solvent.
The gas or liquid chromatograph discussed above contains a detection system (i.e., detector). Such detection systems are well known in the art and include, for example, flame ionization, photon absorption and mass spectrometry detectors. An advantage of a mass spectrometry detector is that it can be used to determine the structure of drug ester degradation products.
Particle size distribution of a drug ester containing aerosol is determined using any suitable method in the art (e.g., cascade impaction). An Andersen Eight Stage Non-viable Cascade Impactor (Andersen Instruments, Smyrna, Ga.) linked to a furnace tube by a mock throat (USP throat, Andersen Instruments, Smyrna, Ga.) is one system used for cascade impaction studies.
Inhalable aerosol mass density is determined, for example, by delivering a drug-containing aerosol into a confined chamber via an inhalation device and measuring the mass collected in the chamber. Typically, the aerosol is drawn into the chamber by having a pressure gradient between the device and the chamber, wherein the chamber is at lower pressure than the device. The volume of the chamber should approximate the tidal volume of an inhaling patient.
Inhalable aerosol drug ester mass density is determined, for example, by delivering a drug ester-containing aerosol into a confined chamber via an inhalation device and measuring the amount of non-degraded drug ester collected in the chamber. Typically, the aerosol is drawn into the chamber by having a pressure gradient between the device and the chamber, wherein the chamber is at lower pressure than the device. The volume of the chamber should approximate the tidal volume of an inhaling patient. The amount of non-degraded drug ester collected in the chamber is determined by extracting the chamber, conducting chromatographic analysis of the extract and comparing the results of the chromatographic analysis to those of a standard containing known amounts of drug ester.
Inhalable aerosol particle density is determined, for example, by delivering aerosol phase drug ester into a confined chamber via an inhalation device and measuring the number of particles of given size collected in the chamber. The number of particles of a given size may be directly measured based on the light-scattering properties of the particles. Alternatively, the number of particles of a given size is determined by measuring the mass of particles within the given size range and calculating the number of particles based on the mass as follows: Total number of particles=Sum (from size range 1 to size range N) of number of particles in each size range. Number of particles in a given size range=Mass in the size range/Mass of a typical particle in the size range. Mass of a typical particle in a given size range=π*D 3 φ/6, where D is a typical particle diameter in the size range (generally, the mean boundary MMADs defining the size range) in microns, φ is the particle density (in g/mL) and mass is given in units of picograms (g −12 ).
Rate of inhalable aerosol particle formation is determined, for example, by delivering aerosol phase drug ester into a confined chamber via an inhalation device. The delivery is for a set period of time (e.g., 3 s), and the number of particles of a given size collected in the chamber is determined as outlined above. The rate of particle formation is equal to the number of 100 nm to 5 micron particles collected divided by the duration of the collection time.
Rate of aerosol formation is determined, for example, by delivering aerosol phase drug ester into a confined chamber via an inhalation device. The delivery is for a set period of time (e.g., 3 s), and the mass of particulate matter collected is determined by weighing the confined chamber before and after the delivery of the particulate matter. The rate of aerosol formation is equal to the increase in mass in the chamber divided by the duration of the collection time. Alternatively, where a change in mass of the delivery device or component thereof can only occur through release of the aerosol phase particulate matter, the mass of particulate matter may be equated with the mass lost from the device or component during the delivery of the aerosol. In this case, the rate of aerosol formation is equal to the decrease in mass of the device or component during the delivery event divided by the duration of the delivery event.
Rate of drug ester aerosol formation is determined, for example, by delivering a drug ester containing aerosol into a confined chamber via an inhalation device over a set period of time (e.g., 3 s). Where the aerosol is pure drug ester, the amount of drug collected in the chamber is measured as described above. The rate of drug ester aerosol formation is equal to the amount of drug ester aerosol collected in the chamber divided by the duration of the collection time. Where the drug ester containing aerosol comprises a pharmaceutically acceptable excipient, multiplying the rate of aerosol formation by the percentage of drug ester in the aerosol provides the rate of drug aerosol formation.
Utility of Drug Ester Containing Aerosols
The drug ester containing aerosols of the present invention are typically used for the same indication as the corresponding drug acid or drug alcohol. For instance, a drug ester of baclofen would be used to treat parkinsons disease and a drug ester of fexofenadine would be used to treat allergy symptoms.
The following examples are meant to illustrate, rather than limit, the present invention.
Drug acids or drug alcohols are typically commercially available from Sigma, obtained in tablet form from a pharmacy and extracted, or synthesized using well known methods in the art.
EXAMPLE 1
General Procedures for Esterifying a Drug Acid
Drug acid (10 mmol) is dissolved in 90 mL of dichloromethane. To the solution is added 1 drop of dimethylformamide and 13 mmol of oxalyl chloride. The resulting mixture is allowed to stir 30 min. The mixture is concentrated to dryness on a rotary evaporator to provide a residue, to which 50 mL of an alcohol (e.g., methanol) is added. The alcoholic solution is concentrated to dryness to afford the desired drug ester.
Drug acid (6 mmol) is dissolved in 60 mL of dichloromethane. To the solution is added 1 drop of dimethylformamide and 9 mmol of oxalyl chloride. The resulting mixture is allowed to stir 1 h. The mixture is concentrated to dryness on a rotary evaporator to provide a residue, to which 47 mmol of an alcohol (e.g., HOCH 2 CH 2 N(CH 3 ) 2 ) in 20 mL dichloromethane is added. The reaction mixture is diluted with 60 mL dichloromethane and subjected to a series of washings: 50 mL saturated aqueous NaCl followed by 50 mL saturated aqueous NaHCO 3 and 2×50 mL saturated aqueous NaCl. The dichloromethane extract is dried over Na 2 SO 4 , filtered, and concentrated on a rotary evaporator to provide the desired drug ester.
EXAMPLE 2
General Procedure for Esterifying a Drug Alcohol
Drug alcohol (5 mmol) is dissolved in 50 mL of dichloromethane. To the solution is added 5.5 mmol Hünig's base and 10 mmol acetyl chloride. The reaction mixture is allowed to stir at room temperature for 1 hour. The mixture is washed with 50 mL saturated aqueous NaHCO 3 followed by 50 mL saturated aqueous NaCl. The dichloromethane extract is dried over Na 2 SO 4 , filtered, and concentrated on a rotary evaporator to provide the desired drug ester.
EXAMPLE 3
Procedure for Diesterifying Apomorphine
Apomorphine HCl.½H 2 O (300 mg) was suspended in 600 μL of acetic acid. The suspension was heated to 100° C. and then cooled to 50° C. Acetyl chloride (1 mL) was added to the suspension, which was heated at 40° C. for 3 h. The reaction mixture was allowed to cool to room temperature. Dichloromethane (1-2 mL) was added and the mixture was allowed to stir overnight. The reaction mixture was diluted with dichloromethane, and the solvent was removed on a rotary evaporator. Toluene (10 mL) was added to the residue and subsequently removed on a rotary evaporator. The toluene addition/removal was repeated. The resulting solid residue was triturated with ether, providing 430 mg of a solid (mp 158-160° C.).
A portion of the solid (230 mg) was suspended in 50 mL of dichloromethane. The suspension was washed with saturated aqueous NaHCO 3 . The dichloromethane layer was dried over Na 2 SO 4 , filtered and concentrated on a rotary evaporator to provide 190 mg of the desired free base (mp ˜110° C.).
EXAMPLE 4
Procedure for Synthesis of 2-(N,N-Dimethylamino)Ethyl Ester of Ketorolac
Ketorolac (255 mg), triethylamine (101 mg) and 2-(dimethylamino)ethanol (HOCH 2 CH 2 N(CH 3 ) 2 , 380 mg) were added to 2 mL dichloromethane. The mixture was cooled to −25° C. to −20° C. for 15 min. BOP (464 mg) was added, and the reaction mixture was gradually allowed to warm to room temperature. See Kim, M. H. and Patel, D. V. (1994) Tet. Lett. 35: 5603-5606. The reaction mixture was diluted with 60 mL of dichloromethane and washed sequentially with saturated aqueous NaCl, saturated aquesous NaHCO 3 and then saturated aqueous NaCl. The dichloromethane extract was dried over Na 2 SO 4 , filtered, and concentrated on a rotary evaporator to provide 390 mg of the desired material.
EXAMPLE 5
General Procedure for Volatilizing Compounds from Halogen Bulb
A solution of drug in approximately 120 μL dichloromethane is coated on a 3.5 cm×7.5 cm piece of aluminum foil (precleaned with acetone). The dichloromethane is allowed to evaporate. The coated foil is wrapped around a 300 watt halogen tube (Feit Electric Company, Pico Rivera, Calif.), which is inserted into a glass tube sealed at one end with a rubber stopper. Running 60 V of alternating current (driven by line power controlled by a variac) through the bulb for 5-12 s or 90 V for 2.5-3.5 s affords thermal vapor (including aerosol), which is collected on the glass tube walls. (When desired, the system is flushed through with argon prior to volatilization.) Reverse-phase HPLC analysis with detection by absorption of 225 nm light is used to determine the purity of the aerosol.
Table 1, which follows, provides data from drugs volatilized using the above-recited general procedure.
TABLE 1
AEROSOL
COMPOUND
AEROSOL PURITY
MASS
Indomethacin Methyl Ester
99%
1.44 mg
Indomethacin Ethyl Ester
>99%
3.09 mg
Indomethacin Norcholine Ester
100%
2.94 mg
Ketoprofen Methyl Ester
99%
4.4 mg
Ketoprofen Ethyl Ester
99.65%
4.11 mg
Ketoprofen Norcholine Ester
100%
2.6 mg
Ketorolac Methyl Ester
100%
3.17 mg
Ketorolac Ethyl Ester
>99%
5.19 mg
Ketorolac Norcholine Ester
100%
1.64 mg
Apomorphine Diacetate-HCl
94%
1.65 mg
Apomorphine Diacetate
96.9%
2.03 mg
EXAMPLE 6
General Procedure for Hydrolysis Studies of Drug Esters
Drug ester (20 μL, 10 mM acetonitrile) is added to 1 mL PBS solution (pH 7.5) at room temperature. At intermittent time points, an aliquot of the resulting mixture is injected into an HPLC to obtain the ratio of drug ester to drug acid or drug alcohol. An Arrhenius plot of the data provides a t 1/2 for hydrolysis. Table 2 below provides t 1/2 values for a variety of compounds.
TABLE 2
COMPOUND
t 1/2
Ketoprofen Methyl Ester
>48
h
Ketoprofen Ethyl Ester
>48
h
Ketoprofen Norcholine Ester
315
min.
Ketorolac Methyl Ester
>48
h
Ketorolac Ethyl Ester
>48
h
Ketorolac Norcholine Ester
14
min
Indomethacin Methyl Ester
>48
h
Indomethacin Ethyl Ester
>48
h
Indomethacin Norcholine Ester
315
min.
Apomorphine Diacetate
>48
h
EXAMPLE 7
General Procedure for Human Serum Hydrolysis Studies of Drug Esters
Human serum (2.34 mL) is placed in a test tube. To the serum is added 260 μL of a 10 mM solution of drug ester in acetonitrile. The tube is placed in a 37° C. incubator, and at various time points a 500 μL aliquot is removed. The aliquot is mixed with 500 μL methanol, and the mixture is vortex mixed and centrifuged. A sample of the supernatant is analyzed by HPLC obtain the ratio of drug ester to drug acid or drug alcohol. An Arrhenius plot of the data provides a t 1/2 for hydrolysis. Table 3 below provides t 1/2 values for a variety of compounds.
TABLE 3
COMPOUND
t 1/2
Ketoprofen Methyl Ester
144
min
Ketoprofen Ethyl Ester
224
min
Ketoprofen Norcholine
37
s
Ester
Ketorolac Ethyl Ester
90
min
Ketorolac Norcholine Ester
13
s
Indomethacin Methyl Ester
>48
h
Indomethacin Ethyl Ester
>48
h
Indomethacin Norcholine
23
min
Ester
Apomorphine Diacetate
76.2
s
EXAMPLE 8
General Procedure for Screening Drug Esters for Aerosolization Preferability
Drug ester (1 mg) is dissolved or suspended in a minimal amount of a suitable solvent (e.g., dichloromethane or methanol). The solution or suspension is pipetted onto the middle portion of a 3 cm by 3 cm piece of aluminum foil. The coated foil is wrapped around the end of a 1½ cm diameter vial and secured with parafilm. A hot plate is preheated to approximately 300° C., and the vial is placed on it foil side down. The vial is left on the hotplate for 10 s after volatilization or decomposition has begun. After removal from the hotplate, the vial is allowed to cool to room temperature. The foil is removed, and the vial is extracted with dichloromethane followed by saturated aqueous NaHCO 3 . The organic and aqueous extracts are shaken together, separated, and the organic extract is dried over Na 2 SO 4 . An aliquot of the organic solution is removed and injected into a reverse-phase HPLC with detection by absorption of 225 nm light. A drug ester is preferred for aerosolization where the purity of the drug ester aerosol isolated by this method is greater than 85%. Such a drug ester has a decomposition index less than 0.15. The decomposition index is arrived at by subtracting the percent purity (i.e., 0.85) from 1.
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The present invention relates to the delivery of drug esters through an inhalation route. Specifically, it relates to aerosols containing drug esters that are used in inhalation therapy. In a method aspect of the present invention, a drug ester is delivered to a patient through an inhalation route. The method comprises: a) heating a composition, wherein the composition comprises a drug ester, to form a vapor; and, b) allowing the vapor to cool, thereby forming a condensation aerosol comprising particles with less than 5% drug ester degradation product. In a kit aspect of the present invention, a kit for delivering a drug ester through an inhalation route is provided which comprises: a) a thin coating of a drug ester composition and b) a device for dispensing said thin coating as a condensation aerosol.
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RELATED APPLICATIONS
[0001] This application claims priority of Provisional Application S/No. 60/335,662 filed on Oct. 23, 2001.
FIELD OF THE INVENTION
[0002] The present invention relates to the field of building design; more specifically, it relates to emergency stairwells for multistory building.
BACKGROUND OF THE INVENTION
[0003] Most multistory buildings are provided with emergency stairwells to provide quick evacuation of the building in the event of an emergency such as a fire and as alternative evacuation routes to elevators.
[0004] In conventional emergency stairwell design, the widths of the stairwell remains constant from the uppermost floors serviced by the emergency stairwell to the lowermost floors serviced by the emergency stairwell. This design is predicated on the assumption that persons entering the emergency stairwell from lower floors will have reached the lowermost egress from the emergency stairwell before persons entering the emergency stairwell from upper floors reach the lower floors.
[0005] One problem with this assumption is that in high buildings, people get tired and their rate of descent slows down. As persons from upper floors overtake these now, slower moving persons, congestion builds up slowing egress still more. A similar slowdown can occur when more vigorous or able persons overtake less vigorous or able persons.
[0006] Another problem with conventional emergency stairwells, especially in very high buildings is, other than floor numbering, there is no stimulus that indicates the progress is being made to an eventual egress. Going down floor after floor can become claustrophobic and induce panic in the evacuees.
[0007] Providing more emergency stairwells does not address these problems, and building uniformly wider emergency staircases, while addressing some of the problems is wasteful of expensive floor space.
[0008] Therefore there is a need for an improved emergency stairwell that reduces or eliminates buildup of congestion on sections of the stairwell servicing lower floors, provides some more than a textual indication that progress toward an egress is being made and does not consume unacceptable amounts of floor space.
SUMMARY OF THE INVENTION
[0009] A first aspect of the present invention is an emergency stairwell for a building having multiple floors comprising: at least one landing associated with each the floor, each landing increasing in width in at least one horizontal direction from an uppermost landing of an upper floor to a lowermost landing of a lower floor; and at least one set of stairs extending between adjacent pairs of landings.
[0010] A second aspect of the present invention is an emergency stairwell for a building having multiple floors comprising: a plurality of stairwell sections, each section comprising: a set of landings, one landing of each set of landings associated with one the floor, and at least one set of stairs extending between adjacent pairs of landings, all landings within a stairwell section having the same width in at least one horizontal direction; and each stairwell section and associated landings within that stairwell section increasing in width in at least one horizontal direction from an uppermost stairwell section associated with a group of adjacent upper floors to a lowermost stairwell section associated with a group of adjacent lower floors.
BRIEF DESCRIPTION OF DRAWINGS
[0011] The features of the invention are set forth in the appended claims. The invention itself, however, will be best understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings, wherein:
[0012] [0012]FIG. 1 is cross-sectional view of multistory building having an emergency stairwell according to a first embodiment of the present invention;
[0013] [0013]FIG. 2 is top view of a section of the emergency stairwell of FIG. 1;
[0014] [0014]FIG. 3 is a top view of a section of an alternative emergency stairwell according to the present invention;
[0015] [0015]FIG. 4A is a top view of a section of an emergency stairwell according to a second embodiment of the present invention;
[0016] [0016]FIG. 4B is a side view of a portion of the emergency stairwell according the second embodiment of the present invention; and
[0017] [0017]FIG. 5 is cross-sectional view of multistory building having an emergency stairwell according a third embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0018] The description of the embodiments of the present invention is given above for the understanding of the present invention. It will be understood that the invention is not limited to the particular embodiments described herein, but is capable of various modifications, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore it is intended that the following claims cover all such modifications and changes as fall within the true spirit and scope of the invention.
[0019] [0019]FIG. 1 is cross-sectional view of multistory building having an emergency stairwell according to a first embodiment of the present invention. In FIG. 1, a multistory building 100 includes a multiplicity of floors 105 A through 105 L, floor 105 A being the lowest floor, closet to a ground level 110 , and floor 105 L being the highest floor, immediately under a roof 115 . Building 100 also includes an emergency stairwell 120 . One or more fire doors 125 on each floor 105 of building 100 provide access to the emergency stairwell.
[0020] In one example, fire doors 125 provide access to upper landings 130 . Upper stair sets 135 connect upper landings 130 to lower landings 140 . Lower landings 140 are connected to the upper landings 130 of the immediately lower floor 105 by lower stair sets 145 .
[0021] Emergency stairwell 120 has two widths, a first width within the plane of the paper and a second width perpendicular to the plane of the paper. Only the first width is illustrated in FIG. 1. Emergency stairwell 120 has a first width “W 1 ” at the lowest floor (in the present example, floor 105 A) and a first width “W 2 ” at the highest floor (in the present example, floor 105 L.) “W 1 ” is greater than “W 2 .” The first (and second) width of emergency stairwell 120 increases by a fixed amount from floor to floor such that the lower of any two adjacent floors is wider than the upper floor. Upper and lower landings 130 and 140 get wider in both first and second widths, while upper and lower stair sets 135 and 145 only get wider only in the second width, progressively from upper to lower floors. The number of steps (and hence the length) in upper and lower stair sets 135 and 145 remains constant from floor to floor as long as the height of each floor is the same. Or more precisely, the ratio of the total horizontal run to total vertical drop of stair sets 135 and 145 remains constant from floor to floor as long as the height of each floor is the same.
[0022] The progressively wider width(s) of emergency stairwell 120 from the upper floors to the lower floors of building 100 works to prevent backup of evacuees in the stairwell on upper floors due to congestion on the stairwell on lower floors by providing increasing area and hence carrying capacity of the stairwell. Further, the progressively wider width(s) of emergency stairwell 120 from the upper floors to the lower floors of building 100 provides visual stimulus that indicates that progress is being made to an eventual egress.
[0023] [0023]FIG. 2 is top view of a section of the emergency stairwell of FIG. 1. In FIG. 2, emergency stairwell 120 , has a first width “A 1 ” and a second width “A 2 ” in a portion 150 of the emergency stairwell corresponding to an upper floor (for example floor 105 L of FIG. 1) and a first width “A 3 ” and second width “A 4 ” in a portion 155 of the emergency stairwell corresponding to a lower floor (for example, floor 105 K of FIG. 1.) In one example “A 1 ”=“A 2 ,” “A 3 ”=“A 4 ” and “A 1 ”>“A 3 ” by an amount Δ. Upper landing 130 has a first width “A 5 ” and a second width “A 2 .” Lower landing 140 has a first width “A 6 ” and a second width “A 4 .” “A 6 ” is greater than “A 5 ” by amount Δ. Upper stair set 135 has width “A 7 ” and a length “A 8 .” Lower stair set 145 has width “A 9 ” and a length “A 8 .” In one example, “A 9 ”=“A 7 ”+Δ/2. Hence, stairwell 120 increases in first and second widths by an amount Δ from the portion of the stairwell immediately above.
[0024] [0024]FIG. 3 is a top view of a section of an alternative emergency stairwell according to the present invention. One difference between the emergency stairwell of FIG. 2 and that illustrated in FIG. 3 is the number of landings. In FIG. 3, an emergency stairwell 160 , has a first width “B 1 ” and a second width “B 2 ” in a portion 165 of the emergency stairwell corresponding to an upper floor (for example floor 105 L of FIG. 1.) An upper landing 165 has a first width “B 3 ” and a second width “B 4 .” A next lower, first intermediate landing 170 has a first width “B 5 ” and a second width “B 4 .” First intermediate landing 170 is connected to upper landing 165 by first stair set 175 . First stair set 175 has a first width “B 6 ” and a second width “B 4 .” First intermediate landing 170 is also connected to a second intermediate landing 180 by a second stair set 185 . Second stair set 185 has a first width “B 5 ” and a second width “B 6 .” Second intermediate landing 180 has a first width “B 7 ” and a second width “B 8 .” Second intermediate landing 180 resides in a portion 190 of emergency stairwell 160 corresponding to the transition from an upper floor (for example 105 L of FIG. 1) and a lower floor (for example, floor 105 K of FIG. 1.) Second intermediate landing 180 is connected to a third intermediate landing 195 by a third stair set 200 . Third stair set 200 has a first width “B 6 ” and a second width “B 8 .” Third intermediate landing 195 has a first width “B 7 ” and a second width “B 8 .” Third intermediate landing 195 is connected to a lower floor landing (not shown) by a fourth stair set 205 . Fourth stair set 205 has a first width “B 7 ” and a second width “B 6 .”
[0025] In one example “B 1 ”=“B 2 , “B 3 ”=“B 4 ”=“B 5 ”=“B 6 ,” “B 7 ”=“B 8 ,” “B 7 ”=“B 5 ”+Δ/2 and “B 8 ”=“B 4 ”=Δ/2. Δ is the incremental increase in size of emergency stairwell 160 from floor to floor progressing from upper to lower floors.
[0026] [0026]FIG. 4A is a top view of a section of an emergency stairwell according to a second embodiment of the present invention. In FIG. 4A, a portion 210 of an emergency stairwell 215 includes a floor landing 220 and a multiplicity of steps 225 A through 225 G between a cone shaped outer wall 230 and a cylindrical inner wall 235 . Inner wall 235 may include a void 240 as illustrated or may be solid. Each step 225 A through 225 G has a width “C 1 ” through “C 7 ” respectively. Since outer wall 230 is cone shaped each step is wider than the immediately upper step by an amount Δ′ but narrower than the immediately lower step by the same amount Δ′. This is more clearly illustrated in FIG. 4 B. Therefore, “C 2 ”=“C 1 ”+Δ′, “C 3 ”=“C 2 ”+Δ′, “C 4 ”=“C 3 ”+Δ′, “C 5 ”=“C 4 ”+Δ′, “C 6 ”=“C 5 ”+Δ′ and “C 7 ”=“C 6 ”+Δ′.
[0027] [0027]FIG. 4B is a side view of a portion of the emergency stairwell according the second embodiment of the present invention. In FIG. 4B, emergency stairwell 215 is shown passing through an upper floor 245 and a lower floor 255 . Access to stairwell 215 from upper floor 245 is through fire door 250 onto landing 220 . Access to stairwell 215 from lower floor 255 is through fire door 260 onto a floor landing 265 . Floor landing 220 on floor 245 is “C 1 ” wide, while step 225 D is “C 4 ” wide and floor landing 265 is “C 8 ” wide, where “C 8 ”=“C 7 ”+Δ′.
[0028] [0028]FIGS. 4C and 4D illustrate respectively stepped and ramped options for the second embodiment of the present invention. FIG. 4C is a cross section through a portion of several steps, 225 A through 225 C of emergency stairwell 215 . Optionally, steps may be replaced with a ramp as illustrated in FIG. 4D. FIG. 4D is a cross section through a portion of ramp 270 , which replaces steps, 225 A through 225 C illustrated in FIG. 4C of emergency stairwell 215 .
[0029] [0029]FIG. 5 is cross-sectional view of multistory building having an emergency stairwell according a third embodiment of the present invention. In FIG. 5, a multistory building 3100 includes a multiplicity of floors 305 A through 305 L, floor 305 A being the lowest floor, closet to a ground level 310 , and floor 305 L being the highest floor, immediately under a roof 315 . Building 300 also includes an emergency stairwell 320 . One or more fire doors 325 on each floor 305 of building 300 provide access to the emergency stairwell.
[0030] In one example, fire doors 325 provide access to upper landings 330 . Upper stair sets 335 connect upper landings 330 to lower landings 340 . Lower landings 340 are connected to the upper landings 330 of the immediately lower floor 305 by lower stair sets 345 .
[0031] Emergency stairwell 320 has two widths, a first width within the plane of the paper and a second width perpendicular to the plane of the paper. Only the first width is illustrated in FIG. 51. Emergency stairwell 320 has a first section 350 A having a width “W 3 ” comprised of the three lowest floors (in the present example, floors 305 A, 305 B and 305 C), a second section 350 B having a width “W 4 ” comprised of the next three higher (in the present example, floors 305 D, 305 E and 305 F), a third section 350 C having a width “W 5 ” comprised of the next three higher (in the present example, floors 305 G, 305 H and 305 I) and a fourth section 350 D having a width “W 6 ” comprised of the highest three floors (in the present example, floors 305 J, 305 K and 305 L.) The number of floors 305 within in each section 350 of emergency stairwell 320 may be a number other than three, for example from two half the number of floors in the building or more. The number of floors 305 within each section 350 of emergency stairwell 320 need not be the same. The first (and second) widths of emergency stairwell 320 increases by a fixed amount for example Δ″ from section to section such that the lower of any two adjacent sections is wider than the upper section. Thus “W 5 ”=“W 6 ”+Δ”, “W 4 ”=“W 5 ”+Δ″ and “W 3 ”=“W 3 ”+Δ″. Upper and lower landings 330 and 340 get wider in both first and second widths, while upper and lower stair sets 335 and 345 only get wider only in the second width, progressively from upper to lower sections. The number of steps (and hence the length) in upper and lower stair sets 335 and 345 remains constant from floor to floor as long as the height of each floor is the same.
[0032] The values for all widths “W 1 ” through “W 6 ”, “A 1 ” through “A 9 ”, “B 1 ” through “B 6 ”, “C 1 ” through “C 7 ” and “D 1 ” through “D 2 ” and all delta's Δ, Δ′ and Δ″ are primarily functions of the number of occupants of each floor and the number of floors in the building.
[0033] The description of the embodiments of the present invention is given above for the understanding of the present invention. It will be understood that the invention is not limited to the particular embodiments described herein, but is capable of various modifications, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. For example, more than one emergency stairwell according to the present invention may be present within the same building. Further, a single emergency stairwell of the present invention need not run through all floors of the building, but only through a contiguous subset of the floors. Still further, the various embodiments of the emergency stairwell of the present invention herein described, may be used in combination with one another within the same building. Finally, one or more emergency stairwells according to the present invention may be used in combination with one or more emergency stairwells of conventional design.
[0034] The description of the embodiments of the present invention is given above for the understanding of the present invention. It will be understood that the invention is not limited to the particular embodiments described herein, but is capable of various modifications, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, it is intended that the following claims cover all such modifications and changes as fall within the true spirit and scope of the invention.
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An emergency stairwell for a building having multiple floors comprising: at least one landing associated with each the floor, each landing increasing in width in at least one horizontal direction from an uppermost landing of an upper floor to a lowermost landing of a lower floor; and at least one set of stairs extending between adjacent pairs of landings.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to corrosion-resistant cast iron and can be used in the metallurgy and foundry practice for the production of cast iron articles for use in chemical and petrochemical engineering.
It is common knowledge that segregation of main alloying components, which takes place during solidification of cast iron, results in a macroheterogeneous and microheterogeneous distribution of the alloying components. The segregation occurs even in the austenitic grain.
When such a cast iron is cooled down to a certain temperature depending on the macrodistribution and microdistribution of the alloying components the austenitic metal base partially dissociates to form martensite or bainite. The austenitic metal base dissociation causes a volume expansion of the cast iron, which in turn results in the increase of size of the resultant articles. This unwanted effect (formation of products of the austenite dissociation at the grain boundaries, and in the regions adjacent the graphite inclusions) affects to a great extent the corrosion resistance of the cast iron.
Therefore, apart from a high corrosion resistance, the corrosion-resistant cast iron should have a high resistance to its volume expansion. Hereinafter the term "expansion resistance" is used to mean a stability of the austenitic metal base, when the latter is subjected to a one-time or repeated cooling in the range of subzero temperatures, and the absence of phase transformations which lead to irreversible changes in the size of castings, and affect the corrosion resistance of the cast iron.
2. Prior Art
There is known a corrosion-resistant cast iron (USSR Author's Certificate No. 451,784) comprising, by mass %:
______________________________________carbon 2.6 to 3.6manganese 0.3 to 1.5copper 0.5 to 9.0magnesium 0.02 to 0.12yttrium 0.01 to 0.10tin 0.01 to 0.10silicon 2.0 to 3.4nickel 14 to 17chromium 0.01 to 1.8calcium 0.01 to 0.15rare-earth metals 0.01 to 0.10aluminium 0.005 to 0.3iron balance______________________________________
Apart from high physical and mechanical properties this cast iron features resistance to corrosion when exposed to such corrosive media as ammonia liquor, sodium hydroxide, trisodium phosphate, perhydrol, calcium hydroxide, and also methanol, benzene, and carbon tetrachloride.
The prior art cast iron, however, shows a low corrosion resistance in petroleum saturated with hydrogen sulfide, and in the water having an elevated content of cations of iodine and bromine (iodine-bromide water).
Furthermore, said cast iron shows expansion resistance only at a temperature higher than -45° C., which limits its application in the chemical and petrochemical engineering.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a corrosion-resistant cast iron which due to its high corrosion resistance and expansion resistance permits the field of its application in the chemical and petrochemical industries to be widened and the operating properties of the articles made therefrom to be improved.
The object of the invention is achieved by that a known in the art corrosion-resistant cast iron comprising carbon, silicon, manganese, nickel, chromium, copper, aluminium, magnesium, calcium, rare-earth metals, and iron, according to the invention further includes barium, tantalum, and niobium, with said cast iron ingredients taken in the following amounts, by mass %:
______________________________________carbon 2.5 to 3.2silicon 0.95 to 2.4manganese 0.8 to 4.0nickel 12.0 to 18.0chromium 0.5 to 2.0copper 4.0 to 8.0aluminium 0.01 to 0.3magnesium 0.005 to 0.07calcium 0.01 to 0.10rare-earth metals 0.001 to 0.08barium 0.001 to 0.1tantalum 0.003 to 0.02niobium 0.005 to 0.3iron balance______________________________________
The composition of the proposed cast iron provides for a high stability thereof in a petroleum saturated with hydrogen sulfide and in iodine-bromide water. The proposed corrosion-resistant cast iron features a resistance to expansion at temperatures below zero to -60° C., which permits the proposed corrosion-resistant cast iron to be widely used in chemical and petrochemical engineering, and the operating properties of the articles manufactured from this cast iron to be improved.
The presence of tantalum in the composition of the proposed cast iron in said amount makes it possible to raise the degree of dispersion of carbide inclusions and to thereby decrease microsegregation of alloying components which segregation affects corrosion resistance of the cast iron. The tantalum content in the cast iron is determined taking account of the following factors: if its content is higher than the recommended upper limit, the tantalum will favour solidification of the cast iron according to a metastable system, and in case said content is lower than the recommended lower limit, the tantalum will not have its effect at all.
The use of niobium in the composition of the proposed cast iron in said amount decreases segregation of nickel and copper in regions adjacent to the carbide inclusions, provides for a higher ductility of the cast iron, and favours cleaning of the grain boundaries from nitride inclusions.
The niobium content in the proposed cast iron depends on the rate of cooling and on the extent of its degassing because of its increased affinity for nitrogen. At elevated rates of cooling, with the niobium content being below the recommended lower limit, the niobium does not decrease segregation of nickel and copper. The upper limit of the niobium content in the cast iron is determined by the degree of degassing of a modified cast iron and by its influence on the mechanical properties of the cast iron at low rates of cooling the resultant casting.
Barium is an efficient modifying agent and at the same time an active graphitizing element in the modified cast iron. The cast iron modified by barium used in a recommended amount is less prone to chilling and overcooling.
It is recommended that the corrosion-resistant cast iron also include cobalt, with said cast iron ingredients taken in the following amounts, by mass %:
______________________________________carbon 2.5 to 3.2silicon 0.95 to 1.9manganese 0.8 to 4.0nickel 12.0 to 18.0chromium 0.5 to 2.0copper 4.0 to 8.0cobalt 0.05 to 0.3aluminium 0.01 to 0.3magnesium 0.01 to 0.07calcium 0.01 to 0.10rare-earth metals 0.01 to 0.08barium 0.001 to 0.10tantalum 0.003 to 0.02niobium 0.005 to 0.2iron balance______________________________________
The presence of cobalt in the cast iron in said amounts decreases segregation of manganese and copper in the regions adjacent the grain boundaries, thereby favouring their more uniform distribution in the iron austenitic base, and decreasing the probability of the local austenite dissociation in the castings at low rates of cooling. This cast iron manifests a resistance to expansion at subzero temperature as low as -80° C.
It is expedient that the corrosion-resistant cast iron also include titanium, with said cast iron ingredients taken in the following amounts, by mass %:
______________________________________carbon 2.5 to 3.2silicon 0.95 to 2.4manganese 0.8 to 4.0nickel 12.0 to 18.0chromium 0.5 to 2.0copper 4.0 to 8.0aluminium 0.01 to 0.3magnesium 0.005 to 0.05calcium 0.01 to 0.05rare-earth metals 0.001 to 0.02barium 0.001 to 0.1tantalum 0.003 to 0.02niobium 0.01 to 0.3cobalt 0.05 to 0.3titanium 0.05 to 0.5iron balance______________________________________
Said corrosion-resistant cast iron features a high corrosion resistance in iodine-bromide water, petroleum saturated with hydrogen sulfide, expansion resistance at temperatures below zero to -80° C., and perfect casting properties.
DETAILED DESCRIPTION OF THE INVENTION
A corrosion-resistant cast iron of the invention was produced by alloying and modifying a melt of starting cast iron in a ladle with the use of various additions.
The starting cast iron is produced in electric furnaces. In this particular case the cast iron was smelted in an induction furnace. The smelting was carried out with the use of conventional charge materials, namely, nickel, cobalt, and a carburizing agent. After reaching a temperature of from 1530° to 1580° C., the melt thus produced is poured into a ladle containing a modifying agent preliminarily placed thereinto, said modifying agent containing magnesium, rare-earth metals, calcium, barium, and other elements. The quantity of the modifying agent is selected depending on the quality of the starting materials, cross-section of the castings to be produced and on the requirements placed thereupon. Pouring the cast iron melt was done at a temperature of from 1350° to 1450° C.
The cast iron thus produced was analyzed for chemical composition and tested for mechanical properties, corrosion resistance, and casting properties.
The samples for mechanical testing were cut from V-shaped pieces 370 mm long, 140 mm high, and which were 50 mm wide at the top and 30 mm wide at the bottom. The tests were conducted by conventional methods.
The samples both for corrosion tests in various corrosive liquids and for determining the microstructure of the cast iron, were cut from cast plates 10 mm thick, 50 mm wide, and 250 mm long.
The samples for corrosion test in the petroleum saturated with hydrogen sulfide after their having been degreased, dried and weighed were immersed in the petroleum through which was continuously passed hydrogen sulfide. The temperature of the petroleum was 100° C., and the test lasted 100 hours. After the completion of the test the samples were carefully cleaned from rust, washed, dried, and weighed. The rate of loss in material weight was determined by the loss in weight of the samples in a unit time related to a unit of the surface area.
The corrosion tests of the cast iron in other corrosive media were conducted in a similar way except for that said corrosive media had a room temperature. The duration of the corrosion test in iodine-bromide water was 500 hours including 120 hours for which said corrosive medium had a temperature of 80° C.±5° C.
The casting properties of the cast iron were determined by fluidity and by the volume of the contraction cavities and pores.
The fluidity of the cast iron in a liquid state was determined by that quartz pipes 3±0.1 mm in dia, having a negative pressure of 210±5 mm Hg, were filled with the cast iron being tested, whereafter the fluidity of said cast iron was determined by measuring the length of the pipe portion filled with the cast iron at various temperatures thereof.
The volume of the contraction cavities and pores was determined by applying conventional methods.
The invention will now be explained in greater detail with reference to embodiments thereof.
EXAMPLE 1
Corrosion-resistant cast iron of the invention was produced in the following manner.
First, a starting cast iron was produced in an induction furnace, which cast iron had the following composition (by mass %):
______________________________________ carbon 2.90 silicon 1.02 manganese 1.40 nickel 15.1 copper 7.5 chromium 1.30 sulphur 0.039 phosphorus 0.03 aluminium 0.10 niobium 0.11 tantalum 0.01 iron balance______________________________________
The starting cast iron of the above composition was then treated in a ladle at a temperature of 1500° C. by a modifying agent taken in an amount of 2% by weight of the melt.
The modifying agent was composed of the following elements, (by mass %):
______________________________________calcium 8.6magnesium 5.8aluminium 1.7rare-earth metals 5.3silicon 46.0barium 3.1iron balance______________________________________
Pouring the cast iron thus produced was done at a temperature of 1350° C. The thus produced corrosion-resistant cast iron had the following composition (by mass %):
______________________________________carbon 2.82silicon 1.59manganese 1.31nickel 15.06copper 7.5chromium 1.31calcium 0.06phosphorus 0.03sulphur 0.016aluminium 0.12niobium 0.11tantalum 0.01barium 0.04magnesium 0.04rare-earth metals 0.05iron balance______________________________________
The resultant corrosion-resistant cast iron was analyzed for chemical composition, and tested for mechanical properties and corrosion resistance.
For the purpose of comparison there also was tested the prior art corrosion-resistant cast iron produced according to USSR Author's Certificate No 451,784, which had the following composition (by mass %):
______________________________________carbon 2.62silicon 3.37nickel 16.81manganese 0.3chromium 1.74copper 9.0aluminium 0.26tin 0.10calcium 0.12magnesium 0.06rare-earth metals 0.03yttrium 0.04iron balance______________________________________
Table 1 below contains in a tabulated form the results of a microstructural analysis of the proposed corrosion-resistant cast iron and a corrosion-resistant cast iron produced in accordance with USSR Author's Certificate No 451,784.
TABLE 1______________________________________ Corrosion-resis- tant cast iron Corrosion-resistant produced accord- cast iron produced ing to USSR as described in CertificateCharacteristics Example 1 No. 451,784______________________________________Graphiteshape globular globularquantity, % 5 3Metal baseaustenite, % 88 77carbides, % 7 20______________________________________
As can be seen from Table 1, solidification of the cast iron, whose chemical composition corresponds to USSR Author's Certificate No 451,784, is accompanied by the formation of a considerable quantity of carbide inclusions.
Results of the tests for corrosion resistance in various corrosive media of the proposed corrosion-resistant cast iron and of the prior art corrosion-resistant cast iron produced in accordance with USSR Author's Certificate No 451,784, are given in a tabulated form in Table 2.
Iodine-bromide water used in the tests for corrosion resistance and given in the tables, contained 0.04 g/l of J, and 0.31 g/l of Br, with the total salt content being 176.5 g/l.
TABLE 2______________________________________ Rate of weight loss, g/m.sup.2 per hour Con- Corrosion-resis- Corrosion-resistant centra- tant cast iron cast iron produc- tion produced as de- ed according to vol- scribed in USSR Author's Cer-Medium ume % Example 1 tificate No. 451,7841 2 3 4______________________________________Sulphuric 75 0.069 0.081acidSodium hy- 40 0.0028 0.004droxideSlaked lime 20 0.0049 0.005Ammonia 10 0.010 0.012Trisodium 3 0.0101 0.020phosphatePerhydrol -- 0.0143 0.023Methanol -- 0.0108 0.015Benzene -- 0.0098 0.011Carbon tetra- -- 0.0095 0.015chlorideIodine-bro- -- 0.0650 0.116mide waterPetroleum -- 0.0059 0.0645saturated withhydrogensulfide______________________________________
Thus, as may be seen from the above table, the proposed corrosion-resistant cast iron has a higher corrosion resistance when exposed to corrosive media, and in particular to a petroleum saturated with hydrogen sulfide, and iodine-bromide water.
Table 3 shows in a tabulated form the results of the physical and mechanical tests to which were subjected both the proposed corrosion-resistant cast iron and the prior art corrosion-resistant cast iron produced in accordance with USSR Author's Certificate No 451,784.
TABLE 3______________________________________ Prior art cast Proposed cast iron rion (USSR Author's produced as described CertificateCharacteristics in Example 1 No. 451,784)______________________________________Tensile strength, 425.3 402MPaElongation, % 16 13Impact strength, 50 27.5J/cm.sup.2Hardness, HB 133 167______________________________________
As will be seen from Table 3 the proposed corrosion-resistant cast iron features a higher strength and ductility.
EXAMPLE 2
A corrosion-resistant cast iron of the invention had the following composition (by mass %):
______________________________________carbon 3.19silicon 1.9nickel 18.0manganese 2.01chromium 2.0copper 8.0barium 0.10niobium 0.20tantalum 0.02aluminium 0.3calcium 0.1magnesium 0.07rare-earth metals 0.08iron balance______________________________________
The test results of the above corrosion-resistant cast iron are given below.
______________________________________The results of microstructural analysis:characteristics of the graphiteshape globularquantity 5%characteristics of the metal baseaustenite 87%carbides 8%Corrosion resistance properties:(a) in a petroleum saturated with hydrogen sulfide; test duration, hrs 100 rate of weight loss, g/m.sup.2 per hr 0.0125 depth of corrosion, mm per year 0.0132(b) in iodine-bromide water: test duration, hrs 500 rate of weight loss, g/m.sup.2 per hr 0.0619 depth of corrosion, mm per year 0.0724Physical and mechanical properties:tensile strength, MPa 441,5elongation, % 10.0impact strength, J/cm.sup.2 34.3hardness, HB 165______________________________________
EXAMPLE 3
A corrosion-resistant cast iron of the invention had the following composition (by mass %):
______________________________________carbon 2.50silicon 0.95nickel 15.0manganese 0.8chromium 0.5copper 4.0barium 0.01niobium 0.005tantalum 0.003aluminium 0.01calcium 0.01magnesium 0.01rare-earth metals 0.01iron balance______________________________________
The test results of the above corrosion-resistant cast iron are given below.
______________________________________The results of microstructural analysis:characteristics of the graphite:shape globularquantity 7%characteristics of the metal base:austenite, % 88carbides, % 5Corrosion-resistance properties:(a) in a petroleum saturated with hydrogen sulfide: test duration, hrs 100 rate of weight loss, g/m.sup.2 per hr 0.0069 depth of corrosion, mm per year 0.0081(b) in iodine-bromide water: test duration, hrs 500 rate of weight loss, g/m.sup.2 per hr 0.0746 depth of corrosion, mm per year 0.0872Physical and mechanical properties:tensile strength, MPa 372.8elongation, % 20impact strength, J/cm.sup.2 54.9hardness, HB 127______________________________________
EXAMPLE 4
Corrosion-resistant cast iron of the invention had the following composition (by mass %):
______________________________________carbon 2.8silicon 1.5nickel 16.2manganese 1.4chromium 1.2copper 5.9barium 0.05niobium 0.1tantalum 0.01aluminium 0.15calcium 0.04magnesium 0.03rare-earth metals 0.03cobalt 0.14iron balance______________________________________
The tests results of the above corrosion-resistant cast iron are given below.
______________________________________Microstructural analysis:characteristics the graphiteshape globularquantity, % 5characteristics of the metal base:austenite, % 91carbides, % 4Corrosion resistance properties:(a) in a petroleum saturated with hydrogen sulfide; test duration, hrs 100 rate of weight loss, g/m.sup.2 per hr 0.0046 depth of corrosion, mm per year 0.0054(b) in iodine-bromide water: test duration, hrs 500 rate of weight loss, g/m.sup.2 per hr 0.0280 depth of corrosion, mm per year 0.0336Physical and mechanical properties:tensile strength, MPa 487.4elongation, % 19.2impact strength, J/cm.sup.2 55.0hardness, HB 127.0______________________________________
EXAMPLE 5
A corrosion-resistant cast iron of the invention had the following composition (by mass %):
______________________________________carbon 2.8silicon 1.5nickel 16.2manganese 1.4chromium 1.2copper 5.9barium 0.02niobium 0.1tantalum 0.01aluminium 0.15calcium 0.02magnesium 0.02rare-earth metals 0.005cobalt 0.12titanium 0.17iron balance______________________________________
The test results of the above corrosion-resistant cast iron are given below.
______________________________________Microstructural analysis:characteristics of the graphite:shape vermicularquantity, % 8characteristics of the metal baseaustenite, % 89carbides, % 3Corrosion resistance properties:(a) in a petroleum saturated with hydrogen sulfide: test duration, hrs 100 rate of weight loss, g/m.sup.2 per hr 0.0054 depth of corrosion, mm per year 0.0063(b) in iodine-bromide water: test duration, hrs 500 rate of weight loss, g/m.sup.2 per hr 0.0374 depth of corrosion, mm per year 0.0437Physical and mechanical properties:tensile strength, MPa 265.4elongation, % 6impact strength, J/cm.sup.2 21.5hardness, HB 127Casting properties:fluidity at the casting temperature of 3201350° C., mmfluidity at the casting temperature of 3001300° C., mmfluidity at the casting temperature of 2701200° C., mmtotal volume of the contraction cavities and 4.0pores, %shrinkage porosity 1.6%______________________________________
While particular embodiments of the invention have been shown and described, various modifications thereof will be apparent to those skilled in the art and therefore it is not intended that the invention be limited to the disclosed embodiments or to the details thereof and the departures may be made therefrom within the spirit and scope of the invention as defined in the claims.
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A corrosion-resistant cast iron comprises (by mass %):
______________________________________
carbon 2.5 to 3.2silicon 0.95 to 2.4manganese 0.8 to 4.0nickel 12.0 to 18.0chromium 0.5 to 2.0copper 4.0 to 8.0aluminium 0.01 to 0.3magnesium 0.005 to 0.07calcium 0.01 to 0.10rare-earth metals 0.001 to 0.08barium 0.001 to 0.1tantalum 0.003 to 0.02niobium 0.005 to 0.3iron balance______________________________________
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This is a division of application Ser. No. 410,057, filed Oct. 26, 1973, now U.S. Pat. No. 3,897,553 which is a division of application Ser. No. 184,225, filed Sept. 27, 1971, now U.S. Pat. No. 3,808,264.
BACKGROUND OF THE INVENTION
This invention relates to novel organotin compounds, a method for their preparation, pesticidal and herbicidal compositions containing said compounds, and to a method of combating pests and unwanted vegetation.
The desirability of controlling or eradicating insect pests and common disease-causing organisms is clearly accepted. Thus, compounds possessing insecticidal, acaricidal, bacteriostatic and fungicidal properties especially adapted to such control or eradication are or particular importance.
The necessity of controlling or eradicating unwanted plants, e.g., weeds from fields planted with growing crops, by means of chemical herbicides is also clearly accepted.. Such chemical control of undesirable plant growth is more efficient and less expensive than manual control. However, the chemical control of weeds in the presence of growing food crops has been somewhat hindered because of several factors. For example, many herbicides are unsuitable for use with food crops because of toxic residues remaining on the crops after application.
Certain organotin compounds have been previously disclosed for use as pesticides, herbicides, and the like; see the co-pending application of Peterson, entitled "Novel Organotin Compounds", Ser. No. 164,941, filed July 21, 1971 now U.S. Pat. No. 3,784,580. The preparation of certain organotin-sulfur compounds is described in the co-pending application of Peterson, entitled "Preparation of Organotin Compounds", Ser. No. 158,528, filed June 30, 1971 now U.S. Pat. No. 3,794,670.
Many useful organotin compounds are relatively expensive and it is an object of this invention to provide novel, relatively inexpensive organotin compounds and a method for their preparation. A further object is to provide novel organotin-substituted sulfolene and sulfolane compounds which are useful as insecticides, acaricides, bacteriostats, fungicides and herbicides. Another object is to provide pesticidal compositions containing the novel organotin-substituted sulfolene and sulfolane compounds. A still further object is to provide novel compositions and methods effective for combating insects and other pests, such as weeds, and bacterial and fungal organisms. These and other objects are obtained by this invention as will be apparent from the following disclosure.
SUMMARY OF THE INVENTION
The novel organotin-substituted sulfolene and sulfolane compoounds of the present invention are of the formula: ##SPC2##
where each R is selected from the group consisting of alkyl of from 1 to about 14 carbon atoms (e.g., methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, amyl, iso-amyl, hexyl, n-octyl, n-dodecyl, n-tetradecyl); aryl (e.g., phenyl, naphthyl); substituted aryl (e.g., p-methoxyphenyl, p-tolyl, p-chlorophenyl, o-methoxyphenyl); and each R' is alkyl of from 1 to about 14 carbon atoms, aryl, or hydrogen.
In its process aspect, this invention comprises reacting an organotin amine compound of the formula: (R 3 Sn) x NR" 3 -x , wherein x is an integer from 1 to 3, R is as disclosed above, and each R" is selected from the group consisting of alkyl (C 1 to C 10 ) or hydrogen, with a sulfolene or sulfolane compound of the formula: ##SPC3##
wherein R' is as disclosed above, to yield the isomeric organotin-2-sulfolenes, organotin-3-sulfolenes and organotin-substituted sulfolanes of the type disclosed above, respectively.
The present invention also encompasses pesticidal compositions (a term which includes insecticides, herbicides, acaricides and the like) comprising one or more of the organotin-substituted sulfolene or sulfolane compounds disclosed herein and a carrier vehicle of the type hereinafter disclosed.
DETAILED DESCRIPTION OF THE INVENTION
The isomeric organotin-2-sulfolene and organotin-3-sulfolene compounds of this invention can be prepared by various methods. For example, 2-sulfolenes can be metalated by any of the common metalating agents (e.g., n-butyllithium) to provide the corresponding metalated sulfolene which can be subsequently reacted with a triorganotin halide. However, such processes require the use of extremely low reaction temperatures and expensive reagents and equipment.
In accordance with the process aspects of the present invention, the isomeric organotin sulfolene compounds of this invention are prepared by reacting 3-sulfolene compounds with an organotin amine compound according to the following gross scheme: ##SPC4##
wherein R, R' and R" are as hereinabove defined. Trialkyltin amines (C 1 -C 20 ) are preferred in this process; the tributyltin amines are especially preferred. The 2-sulfolene isomers can also be used in this process, but are not preferred in that they must first be prepared by base isomerization of the 3-sulfolene compound, thereby requiring an additional step. The organotin-substituted sulfolane compounds herein are prepared in like manner using an organotin amine and a sulfolane compound of the type disclosed above.
The organotin amine compounds used in the present process can be prepared by reacting the alkali metal salts of ammonia and primary and secondary amines with triorganotin halides, e.g., triorganotin fluorides, chlorides, bromides and iodides, which are commercially available. The alkali metal salts of primary and secondary amines and ammonia are themselves prepared by reacting said amines with the corresponding metals in the manner well-known to those skilled in the art. For example, ammonia will react with sodium to yield sodamide which, in turn, will react with a triorganotin halide to prepare the corresponding organotin amine. Dimethylamine will react with lithium metal in the presence of a conjugated diene such as butadiene to form lithium dimethylamide, which, in turn, reacts with a triorganotin halide to form the N,N-dimethylaminoorganotin compound. Alternatively, various amines can be metalated in standard fashion with, for example, organolithium compounds to provide the metal amine salts. In general terms, the preparation of the organotin amines useful in the preparation of the organotin sulfolene and sulfolane compounds of this invention is represented by the following reaction sequence:
R".sub.2 NH + C.sub.4 H.sub.9 M→R".sub.2 NM + C.sub.4 H.sub.10 or,
2R".sub.2 NH + 2M →2R".sub.2 NM + H.sub.2 then,
R".sub.2 NM + R.sub.3 SnX →R".sub.2 NSnR.sub.3 + MX,
wherein M is alkali metal, i.e., lithium, sodium, potassium, rubidium, and cesium; wherein R and R" are as defined above; and wherein X is a halogen, i.e., fluoride, chloride, bromide and iodide. It will be recognized that when primary amines, secondary amines and ammonia are used herein, organotin amines of the formula R 3 SnNR" 2 , (R 3 Sn) 2 NR" and (R 3 Sn) 3 N are formed. These are all useful in the present process. Sodium is a preferred alkali metal for use in preparing the alkali meta salts of the amine. Any nitrogenous compound having an N--H bond capable of reacting with a metalating agent to form an alkali metal amine salt is suitable for preparing the organotin amines used herein. Exemplary amines used in this procedure include methylamine, dimethylamine, ethylamine, diethylamine, decylamine, di-decylamine, cyclohexylamine, di-cyclohexylamine, ethylene diamine, and isopropylamine, as well as ammonia. Especially preferred herein are ammonia, methylamine, dimethylamine and diethylamine, for economic reasons.
The triorganotin halides suitable for preparing the organotin amines used herein are commercially available. Such compounds are prepared, for example, by reacting an organometallic compound with a tin tetrahalide in the manner well-known to those skilled in the art. Exemplary triorganotin halides suitable for preparing the organotin amines used in the present process include trimethyltin chloride, triethyltin bromide, tripropyltin fluoride, tributyltin chloride, triphenyltin iodide, trinaphthyltin chloride, tri-p-tolyltin chloride, tri-m-methoxyphenyltin iodide, tris-eicosyltin chloride and the like. The trialkyltin chlorides are preferred for economic reasons. Tributyltin chloride is most preferred herein.
From the foregoing it may be seen that a variety of organotin amines useful in the present process can be readily prepared using standard techniques. Preferred organotin amines used in the present process are the trialkyltin amines, especially the bis(trialkyltin)amines [(R 3 Sn) 2 NH], tris-(trialkyltin)amines [(R 3 Sn) 3 N], bis-(trialkyltin)-N-methylamines [(R 3 Sn) 2 NCH 3 ), aminotrialkyltins (R 3 SnNH 2 ), and N,N-di-methylaminotrialkyltins [R 3 SnN(CH 3 ) 2 ]. Of these, the compounds wherein R is butyl, e.g., aminotributyltin, (N-methylamino)tributyltin, (N,N-dimethylamino)tributyltin, bis-(tributyltin)amine, tris-(tributyltin)amine and bis-(tributyltin)-N-methylamine, are preferred. When ease of preparation and handling are of primary concern, (N,N-diethylamino)tributyltin or (N,N-dimethylamino)tributyltin are preferably used. For economy, tris-(tributyltin)amine is preferred.
The sulfolene compounds used in the reaction with the organotin amines to prepare the organotin-substituted sulfolenes can be either the isomeric 3-sulfolene or 2-sulfolene compounds, or mixtures thereof. The 3-isomers are preferred herein in that they are prepared directly from SO 2 and dienes of the formula CH 2 =CR'--CR'=CH 2 (R' as above) in well-known fashion. For example,, 1,3-butadiene, 2,3-dimethylbutadiene, 2-ethylbutadiene, 2,3-diphenylbutadiene, 2-tetradecylbutadiene, 2-naphthylbutadiene, 2-p-tolylbutadiene, 2-p-chlorophenylbutadiene, 2-o-methoxyphenylbutadiene, 2-isopropylbutadiene and isoprene are reacted with SO 2 to yield 3-sulfolene, 3,4-dimethyl-3-sulfolene, 3-ethyl-3-sulfolene, 3,4-diphenyl-3-sulfolene, 3-tetradecyl-3-sulfolene, 3-naphthyl-3-sulfolene, 3-p-tolyl-3-sulfolene, 3-p-chlorophenyl-3-sulfolene, 3-o-methoxyphenyl-3-sulfolene, 3-isopropyl-3-sulfolene and 3-methyl-3-sulfolene, respectively, all of which are suitable for use in the preparation of the organotin-substituted sulfolene compounds of this invention by means of the organotin amine reaction described above. Preferred herein for economic reasons are 3-sulfolene and 3-methyl-3-sulfolene.
Alternatively, the 3-sulfolene compounds are first isomerized to the 2-sulfolene isomers by treatment with base (e.g., NaOH, KOH, etc.) and can be used in the metalation procedure disclosed above to prepare the organotin-substituted 2-sulfolene compounds of this invention. In this general fashion, butadiene is reacted with SO 2 to yield 3-sulfolene; subsequent contact with aqueous NaOH yields 2-sulfolene useful in the synthesis of the organotin-substituted 2-sulfolenes by the metalation procedure. Similarly, reaction of SO 2 with isoprene followed by base treatment yields 3-methyl-2-sulfolene. In like manner, 2-phenyl-1,3-butadiene, 2-naphthyl-1,3-butadiene, 2-dodecyl-1,3-butadiene, 2,3-dimethylbutadiene, and 2-p-tolyl-1,3-butadiene are reacted with SO 2 and isomerized with base to yield 3-phenyl-2-sulfolene, 3-naphthyl-2-sulfolene, 3-dodecyl-2-sulfolene, 3,4-dimethyl-2-sulfolene and 3-p-tolyl-2-sulfolene, respectively, which are all useful in preparing the organotin-substituted 2-sulfolene compounds of this invention. Preferably, the 2-sulfolene compounds can be used with the organotin amines in the manner hereinabove detailed to prepare the compounds of this invention.
The sulfolane compounds used in conjunction with the organotin amines in the manner of this invention to prepare organotin-substituted sulfolanes are obtained by hydrogenation of any of the 2- and 3-sulfolenes disclosed above using well-known procedures. For example, hydrogenation of 3-sulfolene using a palladium-on-carbon catalyst yields sulfolane, which is suitable for use herein. Raney nickel hydrogenation of 3-methyl-3-sulfolene yields 3-methylsulfolane, which is also useful herein.
The preferred process of this invention is carried out by admixing the organotin amine with the 3-sulfolene isomer or sulfolane compound in accordance with the stoichiometry noted in the reaction schemem listed above (mole ratios of from about 1:100 to 100:1, preferably about 1:1 are suitable). The reaction mixture is heated at a temperature above about 40° C for a period from about 1 to about 72 hours, and the organotin-substituted sulfolene or sulfolane compound is recovered by crystallization, chromatography or distillation, depending on the physical form of the compound being prepared. For example, liquid organotin 2-sulfolene and sulfolane compounds are generally recovered by distillation while the solid organotin sulfolene and sulfolane and liquid 3-sulfolene compounds are readily recovered by column chromatography or crystallization. When sulfolenes are being prepared by this method, both the organotin-3-sulfolene and the organotin-2-sulfolene isomers are formed during the reaction due to isomerization. The isomer mixture can be separated into its components, e.g., chromatographically, if so desired and both isomers are useful as pesticides, and the like. Alternatively, and preferably from an economic standpoint, the isomers are not separated but are employed as mixtures as pesticides in the manner hereinafter described. Of course, the sulfolanes do not form double bond isomers.
While the process for preparing organotin-substituted sulfolenes and sulfolanes using organotin amines can be carried out without a solvent, it is sometimes convenient to use a solvent or suspending liquid herein. Any of the common organic solvents can be used for this purpose, including for example, hexane, benzene, toluene, xylene, and the like. Mixtures such as the petroleum ethers and the glyme solvents are also suitable. Preferred herein are anhydrous aprotic organic liquids, especially hexane. Sufficient liquid is used to dissolve or disperse the reactants.
The reaction temperature in the present process is not critical except that the temperature should be above about 40° C, more preferably from about 50° to about 150° C, to insure that the reaction will occur at a reasonable rate. Likewise, the reaction is initiated almost immediately and the reaction time employed will vary with temperature, the amount of organotin amine being reacted with the sulfolene or sulfolane compound, and the like. Usually, from about 10 minutes to 24 hours per mole of organotin-substituted sulfolene or sulfolane compound being prepared is sufficient.
The organotin-substituted sulfolene and sulfolane compounds, singly, as mixtures, and as isomer mixtures, are useful as insecticides, acaricides, bactericides, bacteriostats, fungicides, fungistats, and herbicides. The present invention also encompasses a process for combating pests comprising applying the organotin-substituted sulfolene and sulfolane compounds herein to loci infested with pests, i.e., insects, larvae, bacteria, fungi, or undesirable vegetation, either singly, in combination with one another or with other well-known pesticides, herbicides, and biocides, to provide the desired effects. Application rates are approximately those of other well-known herbicides, insecticides, and the like. For example, use of about 10 p.p.m. of the organotin-substituted sulfolene compounds in bacterial culture media kills substantially all the bacteria therein. Application of the organotin-substituted sulfolene compounds to undesired vegetation at a rate of from about 0.5 to about 50 pounds, more preferably about 1 pound to about 3 pounds, per acre results in herbicidal effects.
For practical use as herbicides, insecticides and the like, the organotin-substituted sulfolene and sulfolane compounds herein are incorporated into compositions comprising a carrier and an effective, i.e., herbicidal, bacteriostatic, fungicidal, or insecticidal, amount of one or more of the organotin-substituted sulfolene or sulfolane compounds. (As used herein, the term "carrier" is defined as an inert solvent or dry bulking agent of the type hereinafter disclosed which has no substantial insecticidal, herbicidal, etc., effectiveness, but which provides a means whereby the organotin-substituted sulfolene and sulfolane compounds can be diluted for convenient application.) Such compositions can then be applied conveniently in any desired quantity. These compositions can be solids, such as dust, granules, or wettable powders, or they can be liquids such as solutions, aerosols, or emulsifiable concentrates. The solid compositions generally contain from about 1 to about 95% by weight of the organotin-substituted sulfolene or sulfolane compounds and the liquid compositions generally contain from about 0.5 to about 70% by weight of said compounds.
The organotin-substituted sulfolene and sulfolane compounds herein are conveniently applied as solutions, emulsifiable concentrates, wettable powders, dusts, aerosols and the like. Suspensions or dispersions of the compounds of this invention in a non-solvent, such as water, are suitable, as are solutions of the insecticides, acaricides, herbicides, and fungicides of this invention in oil which is emulsified in water. Examples of oil solvents include hydrocarbons such as benzene and toluene, kerosene, Stoddard solvent, and halogenated hydrocarbons such as chlorobenzene, chloroform, fluorotrichloromethane and dichlorodifluoromethane.
Emulsifiers and wetting agents are also useful in the compositions herein. Such materials are surface active agents of the anionic, nonionic (preferred), cationic, ampholytic and zwitterionic type and normally comprise from about 0.1 to 5% by weight of the compositions herein. Examples of suitable anionic surface active agents are sodium salts of fatty alcohol sulfates having from 8-18 carbon atoms in the fatty chain and sodium salts of alkyl benzene sulfonates having from 9 to 15 carbon atoms in the alkyl chain. Examples of suitable nonionic surface active agents are the polyethylene oxide condensates of alkyl phenols, wherein the alkyl chain contains from about 6 to 12 carbon atoms and the amount of ethylene oxide condensed onto each mole of alkyl phenol is from about 5 to 25 moles. An especially preferred nonionic herein is the polyethylene oxide condensate of sorbitan mono-oleate (Tween). Examples of suitable cationic surface active agents are dimethyl dialkyl quaternary ammonium salts wherein the alkyl chains contain from about 8 to 18 carbon atoms and the salt forming anion is a halogen. Examples of suitable ampholytic surface active agents are derivatives of aliphatic secondary or tertiary amines in which one of the aliphatic substituents contains from about 8 to 18 carbon atoms and one contains an anionic water solubilizing groups, e.g., sulfate or sulfonate. Specific suitable ampholytic surface active agents are sodium-3-dodecylaminopropionate and sodium-3-dodecyl amino propane sulfonate. Examples of suitable zwitterionic surface active agents are derivatives of aliphatic quaternary ammonium compounds in which one of the aliphatic constituents contains from about 8 to 18 carbon atoms and one contains an anionic water solubilizing group. Specific examples of zwitterionic surface active agents are 3-(N,N-dimethyl-N-hexadecylammonio)propane-1-sulfonate and 3-(N,N-dimethyl-N-hexadecylammonio)-2-hydroxy propane-1-sulfonate. Many other suitable surface active agents are described in "Detergents and Emulsifiers -- 1969 Annual", by John W. McCutcheon, Inc., which is incorporated by reference herein. Suitable solvents for emulsifiable concentrates comprising the organotin-substituted sulfolene or sulfolane compounds and an emulsifier include hydrocarbons such as benzene, toluene, xylene, kerosene and Stoddard Solvent and halogenated hydrocarbons such as chlorobenzene, chloroform, and the like.
Aerosols prepared by dissolving the compounds of this invention in a highly volatile liquid carrier such as trifluorochloromethane, nitromethane, and the like, or by dissolving such compounds in a less volaile solvent, such as benzene, and admixing the resulting solution with a highly volatile liquid aerosol carrier, can also be employed to advantage.
Compositions in the form of dusts can be prepared by admixing the compounds of this invention with dry free-flowing powders such as clay, bentonite, fuller's earth, diatomaceous earth, pyrophyllite, attapulgite, calcium carbonate, chalk and the like. Wettable dusts also include from about 0.1 to 5% by weight of one or more of the surface active agents described above.
Preferred compositions herein suitable for use as pesticides, i.e., insecticides, acaricides, herbicides, bactericides and fungicides, comprise from about 1 to about 10% by weight of one or more of the organotin-substituted sulfolene or sulfolane compounds disclosed herein (the sulfolenes are preferred for economic reasons), from about 0.1 to about 5% by weight of a surface active agent of the type hereinabove disclosed, and from about 85 to about 99% by weight of a carrier. Preferred organotin-substituted sulfolene compounds in such compositions are 2-tributyltin-3-methyl-2-sulfolene, 2-tributyltin-3-methyl-3-sulfolene, 2-tributyltin-2-sulfolene, 2-tributyltin-3-sulfolene, and mixtures thereof; preferred sulfolanes are 2-tributyltinsulfolane and 2-tributyltin-3-methylsulfolane. Preferred surface active agents in such compositions are the nonionics, especially the polyethylene oxide condensates of sorbitan monooleate. Preferred carriers in such compositions include acetone, water, kerosene, Stoddard solvent, and mixtures thereof.
The following examples are intended to illustrate the compounds, compositions and processes of this invention but are not intended to be limiting thereof. The sulfolene compounds used in the processes are available commercially or can be prepared by reacting sulfur dioxide with a diene in the manner well-known in the art.
EXAMPLE I
Preparation of 2-Tributyltin-3-methyl-2-sulfolene
5.0 g. of 3-methyl-2-sulfolene was dissolved in 220 ml. of tetrahydrofuran (THF) at -65° C. 2.56 g. of 1.6 molar n-butyllithium was added to the sulfolene-THF solution over 20 minutes; the solution was stirred at -65° C for about 45 minutes. 13.5 g. of tributyltin chloride (10% excess) was added dropwise to the above solution at -65° C. The reaction mixture was stirred for about 1 hour and the solvent evaporated. The liquid residue was dissolved in chloroform and solid LiCl removed by filtration. The liquid recovered by the evaporation of the chloroform was analyzed and corresponded to 2-tributyltin-3-methyl-2-sulfolene.
In the above procedure, the tributyltin chloride is replaced by an equivalent amount of triphenyltin bromide, tri-p-toyltin iodide, tri-o-methoxyphenyltin chloride, trinaphthyltin chloride and tri-hexadecyltin bromide, respectively, and the compounds 2-triphenyltin-3-methyl-2-sulfolene, 2-tri-p-tolyltin-3-methyl-2-sulfolene, 2-tri-o-methoxyphenyltin-3-methyl-2-sulfolene, 2-tri-naphthyltin-3-methyl-2-sulfolene and 2-trihexadecyltin-3-methyl-2-sulfolene, respectively, are secured.
In the above procedure, the 3-methyl-2-sulfolene is replaced by an equivalent amount of 2-sulfolene, 3-octyl-2-sulfolene, and 3-phenyl-2-sulfolene, respectively, and the compounds 2-tributyltin-2-sulfolene, 2-tributyltin-3-octyl-2-sulfolene, and 2-tributyltin-3-phenyl-2-sulfolene, respectively, are secured.
EXAMPLE II
Reaction of 3Methyl-3-sulfolene with (N,N-dimethylamino)tributyltin
To a mixture comprising 9 g. of dimethylamine in 100 ml. of dry hexane at 0° C was added 100 ml. of 1.6 molar butyllithium in n-hexane at a rate such that the temperature remained less than about 10° C. The solution was stirred for 1 hour at ambient temperature. Tributyltin chloride (52.6 g.) was added dropwise to the stirred reaction mixture at 10° C and the reaction mixture was allowed to warm to room temperature with stirring for about 1 hour. The lithium chloride whch had formed was filtered and the hexane removed by evaporation to yield (N,N-dimethylamino)tributyltin.
10.0 g. of (N,N-dimethylamino)tributyltin, prepared above, and 4.0 g. of 3-methyl-3-sulfolene (commercial material) were mixed in a 25 ml. flask and stirred at 75° C for 4 hours. An NMR spectrum of the reaction material indicated that no N--CH 3 groups remained in the reaction mixture, indicating a loss of dimethylamine. The reaction mixture was chromatographed on 150 g. of silica gel and yielded a material which proved to be a mixture of 2-tributyltin-3-methyl-2-sulfolene and 2-tributyltin-3-methyl-3-sulfolene.
In the above procedure the (N,N-dimethylamino)-tributyltin is replaced by an equivalent amount of (N,N-dimethylamino)triphenyltin, (N,N-dimethylamino)-tri-p-tolyltin, (N,N-diethylamino)tri-m-chlorophenyltin, (N-methylamino)tri-o-fluorophenyltin, tris-(tri-m-nitrophenyltin)amine and aminotri-tetradecyltin, respectively, and mixtures of the corresponding organotin-substituted 2- and 3-sulfolene isomers are secured.
EXAMPLE III
Reaction of 3-sulfolene with tris-(trialkyltin)amines
A 500 ml. flask is fitted with a cold finger condenser cooled with a dry-ice acetone mixture and blanketed with argon gas. Anhydrous ammonia gas is condensed into the reaction flask (ca. 300 ml. liquified gas). 0.08 g. of iron (III) chloride and 2.57 g. of sodium metal are added to the flask portion-wise over 30 minutes. After hydrogen evolution ceases, tributyltin chloride (ca. 0.1 mole) is added dropwise to the reaction mixture; a black oily material [mixture of mono-, bis- and tris-(tributyltin)amine] is formed. 250 ml. of diethyl ether is added to the reaction vessel to disperse the oily material and 0.10 of 3-sulfolene is added thereto. The reaction mixture is stirred for about 30 minutes, and the ammonia and ether allowed to evaporate, leaving a black residue. The residue is heated at about 100° C for approximately 5 hours, washed with 100 ml. of aqueous 1M NH 4 Cl and extracted with 3 × 200 ml. portions of diethyl ether. The product is chromatographed on silica gel and provides a mixture of 2-tributyltin-3-sulfolene and 2-tributyltin-2-sulfolene.
In the above procedure, the 3-sulfolene is replaced by an equivalent amount of 2-sulfolene, 3,4-dimethyl-3-sulfolene, 3-ethyl-4-phenyl-3-sulfolene, 3-naphthyl-4-decyl-3-sulfolene, and 3,4-dioctyl-2-sulfolene, respectively, and the following are secured: 2-tributyltin-2-sulfolene; isomer mixtures of 2-tributyltin-3,4-dimethyl-3-sulfolene, and 2-tributyltin-3,4-dimethyl-2-sulfolene; 2-tributyltin-3-ethyl-4-phenyl-3-sulfolene and 2-tributyltin-3-ethyl-4-phenyl-2-sulfolene; 2-tributyltin-3-naphthyl-4-decyl-3-sulfolene and 2-tributyltin-3-naphthyl-4-decyl-2-sulfolene, and; 2-tributyltin-3,4-dioctyl-2-sulfolene and 2-tributyltin-3,4-dioctyl-3-sulfolene.
In the above procedure the tributyltin chloride is replaced by an equivalent amount of tributyltin bromide, trioctyltin fluoride, trinaphthyltin iodide, tri-p-tolyltin fluoride, and tri-p-methoxyphenyltin iodide, respectively, and the corresponding trialkyltin- and triaryltin-substituted sulfolene isomers are secured.
In the above procedure, the ammonia is replaced by an equivalent amount of methylamine, butylamine, octylamine, phenylamine, dioctylamine and diphenylamine, respectively, and the reaction is carried out at temperatures of 40 C, 75° and 125° C, respectively, and equivalent results are secured.
EXAMPLE IV
Reaction of Sulfolane with (N,N-dimethylamino)tributyltin
Using the apparatus of Example I, above, 3.6 g. of sulfolane and 10.2 g. of (N,N-dimethylamino)tributyltin were admixed and heated at 150° C for 72 hrs. The reaction product was distilled through a short-path, semi-micro still and the distillate recovered at 160°-170° C (0.05 mm.) was purified further by chromatography. Spectral analysis of the pure product indicated that it corresponded to 2-tributyltin sulfolane. The pot residue from the distillation was found to be 2,5-(bis-tributyltin)sulfolane.
In the above procedure, the sulfolane is replaced by an equivalent amount of 3-methylsulfolane and 3-phenylsulfolane, respectively and the compounds 2-tributyltin-3-methylsulfolane and 2-tributyltin-3-phenylsulfolane are secured.
In the above procedure, the (N,N-dimethylamino)tributyltin is replaced by an equivalent amount of tris(tributyltin)amine, bis-(tributyltin)amine, tris-(triphenyltin)amine, and (N,N-diethylamino)tributyltin, respectively, and equivalent results are secured.
EXAMPLE V
______________________________________Insecticidal CompositionIngredient % (wt.)______________________________________2-tributyltin-3-methyl-2-sulfolene* 0.5Acetone 10.0Triton X-100** 0.1Water Balance______________________________________ *Prepared in Example I, above. **(Iso-octylphenypolyethoxyethanol)
The 2-tributyltin-3-methyl-2-sulfolene is dissolved in the acetone and dispersed in the water using the Triton X-100 emulsifier. The composition is sprayed onto adult houseflies, southern army worm larvae, Mexican bean beetle larvae and adult pea aphids as a pressurized spray and the insects are killed.
In the above composition, the 2-tributyltin-3methyl-2-sulfolene is replaced by an equivalent amount of 2-tributyltin-2-sulfolene, 2-trioctyltinsulfolane, 2-triphenyltin-3-methyl-2-sulfolene, 2-tributyltin-3-sulfolene, and a 1:1 mixture of 2 -tributyltin-3-methyl-3-sulfolene and 2-tributyltin-3-methyl-2-sulfolene, respectively, and equivalent results are secured.
EXAMPLE VI
______________________________________Acaricidal CompositionIngredient % (wt.)______________________________________Mixture of 2-tributyltin-3-methyl-2-sul- 1.0 folene and 2-tributyltin-3-methyl-3- sulfolene*Acetone 10.0Sorbitan mono-oleate polyoxyethylene 0.25Water Balance______________________________________ *Isomer mixture prepared in Example II, above.
The tributyltin-substituted sulfolene isomer mixture is dissolved in the acetone and dispersed in the water using the sorbitan mono-oleate polyoxyethylene emulsifier. The composition is sprayed onto bean sprouts infested with the strawberry spider mite and substantially all of the mites are killed within a 24 hour period.
In the above composition, the acetone is replaced by an equivalent amount of kerosene, Stoddard solvent, and ethanol, respectively, and equivalent results are secured.
In the above composition, the sorbitan mono-oleate polyoxyethylene is replaced by an equivalent amount of a mixture of C 8 -C 18 fatty alcohol sulfates, sodium salt form, a mixture of alkyl (C 9 -C 15 ) benzene sulfonates, sodium salt form, sodium-3-dodecylaminopropionate, and trimethyltetradecylammonium chloride emulsifiers, respectively, and equivalent results are secured.
EXAMPLE VII
______________________________________Herbicidal ConcentrateIngredient % (wt.)______________________________________1:1 mixture of 2-tributyltin-2-sulfolene 50 and 2-tributyltin-3-sulfoleneKerosene 49Sorbitan mono-oleate polyoxyethylene 1.0______________________________________
The above concentrate is admixed with water at a ratio of about 1 pound of concentrate per 100 gallons of water and provides an emulsion. The emulsion is applied to a field infested with pigweed, wild mustard, barnyard grass, and hairy crabgrass at a rate of about 50 gel./acre and the growing weeds are substantially controlled. Seeds from the respective weeds treated in this mannder do not germinate.
The above emulsion is applied to fields planted in corn, soybeans and wheat, at a rate of about 100 gallons per acre and both pre-emergent and post-emergent control of pigweed, wild mustard, barnyard grass, and hairy crabgrass are secured. The growing crops are not substantially damaged by this treatment and are coated with a non-toxic residue of tin oxide at harvest.
As can be seen from the foregoing, the organotin-substituted sulfolene and sulfolane compounds herein can be used to advantage in a variety of pesticidal applications. Furthermore, the compounds herein leave non-toxic tin oxide residues on the treated substrates. Because of the wide biocidal activity of the compounds herein, they are also suitable for use as seed protecting agents. That is to say, seeds treated with one or more of the herein disclosed organotin-substituted sulfolene or sulfolane compounds are protected from the phytopathogenic fungi, especially those of the genus Fusarium. Furthermore, the insecticidal and fungicidal activity of the compounds herein make them admirably suitable for use as wood preservatives in that they protect wood from the ravages of such biological agents as dry rot fungi, sap stain fungi, and all manner of insects, especially termites, boring beetles, and the like. Therefore, it is to be recognized that the process for combating pests herein is intended to encompass these seed protection and wood preserving aspects of the present invention.
The following examples are intended to describe the seed protecting and wood preserving uses of the organotin-substituted sulfolene and sulfolane compounds, but are not intended to be limiting thereof.
EXAMPLE VIII
Pythium sp. and Rhizoctonia sp. organisms are thoroughly mixed with soil prepared from three parts loam and two parts seed. A 1:1 mixture of 2-tributyltin-2-sulfolene and 2-tributyltin-3-sulfolene is applied to pea seeds at the rate of 12/3 ounces per 100 pounds of seed by immersion in a dispersion of the organotin compounds in 5% acetone/1% Tween 20/94% water. A substantial increase in the percentage of germinating seeds is achieved with the organotin treated seeds compared with untreated seeds planted in the infested soil.
Equivalent seed protection is secured when seeds are treated with 2-tributyltinsulfolane at 12/3 oz. per 100 pounds of seed.
EXAMPLE IX
A wood preservative paint composition is prepared as follows:
______________________________________Ingredient % (Wt.)______________________________________1:1 Mixture of 2-tributyltin-2- 10 sulfolene and 2-tributyltin- 3-sulfoleneTitanium dioxide 50Linseed oil 40______________________________________
The paint is applied to Loblolly pine and gives effective protection against the dry rot fungus, L. trabea, as well as against termites and boring beetles. The above composition is applied to wood pilings as an anti-fouling paint and prevents the accumulation of mollusks and barnacles thereon.
In the above composition, the mixture of sulfolene compounds is replaced by an equivalent amount of 2-tributyltinsulfolane, 2-triphenyltin-3-sulfolene, 2-tri-α-chloronaphthyltin-2-sulfolene, 2-tricyclohexyltin-3-sulfolene, 2-tributyltin-3-phenyl-3-sulfolene, 2-trimethyltin-3-α-nitronaphthyl-2-sulfolene, 2-triphenyltinsulfolane, 2-tri-p-propoxyphenyltinsulfolane, and 2-triphenanthryltin-3,4-di-p-bromophenyl-2-sulfolene, respectively, with equivalent results.
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Novel organotin-substituted cyclic sulfone compounds of the general formula: ##SPC1##
Where each R is alkyl of from 1 to about 14 carbon atoms, or aryl and each R' is alkyl of from 1 to about 14 carbon atoms, aryl or hydrogen, and a process for preparing same. These organotin compounds have insecticidal, acaricidal, bacteriostatic, fungicidal and herbicidal properties.
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BACKGROUND
The present invention relates to wall structure and manufacturing methods therefor and, more particularly, to a load-bearing structural assembly comprising a plurality of individual components interconnected to form an integrated unitary structure without requiring or utilizing a pre-erected framing structure.
Heretofore, in the erection of buildings of almost any type it has been customary to erect suitable framing structure in order to provide strength, rigidity, load-bearing capacity, etc., commensurate with forces and/or loads which the building structure is intended to withstand. Thereafter, other building components were suitably connected to the previously erected framing structure. Such other components included, but were not necessarily limited to, inner and outer walls, floors, ceilings, and roof panels for enclosing or subdividing space within the framing structure. Certain walls and floors were designed as load-bearing components while others were not necessarily intended for a load-bearing function.
Although concrete has been used successfully in at least some of the aforementioned building components, the use of concrete involves certain disadvantages. For example, concrete is a relatively heavy material. Thus, the use of components formed of concrete adds to the loads or forces that the building framework or other supporting structure is designed to withstand. The additional weight of such components may be quite substantial.
Additionally, certain types of components are not suitable for the utilization of pre-casting and/or mass production techniques and thus require the pouring of concrete in the field at the job site. This is both wasteful and costly since it requires the acquisition of costly forms as well as the labor expense for the erection thereof, the dismantling and/or cleaning and oiling of such forms after the concrete pouring operation has been completed.
Additionally, concrete lacks tensile strength and is therefore not suitable for the manufacture of structural components which will be subjected to tensile forces and/or flexural forces.
Accordingly, it is a principal object of the present invention to provide means and method for obviating the above-mentioned and other difficulties and limitations.
SUMMARY
These and other objects and advantages are achieved in accordance with the present invention by the provision of a pre-cast panel of suitable thickness and other dimensions and having opposed surfaces that may be either flat or suitably curved as desired.
Preferably, such a panel is formed of a fast setting cement material with reinforcing material disposed adjacent each of the aforesaid surfaces. Edge portions of the panel have a notch or channel extending along said portions with reinforcing material in the channel and extending along or parallel to said edges. When such panels are clamped together in abutting relationship, the void space defining the channels provides a mold cavity into which cement material is injected and, after setting, forms a load-bearing beam such as a column, rib, stud, joist, and the like, without requiring or utilizing a pre-erected supporting framework. After setting of the injected material, the two panels are then permanently interconnected and form an integrated unitary monolithic wall structure that is useful in the construction of many differing types of structures including receivers of solar and other kinds of radiant energy.
DESCRIPTION
Additinal objects and advantages of the invention will become apparent from the following description taken in connection with the accompanying drawings in which:
FIG. 1 is a perspective view, partly broken, of a building structure embodying the present invention;
FIG. 2 is a sectional view, partly broken, illustrating a typical outer wall and floors of the embodiment of FIG. 1;
FIGS. 3-5 are perspective views of typical panels embodying the present invention;
FIG. 6 is a fragmentary sectional view illustrating abutting panels joined together in accordance with the invention;
FIG. 7 is a fragmentary sectional view showing adjacent panels joined together and forming a corner;
FIG. 8 is a perspective view, partly broken, of a typical roof section embodying the present invention;
FIG. 9 is a fragmentary sectional view of a typical floor panel;
FIG. 10 is a sectional elevational view of an elongated trough structure embodying the present invention;
FIG. 11 is a sectional view looking in the direction of arrows 11--11 of FIG. 10;
FIG. 12 is a top plan view illustrating a saucer or dome structure in accordance with the present invention;
FIG. 13 is a sectional view taken along a diameter of FIG. 1; and
FIG. 14 is a fragmentary sectional view illustrating a typical joint connecting adjacent curved panels of FIGS. 10-13 inclusive.
Referring now to the drawings, a typical building structure embodying the present invention is illustrated generally at 10. It is to be understood that the illustrations and descriptions in connection with such building structure are intended as being illustrative and not limiting since the present invention is useful in connection with the construction of many differing types of building structures.
As is best shown in FIG. 1, a typical building structure embodying the present invention comprises a plurality of components such as basic wall panels 11, roof section 14, and floor panels 17, which components are fabricated by mass production techniques in a suitable manufacturing facility. These basic components may include minor modifications for particular purposes and yet the number of different basic components is kept to a minimum and, if desired, the various panels and/or other components can be standardized regarding their size including width, length, and thickness dimensions to further minimize the number of differing components that might be required. For example, a basic wall panel 11 can be formed of any desired thickness and may be either square or rectangular in shape as is best shown in FIG. 3. Also, the structure and configuration of the panels is such as to permit the inclusion therein of electrical or plumbing conduits and boxes 15, 15a as shown in FIG. 3. Similarly, basic panel 11 may be modified to include as part of its structure a door frame as illustrated by panel 12, or a window frame as illustrated by panel 13. Also, edge portions of basic panels may be modified to provide corner panels such as 16. Except for the above-mentioned details, the basic structure of all panels 11-16 is identical or substantially identical.
A panel embodying the present invention may be formed of a castable material that is initially plastic and which hardens after setting such as concrete, synthetic resinous materials, cement, and the like. In accordance with the present invention, the outer surfaces of such a panel can be of any desired texture and/or may include any design that may be desired from an aesthetic or architectural viewpoint.
The material from which the panel is formed may be or may contain a foamed or foamable material such as polyurethane and the like. It is desirable that a material utilized to form a panel in accordance with the present invention be one having properties, both physical and chemical, that are stable and are not subject to deterioration with age as a result of decay or a similar defect. It is also desirable that such material be fire resistant or incombustible, and that it be resistant to and unattractive to ants, termites, and the like as well as other pests.
On the basis of information presently available, a panel embodying the present invention preferably is formed of a homogenous material such as a fast setting cement with or without a plurality of cellular air-containing cavities contained within the material thereby providing a resultant structure that is relatively light in weight and having good thermal and/or sound insulating properties. Foamed cement of controllable density is now available commercially as is well-suited in connection with mass production techniques which are desirably to be employed in forming a panel embodying the present invention. If desired, the cement material may have interspersed therein an additive such as pellets of styrofoam and the like.
A panel embodying the present invention is formed in a suitable mold, now shown, since the details of suitable mold structure are well known and are not necessary to an understanding of the present invention. It will suffice to state that the mold surfaces have a configuration to produce whatever configuration, texture, and/or design may be desired on the surface of the panel to be formed.
Before the casting procedure is initiated, reinforcing material is positioned within the mold cavity at desired locations in accordance with well known procedures and techniques similar to those employed in the production of objects formed of concrete whether such objects are pre-cast or are poured in suitable molds erected at the job site. In accordance with the present invention, a layer of reinforcing mesh 18 is provided and positioned adjacent each of the opposed surfaces of the resultant panel, as is best shown in FIG. 6. In order to insure that these two layers of mesh are properly positioned relative to other portions of the panel to be formed and remain so positioned during pouring operations, these two mesh layers are suitably connected by any convenient means, for example, by welding, to frame members 19, each of which is continuous and extends completely around the peripheral edge of the panel to be formed, and a suitable separator 20 is positioned between the respective mesh layers.
In FIG. 6, there are shown in abutting relationship two adjacent panels 11, 11', each having like structural components. The prime designation has been added to the reference numerals in order to clearly distinguish between the corresponding components of the right and left-hand panels. The peripheral edge portions of panel 11 are defined by the opposed frame members 19 and separator member 20. The corresponding peripheral edge portions of panel 11' are similarly defined by opposed frame portions 19' and separator member 20'.
In addition to providing desired spacing and positioning means, opposed frame members 19 additionally provide means for applying tensile stress to the opposed reinforcing mesh structures 18 which, preferably, are connected to members 19 while subjected to such stress, to prevent sagging of these mesh structures. The ends of each of these reinforcing mesh structures project outwardly beyond the peripheral edges of panel 11. Each of these projecting end portions terminates at an end designated 18a and they are curved in opposite directions and are superimposed one upon the other to form a substantially closed loop extending outwardly beyond the peripheral edge portions of panel 11. The corresponding ends of mesh structures 18' of panel 11' similarly terminate in end portions designated 18a' and are similarly curved and superimposed for reasons which will become apparent as the description proceeds.
Thus, as best shown in FIG. 6, the vertical portions of frame members 19 define the outermost extremities of the peripheral edge portion of panel 11. The horizontal portions of frame members 19 define opposed sidewalls of a notch or channel which extends inwardly from said outer peripheral portions, the innermost boundary or margin of said channel being defined by spacer member 20. This outwardly projecting channel is open adjacent the outer marginal periphery of panel 11 and extends completely around the peripheral edges of said panel. A corresponding channel similarly extends completely around panel member 11'. When these two panel members are placed in abutting relationship, as shown in FIG. 6, the respective channels cooperatively define a closed cavity extending along the entire length of the abutting edges of these panels and disposed between opposed surfaces 21, 22 thereof.
Referring now to FIGS. 2 and 6, a pair of reinforcing members 24, 25 are connected to the lower and upper mesh structures 18, respectively, and extend along and substantially parallel to the outer peripheral margins of panel 11. Interconnected with and between members 24, 25 is another reinforcing member 23 which extends generally along and substantially parallel to the peripheral outer edge portions of panel 11 and forms a truss-like structure as is best illustrated in FIG. 2. This truss-like structure comprising members 23-25 inclusive, extends continuously and peripherally along all edges of panel 11 within the aforesaid open channel and adjacent but spaced apart from the central portion of member 20 as is best shown in FIG. 6.
After the above described components have been positioned and secured within a mold cavity the information of the panel is completed by well known casting procedures and, after setting of the castable material, the formation of the panel is complete and it can then be removed from the mold. While the positioning of components has been described in reference to a single panel 11 and pouring within a single mold structure, it is to be understood that the use of multiple molds or multiple cavity molds and continuous pouring techniques are contemplated within the scope of the present invention as well as any other techniques that are well suited for mass production of such panels. Normal manufacturing tolerances present no problems regarding manufacture, use, or assembly of structural components embodying the present invention.
In accordance with the present invention, a pre-erected framing structure is neither required nor utilized in the assembly of a building, walls, or other components. Two adjacent panels 11, 11' are aligned and placed in abutting relationship, as shown in FIG. 6. After the surfaces 21, 22 are plumbed or leveled, as the case may be, the panels are clamped together and a plug or gasket 26 may be interposed therebetween. When so positioned and clamped, the inwardly extending open channels in each of their respective edges then defines an enclosed cavity which extends along the entire length of the abutting peripheral edge portions. Within said cavity there is then disposed the looped end portions of the reinforcing mesh 18, 18' as well as the truss-like reinforcing members 23, 24, 25 and 23', 24', 25', as is best shown in FIG. 6. Castable material which can be the same as that employed in the formation of the individual panels is then injected into said enclosed cavity, preferably from the bottom upwardly, to avoid possible entrapment of air within the enclosed cavity and to insure that said cavity is completely filled with the injected material. After the injected material has set, it hardens and forms a monolithic structure in which the adjacent panels are securely bonded to and form a unitary structure in which the material injected into the aforesaid cavity is now also securely bonded to the reinforcing members and thereby forms a strong, load-bearing structural member such as a beam, column, post, rib, and the like. In the event that one or more peripheral edges of a panel 11 are not to be so joined to another panel, member 20 is positioned substantially flush with the outer edges of frame members 19.
In FIG. 7, there is illustrated a modification of the basic panels wherein like components bear like designations. Panels 16, 16' are essentially identical with basic panels 11, 11'. They differ principally in the provision of a modified frame 19a, 19a' and mitered corners 22a, 22a' so that panels 16, 16' can be angularly disposed relative to one another in the formation of a corner joint. In FIG. 7, the spacing between surfaces 22a, 22a' is actually very small but is shown on an enlarged scale for purposes of clarity.
In the construction illustrated in FIG. 7, the peripheral edge portions of surfaces 21, 21' are spaced apart, thereby leaving an opening that extends along the length of the corner formed by adjacent panels 16, 16'. Accordingly, there is provided an additional panel member 27 having angularly disposed outer surfaces 21a, 21a' angularly disposed relative to one another for closing said opening.
Panels 16, 16' have peripheral edge portions which define a notch or channel, the cross-sectional shape of which is defined by that portion of frame 19 that is shown parallel to surface 21 and by the spacer member 20. A similarly shaped complimentary channel is formed along the peripheral edge portion of panel 16', and the corner opening resulting from the spacing between frame members 19, 19' is closed by inner surface 22b and portions of frame members 19b of corner member 27. When panels 16, 16' and corner member 27 are positioned and clamped together, as shown in FIG. 7, the inner surfaces of corner member 27 and the channels formed in the peripheral edges of panels 16, 16' define an enclosed cavity into which cement material is injected and which, after setting, forms a central corner post or column and provides a monolithic structure in which panels 16, 16' and corner member 27 are securely connected together to from a unitary structure.
The roof panel shown in FIG. 8 is also essentially like panel 11 shown in FIG. 6. Again, like components bear like designations. Roof panel 14 differs principally in that upper and lower surfaces 21b and 22b are angularly disposed relative to one another and one or more ports 28 are provided along and adjacent peripheral edges of surface 22b to facilitate the injection of cement material into the enclosed cavity defined between adjacent roof panels when they are aligned and clamped together.
FIG. 9 shows a floor panel which is essentially like panel 11. Again, like components bear like designations. Floor panel 17 differs from panel 11 primarily in that its thickness may be increased to provide additional strength and also may include additional truss-like reinforcing members 23a to provide additional strength. If desired, the shape of spacer member 20a may be varied, and one or more projection ports 28 may be provided along an adjacent peripheral edge portions of lower surface 22. If a foundation panel is required, it can be constructed essentially like the floor panel 17 except that ports 28 can be eliminated.
The present invention is not limited to panels and/or walls having flat or substantially flat outer surfaces. The invention is equally applicable and useful in connection with the erection of dome or saucer-like wall structures and/or trough-like vessels from curvilinear panel components and/or a combination of rectilinear and curvilinear panel components.
For example, in FIGS. 10-11, an elongated trough-like wall structure having curved wall panel portions is illustrated generally at 30. The trough-like structure comprises a plurality of panel portions 33 all of which are identical, as well as other panel portions that are similar, such as 31, 35 and 32, 34. Panel portions 31-35 inclusive all have components that are identical with those described above in connection with panel 11 in FIG. 6 including reinforcing meshes 18, frames 19, and integrally connected truss-like members 23, 24, 25.
Similarly, in FIGS. 12 and 13, a saucer or dome-like wall structure is designated generally at 36. The saucer or dome-like structure comprises a central panel having a circular peripheral margin and having either flat or curved opposed surfaces, a plurality of panel portions 28 that are essentially pie-shaped and having opposed curved wall surfaces; as well as a plurality of other wall portions 39 having quadrilateral peripheral edge portions and having curved and opposed surface portions. Panels 37-39 inclusive also include individual components like those described in connection with FIG. 6 including meshes 18, frames 19, and integrally connected truss-like reinforcing members 23, 24, 25.
A typical joint useful for interconnecting adjacent panels of the type shown in any of the foregoing figures, i.e., flat and/or curved is illustrated in FIG. 14. The joint illustrated in FIG. 14, as well as the load-bearing member formed by the injection of cement material into the enclosed cavity defined by the notches and/or channels formed in adjacent panel members after they have been aligned and clamped together is identical to that shown and described in connection with FIG. 6.
In certain instances, it may be desirable to apply to panel surfaces 21, 22 a protective coating of material such as a penetrating epoxy resin to obtain whatever surface characteristics may be desired such as, for example, sealing, weather and/or abrasion resistance, resistance to the formation of shrinkage cracks, and the like, and generally to maintain an attractive appearance and desired aesthetic effect. Additionally, it may be desirable to apply to exposed portions of the joint panels adjacent and along the juncture a suitable sealing and/or protective material such as an epoxy resin prior to the insertion of plug 26.
From the foregoing, it is believed that it will be readily apparent that the panel components and/or the method of construction of structure according to the concept of the present invention is quite different from methods employed heretofore. According to the present invention, the need for the erection of a framing structure prior to the erection of wall components is eliminated, as well as the need for concrete forms, their care and cleaning and overall maintenance, labor costs connected with their erection and dismantling at the job site after completion of concrete pouring operations. Instead, the present invention contemplates the provision of components which are pre-cast in a shop by mass production techniques. According to the invention, such pre-cast panels can be manufactured in a relatively small number of configurations that differ from one another but otherwise can be more or less standardized as to configurations, dimensions, shapes, curvature, etc.
When it is desired to erect a wall structure in accordance with the present invention, the appropriate number and kind of panel portions is selected and supplied to the job site. Appropriate individual panels are aligned and plumbed or leveled and then clamped together in desired configuration, following which fast setting cement material of appropriate density is injected into the enclosed cavity which formed when adjacent panel edge portions are clamped together. Upon completion of the injection process and upon setting of the cement material, the joint between adjacent panels then includes a load-bearing, frame-like member integrally connecting said member and each of the adjacent panel portions to form a unitary monolithic structure. By the selection of the limited number of panel configurations, a wide variety of ultimate wall structures can be formed with opposing wall surfaces of the resulting structure disposed relative to one another in virtually unlimited number of differing configurations.
As noted heretofore, the individual panels are formed of a material which hardens upon setting to provide a durable wall structure, and the manufacturing method in accordance with the present invention enables the use of opposing surfaces of the individual panels to be of almost any desired texture or design configuration in order to provide whatever overall aesthetic or architectural effect may be desired. Additionally, the mass production techniques contemplated by the present invention enable the formation of individual panels, as well as the erection of a wall structure of widely differing configurations therefrom, to be accomplished simply and economically at reasonable cost, and avoids unnecessary cost expenditures through the elimination of procedures, labors, and equipment that is not essential and does not form a part of the ultimate wall structure to be produced.
While particular embodiments of the invention have been illustrated and described, it will be obvious that various changes and modifications can be made without departing from the invention and it is intended in the appended claims to cover all such changes and modifications that fall within the true spirit and scope of the invention.
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The present invention relates to wall structure and components thereof and manufacturing methods therefor and, more particularly, in view of present energy crisis considerations, to a structural assembly comprising a plurality of individual components interconnected to form an integrated unitary structure of desired configuration such as but not limited to parabolic and/or other curved surfaces forming troughs, saucers, domes, flat wall structures and/or combinations thereof, some of which have particular utility in connection with reception and collection of various kinds of radiant energy including solar energy, without requiring or utilizing a pre-erected frame structure.
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BACKGROUND OF THE INVENTION
This invention relates to a device for producing a control signal for feedback control of the air/fuel ratio of an air-fuel mixture supplied to a combustor, such as the combustion chambers of an internal combustion engine, based on the concentration of oxygen in a combustion gas exhausted from the combustor.
In recent internal combustion engines, particularly in automotive engines, there has developed a marked tendency to very minutely control the air/fuel mixing ratio to improve the efficiency of the engines and reduce the emission of noxious components of exhaust gas. In many cases it is desirable to feed an engine with a stoichiometrical air-fuel mixture, and it has become standard practice to perform feedback control of air/fuel mixing ratio with the aim of maintaining a stoichiometric air/fuel ratio by using an exhaust gas sensor which provides a feedback signal indicative of the composition of an air-fuel mixture actually supplied to the engine.
For example, in an automotive engine system using a so-called three-way catalyst which can catalyze both reduction of nitrogen oxides and oxidation of carbon monoxide and unburned hydrocarbons contained in the exhaust gas, it is quite important to always feed the engine with an exactly stoichiometrical air-fuel mixture because this catalyst performs most effectively in an exhaust gas produced by combustion of a stoichiometrical air-fuel mixture. Accordingly, in this engine system it becomes indispensable to perform feedback control of the air/fuel mixing ratio.
Usually, conventional feedback air/fuel ratio control systems aiming at a stoichiometric air/fuel ratio utilize an oxygen sensor that operates on the principle of a concentration cell as an exhaust gas sensor to provide a feedback signal. This type of oxygen sensor has a layer of an oxygen ion conductive solid electrolyte, such as zirconia stabilized with calcia, formed into the shape of a tube closed at one end. A measurement electrode layer is porously formed on the outer side of the solid electrolyte tube and a reference electrode layer is formed on the inner side of the tube. When there is a difference in oxygen partial pressure between the reference electrode side and measurement electrode side of the solid electrolyte layer, this sensor generates an electromotive force between the two electrode layers. As an exhaust gas sensor, the measurement electrode layer is exposed to an engine exhaust gas while the reference electrode layer on the inside is exposed to atmospheric air utilized as the source of a reference oxygen partial pressure. In this environment the magnitude of an electromotive force generated by the oxygen sensor exhibits a large and rapid change between a maximally high level and a minimally low level upon the occurrence of a change in the air/fuel ratio of a mixture fed to the engine across the stoichiometric air/fuel ratio. Accordingly it is possible to produce a fuel feed rate control signal based on the result of a comparison of the output of the oxygen sensor with a reference voltage which is set at the middle of the high and low levels of the sensor output.
However, this type of oxygen sensor has disadvantages such as: significant temperature dependence of its output characteristic: necessity of using a reference gas such as air; difficulty in reducing its size; and poor mechanical strength.
To eliminate these disadvantages, U.S. patent application Ser. No. 12,763 filed Feb. 16, 1979 and now U.S. Pat. No. 4,207,159 discloses an advanced oxygen sensor, which is of a concentration cell type having a flat solid electrolyte layer with reference and measurement electrode layers formed respectively on the two opposite sides thereof and a shield layer formed on the reference electrode side of the solid electrolyte layer so as to cover the reference electrode layer entirely. Either the shield layer or the solid electrolyte layer is made rigid and thick enough to serve as a substrate, and each of the remaining three layers can be formed as a thin film-like layer. This sensor does not use any reference gas. Instead, a DC power supply is connected to this sensor so as to force a current to flow through the solid electrolyte layer between the reference and measurement electrode layers thereby to cause migration of oxygen ions through the solid electrolyte layer in a selected direction and, as a consequence, establish a reference oxygen partial pressure at the interface between the solid electrolyte layer and the reference electrode layer. (The particulars of this oxygen sensor will be described hereinafter.)
When disposed in an engine exhaust gas, this advanced oxygen sensor exhibits an output characteristic generally similar to that of the conventional oxygen sensor having a tubular solid electrolyte. Accordingly, this oxygen sensor is serviceable as a device to provide a feedback signal in an air/fuel ratio control system aiming at a stoichiometric air/fuel ratio. Moreover, this sensor has advantages, such as: lack of need for any reference gas; possibility of making it small in size; and good resistance to shocks and vibrations. However, the output characteristic of this oxygen sensor too is significantly affected by temperature. Particularly, when the temperature of the sensor is below about 500° C. the output characteristic changes such that it becomes difficult to make a comparison between a reference voltage of an adequate level and the output of the sensor. This is a matter of great inconvenience in practical air/fuel ratio control systems for automotive engines.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a device for producing a control signal for feedback control of the air/fuel ratio of an air-fuel mixture supplied to a combustor, such as combustion chambers of an internal combustion engine. The device includes an improved oxygen-sensitive element to be disposed in a combustion gas exhausted from the combustor and which can produce an air/fuel ratio control signal in accordance with the deviation of an actual air/fuel ratio of the air-fuel mixture from a stoichiometric air/fuel ratio with good stability and without being influenced by temperature even when the temperature is considerably low.
A device according to the invention comprises an oxygen-sensitive element which is to be disposed in a combustion gas exhausted from a combustor and comprises first and second concentration cells each composed of: a layer of an oxygen ion conductive solid electrolyte; a measurement electrode layer formed on one side of the solid electrolyte layer; a reference electrode layer formed on the other side of the solid electrolyte layer; and a shield layer formed on the reference electrode side of the solid electrolyte layer such that macroscopically the reference electrode layer is entirely shielded from an environmental atmosphere by the shield layer and the solid electrolyte layer. At least one of the shield layer and the solid electrolyte layer has a microscopically porous and gas permeable structure. The device further comprises DC power supply means for forcing a first DC current of a predetermined intensity to flow through the solid electrolyte layer of the first concentration cell from the reference electrode layer towards the measurement electrode layer and a second DC current of a predetermined intensity to flow through the solid electrolyte layer of the second concentration cell from the measurement electrode layer towards the reference electrode layer. A signal-producing circuit has comparing means for making a comparison between a first output voltage developed between the reference and measurement electrode layers of the first cell and a second output voltage developed between the reference and measurement electrode layers of the second cell to examine which one of the first and second output voltages is higher than the other. Signal-generating means is provided for producing an air/fuel ratio control signal which varies according to a high-low relationship between the first and second output voltages examined by the comparing means.
The flow of a DC current in each cell causes migration of oxygen ions through the solid electrolyte layer between the reference and measurement electrode layers in a direction reversely of the direction of the current flow. As a consequence, in the first cell a reference oxygen pressure of a relatively high magnitude can be maintained on the reference electrode side, whereas in the second cell a reference oxygen partial pressure of a relatively low magnitude can be maintained on the reference electrode side. Therefore, in a combustion gas produced from a fuel-rich air-fuel mixture the first output voltage becomes higher than the second output voltage, but in a combustion gas produced from a lean mixture containing excess air the first output voltage becomes lower than the second output voltage. At a stoichiometric air/fuel ratio, each of the first and second output voltages exhibits a sharp change between a high level and a low level. Since the output characteristics of the first and second cells are similarly influenced by the temperature of the oxygen-sensitive element, a high-low relationship between the first output voltage and the second output voltage remains unchanged even though the temperature of the element varies considerably. Therefore, this device can produce a control signal for feedback control of the air/fuel ratio aiming at a stoichiometric air/fuel ratio with good stability and accuracy even when the combustion gas temperature is considerably low.
In principle, the first and second oxygen concentration cells in the oxygen-sensitive element may be separated from each other, but in practice it is preferred to unite the two cells into a single element by uniting either the shield layers or the solid electrolyte layers of the two cells into a single layer which is made rigid and thick enough to serve as a structurally basic member or substrate of the entire element. The oxygen-sensitive element can be designed in a variety of forms as will be illustrated in the description of the preferred embodiments.
For example, the signal-generating means in the present invention can be composed of a combination of a voltage divider to which a constant source voltage is applied and a switching transistor the base of which is connected to the output terminal of the comparing means.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic and sectional view of a conventional oxygen sensor;
FIG. 2 is a graph showing dependence of oxygen concentration in an exhaust gas discharged from an engine and output voltage of the oxygen sensor of FIG. 1 disposed in the exhaust gas on the air/fuel ratio of an air-fuel mixture supplied to the engine;
FIGS. 3 and 4 show schematically and sectionally a fundamental construction of a recently developed oxygen-sensitive element for the explanation of the principle of the function of the element;
FIG. 5 is a graph showing output characteristics of the oxygen-sensitive element of FIGS. 3 and 4 in an engine exhaust gas;
FIG. 6 is a graph showing the dependence of the electrical resistance of a solid electrolyte layer in the oxygen-sensitive element of FIGS. 3 and 4 on temperature;
FIGS. 7 and 8 are graphs showing the dependence of the output voltage of the oxygen-sensitive element of FIGS. 3 and 4 in an engine exhaust gas on the temperature of the element;
FIG. 9 is a schematic and partly sectional illustration of a control signal producing device as an embodiment of the present invention; and
FIGS. 10-13 show, each in a view similar to FIG. 9, four differently designed devices embodying the present invention, respectively.
DETAILED DESCRIPTION OF THE INVENTION
Prior to a detailed description of preferred embodiments of the present invention, a conventionally popular oxygen sensor will be described briefly, and then an advanced oxygen sensing element according to U.S. Pat. No. 4,207,150 will be described somewhat in detail.
FIG. 1 shows the construction of a conventional oxygen sensor currently used in automobile exhaust systems to detect the air/fuel ratio of air-fuel mixtures supplied to the engines. This oxygen sensor has a layer 10 of an oxygen ion conductive solid electrolyte, such as ZrO 2 stabilized with CaO or Y 2 O 3 , which is formed into the shape of a tube closed at one end. Formed on the outer side of the solid electrolyte tube 10 is a thin and microscopically porous measurement electrode layer 12 which is exposed to an exhaust gas E when the sensor is attached to an exhaust pipe 16 for an automotive engine. Formed on the inner side of the solid electrolyte tube 10 is a thin and microscopically porous reference electrode layer 14 which is isolated from the exhaust gas and exposed to atmospheric air A utilized as the source of a reference oxygen partial pressure. Usually platinum is used as the material for the electrode layers 12 and 14.
The concentration of oxygen in the exhaust gas E depends primarily on the air/fuel ratio of an air-fuel mixture subjected to combustion in the engine and, as represented by curve O 2 in FIG. 2, gradually increases as the air/fuel ratio becomes higher. However, an electromotive force generated across the solid electrolyte layer 10 as output voltage V of the oxygen sensor of FIG. 1 in the exhaust gas is not proportional to the oxygen concentration in the exhaust gas. While a fuel-rich mixture is supplied to the engine, a local oxygen concentration at the surface of the measurement electrode layer 12 becomes almost zero because there occur oxidation reactions of CO, HC (unburned hydrocarbons), etc. contained in the exhaust gas at the surface of the electrode layer 12 which is made of a catalytic material such as platinum, so that a great difference in oxygen partial pressure is produced between the outer and inner sides of the solid electrolyte layer 10. Therefore, the output voltage V of the oxygen sensor remains practically constantly at a maximally high level so long as the air/fuel ratio is below a stoichiometric ratio (about 14.7 for air-gasoline mixture) as represented by curve V in FIG. 2. While a lean mixture is supplied to the engine, a difference in oxygen partial pressure between air A and the exhaust gas E becomes very small, so that the output voltage V of the sensor remains practically constantly at a minimally low level. Therefore, the output voltage of this oxygen sensor in the exhaust gas E exhibits a great and abrupt change as can be seen in FIG. 2 when the air/fuel ratio changes across the stoichiometric ratio. In other words, in the exhaust gas E this oxygen sensor exhibits an on-off type output characteristic with respect to the air/fuel ratio. The output voltage V of this oxygen sensor is affected by the temperature of the sensor, and the characteristic curve V in FIG. 2 represents experimental data obtained at a constant temperature of 600° C.
In conventional air/fuel ratio control systems which utilize an oxygen sensor of the type as shown in FIG. 1 to maintain a stoichiometric air/fuel ratio, the output voltage of the oxygen sensor is used as a feedback signal and compared with a fixed reference voltage which corresponds to the stoichiometric air/fuel ratio (for example, 500 mV in the case of the sensor output characteristic of FIG. 2). While the output voltage is higher than the reference voltage, a judgement that a fuel-rich mixture is being supplied to the engine is made, and accordingly a control signal to decrease the fuel feed rate is produced. While the output voltage of the sensor is below the reference voltage a judgement is made that a lean mixture (containing excess air) is being supplied to the engine, and a control signal to increase the fuel feed rate is produced. In practice, however, this oxygen sensor has disadvantages in several respects as mentioned hereinbefore.
FIG. 3 shows a fundamental construction of an advanced oxygen-sensitive element 20 disclosed in U.S. Pat. No. 4,207,159 and an air/fuel ratio detecting device using the same element. This oxygen-sensitive element 20 has a shield layer 22 which is made of an electrochemically inactive and heat-resistant material and thick enough to serve as a structurally basic member or substrate of the element 20. A reference electrode layer 24, an oxygen ion conductive solid electrolyte layer 26 and a measurement electrode layer 28 are formed on the shield layer 22 one upon another such that the reference electrode layer 24 is sandwiched between the shield layer 22 and the solid electrolyte layer 26 and, macroscopically, entirely shielded from the environmental atmosphere. The measurement electrode layer 28 on the outer side of the solid electrolyte layer 26 is made to have a microscopically porous and gas permeable structure, and at least one of the solid electrolyte layer 26 and the shield layer 22, usually the former, is made to have a microscopically porous and gas permeable structure. It will be understood that the solid electrolyte layer 26 and the two electrode layers 24, 28 constitute an oxygen concentration cell which generates an electromotive force when there is a difference in oxygen partial pressure between the reference electrode side and the measurement electrode side of the solid electrolyte layer 26. In this element 20, it is not intended to introduce a certain reference gas to the surface of the reference electrode layer 24. Instead, a DC power supply 30 is connected to the reference and measurement electrode layers 24 and 28 to force a DC current to flow through the solid electrolyte layer 26 between the two electrode layers 24 and 28 in a selected direction.
In the case of FIG. 3, the DC power supply 30 is connected to the reference and measurement electrode layers 24 and 28 such that a current I 1 flows through the solid electrolyte layer 26 from the reference electrode layer 24 towards the measurement electrode layer 28. When, therefore, this element 20 is disposed in an oxygen-containing gas there occurs ionization of oxygen molecules at the measurement electrode layer 28, and the formed oxygen ions migrate through the solid electrolyte layer 26 towards the reference electrode layer 24. The oxygen ions arriving at the reference electrode layer 24 are converted to oxygen molecules, so that there is a tendency that oxygen accumulates on the reference electrode side of the solid electrolyte layer 26 with a resultant rise in oxygen partial pressure on this side. However, the accumulated oxygen continues to flow out through the porous solid electrolyte layer 26. Therefore, a nearly constant oxygen partial pressure is established at the interface between the reference electrode layer 24 and the solid electrolyte layer 26 after the lapse of a short period of time. Then the concentration cell in the element 20 generates an electromotive force indicative of an oxygen partial pressure at the measurement electrode layer 28 relative to the nearly constant oxygen pressure established at the reference electrode layer 24. An output voltage V 1 attributed to this electromotive force can be measured between the reference and measurement electrode layers 24 and 28.
When this element 20 is disposed in an exhaust gas of an internal combustion engine and supplied with a DC current of an appropriate intensity as shown in FIG. 3, the output voltage V 1 becomes either considerably high or very low in accordance with the engine being fed with a rich mixture or a lean mixture. While a rich mixture is fed to the engine, the supply of oxygen to the reference electrode layer 24 by migration of oxygen ions thereto produces a considerable effect compared with the relatively small inward diffusion of gaseous oxygen contained in the exhaust gas through the porous solid electrolyte layer 24. The magnitude of a constant reference oxygen partial pressure established on the reference electrode side depends on various factors such as the exhaust gas temperature, intensity of the DC current I 1 and the thickness and structure of the solid electrolyte layer 24. By way of example, a reference oxygen partial pressure of 10 0 -10 2 atm is established when the exhaust gas temperature is 600° C. and the current intensity is 3 μA, whereas the oxygen partial pressure in the exhaust gas is 10 -2 -10 -3 atm. Accordingly, while a rich mixture is fed to the engine the output voltage V 1 remains at a considerably high level as represented by curve V 1 (solid line) in FIG. 5. However, when a lean mixture is fed to the engine the effect of the migration of oxygen ions to the reference electrode 24 becomes relatively small compared with inward diffusion of an increased quantity of gaseous oxygen through the solid electrolyte layer 26. As a consequence the difference between the reference oxygen partial pressure on the reference electrode side and the oxygen partial pressure in the exhaust gas becomes very small, so that the output voltage V 1 remains at a very low level as shown in FIG. 5. Accordingly, a great and rapid change occurs in the level of the output voltage V 1 when the air/fuel ratio of a mixture supplied to the engine changes across the stoichiometric ratio. Therefore, the device of FIG. 3 can serve the same function as the conventional oxygen sensor of FIG. 1 in a combustion gas.
FIG. 4 shows another case where the DC power supply 30 is connected to the reference and measurement electrode layers 24 and 28 of the oxygen-sensitive element 20 such that a DC current I 2 flows through the solid electrolyte layer 26 from the measurement electrode layer 28 towards the reference electrode layer 24. In this case, oxygen molecules diffused to the reference electrode layer 24 are ionized at this electrode layer 24, and the formed oxygen ions migrate outwardly through the solid electrolyte layer 26. At the measurement electrode layer 28, the oxygen ions are converted to gaseous oxygen which is liberated into the exterior gas atmosphere. Therefore, there is a tendency toward lowering the oxygen partial pressure on the reference electrode side of the solid electrolyte layer 26. Balanced by inward diffusion of oxygen molecules through the solid electrolyte layer, soon a nearly constant and relatively low oxygen partial pressure is established at the interface between the reference electrode layer 24 and the solid electrolyte layer 26. In an exhaust gas discharged from an internal combustion engine operated with a lean mixture, the magnitude of the thus established reference oxygen partial pressure becomes 10 -20 -10 -22 atm, for example, when the exhaust gas temperature is 600° C. and the intensity of the DC current I 2 is 3 μA. Accordingly output voltage V 2 of the element 20 in this case remains at a considerably high level as represented by curve V 2 (broken line) in FIG. 5. When a rich mixture is supplied to the engine, the output voltage V 2 remains at a very low level as shown in FIG. 5 because ionization of oxygen at the reference electrode layer 24 becomes insignificant by reason of a great decrease in the quantity of gaseous oxygen inwardly diffusing through the solid electrolyte layer 26. Therefore, also in this case a great and rapid change occurs in the level of the output voltage V 2 when the air/fuel ratio of a mixture supplied to the engine changes across the stoichiometric ratio.
Either in the case of FIG. 3 or in the case of FIG. 4, it is desirable that the DC power supply 30 is of a constant current type so that the current I 1 or I 2 forced to flow through the solid electrclyte layer 26 between the two electrode layers 24 and 28 is a constant current.
In the device of either FIG. 3 or FIG. 4, the DC power supply 30 and a voltage measuring instrument (not shown) are both connected between the reference and measurement electrode layers 24 and 28. Accordingly the output voltage V 1 or V 2 of the oxygen-sensitive element 20 becomes the sum of an electromotive force the element 20 generates and a voltage developed across the solid electrolyte layer 26, which has an electrical resistance R, by the flow of the constant current I 1 or I 2 therethrough, that is, a voltage expressed by I 1 ×R or I 2 ×R. The resistance R of the solid electrolyte layer 26 depends significantly on the temperature of the element 20 as shown exemplarily in FIG. 6; the resistance R greatly increases as the temperature of the element 20 lowers. Therefore, the output voltage V 1 or V 2 is significantly affected by the temperature of the element 20. As shown in FIGS. 7 and 8, there is a tendency that the output voltage V 1 or V 2 becomes higher as the temperature lowers, and this tendency becomes very strong when the temperature is below a certain level, for example below about 550° C.
In performing feedback control of air/fuel ratio in an internal combustion engine by using the device of FIG. 3 or FIG. 4, it will be natural to compare the output voltage V 1 or V 2 with a fixed reference voltage V r of 0.5 V if a normal output characteristic of the device of FIG. 3 or 4 is as shown in FIG. 5. FIGS. 7 and 8 show that if the temperature of the oxygen-sensitive element 20 is below 450° C. the output voltage V 1 or V 2 remains above the reference voltage V r whether a rich mixture or a lean mixture is supplied to the engine, meaning that the feedback control of air/fuel ratio becomes impossible. In other words, stable operation of a feedback air/fuel ratio control system including the device of FIG. 3 or 4 is difficult while the temperature of the element 20 or exhaust gas temperature is below, for example, about 550° C.
As mentioned hereinbefore, the present invention solves this problem by making the best use of the essential features of the advanced oxygen-sensitive element.
FIG. 9 shows an air/fuel ratio control signal producing device as an embodiment of the present invention. Essentially this device is constituted of an oxygen-sensitive element 40, a set of DC power supplies 50A and 50B, and a signal-producing circuit 60.
The oxygen-sensitive element 40 has a shield layer 42 which is rigid and thick enough to serve as a substrate of this element 40. On one side of the shield layer 42, a first reference electrode layer 44A, a first oxygen ion conductive solid electrolyte layer 46A and a first measurement electrode layer 48A are formed one upon another such that macroscopically the reference electrode layer 44A is entirely shielded from the environmental atmosphere by the shield layer 42 and the solid electrolyte layer 46A. Each of the three layers 44A, 46A and 48A is a thin film-like layer, and the measurement electrode layer 48A and the solid electrolyte layer 46A are both microscopically porous and gas permeable. On the opposite side of the shield layer 42, a second reference electrode layer 44B, a second oxygen conductive solid electrolyte layer 46B and a second measurement electrode layer 48B are formed one upon another generally symmetrically with the corresponding layers 44A, 46A and 48A on the other side. Macroscopically te second reference electrode layer 44B is entirely shielded from the environmental atmosphere, and the second measurement electrode layer 48B and second solid electrolyte layer 46B are microscopically porous and gas permeable.
Thus, this element 40 can be regarded as a combination of two sets of oxygen concentration cells: that is, one constituted of the first solid electrolyte layer 46A, the first reference and measurement electrode layers 44A, 48A and the shield layer 42; and the other constituted of the second solid electrolyte layer 46B, the second reference and measurement electrode layers 44B, 48B and the shield layer 42 which is utilized by the two cells in common.
A first DC power supply 50A, preferably of a constant current type, is connected to the reference and measurement electrode layers 44A and 48A of the first cell so as to force a DC current I 1 of a predetermined intensity to flow through the first solid electrolyte layer 46A from the reference electrode layer 44A towards the measurement electrode layer 48A. A second DC power supply 50B preferably of a constant current type is connected to the electrode layers 44B and 48B of the second cell so as to force a DC current I 2 of a predetermined intensity to flow through the second solid electrolyte layer 46B from the measurement electrode layer 48B towards the reference electrode layer 44B. Accordingly, when the oxygen-sensitive element 40 is disposed in an oxygen-containing gas such as an engine exhaust gas there occurs ionization of oxygen at the first measurement electrode layer 48A, and the formed oxygen ions migrate through the first solid electrolyte layer 46A towards the first reference electrode layer 44A, whereas in the cell on the opposite side oxygen ions migrate through the second solid electrolyte layer 46B from the reference electrode layer 44B towards the measurement electrode layer 48B.
The circuit 60 has a comparator 62 and a switching transistor 64. The positive input terminal of this comparator 62 is connected to the first reference electrode layer 44A of the oxygen-sensitive element 40 to receive an output voltage V 1 of the first concentration cell, and the negative input terminal of the comparator is connected to the second measurement electrode layer 48B to receive an output voltage V 2 of the second concentration cell. The output terminal of the comparator 62 is connected to the base of the switching transistor 64 via a resistance R 1 . A source voltage V c is applied to the collector of the transistor 64 through a resistance R 2 , and the emitter of this transistor 64 is grounded through a resistance R 3 . When the transistor 64 is conducting, the resistances R 2 and R 3 constitute a voltage divider. Connected to an output terminal of the voltage divider on the emitter side in an output terminal 66 of the circuit 60.
In the device of FIG. 9, the first concentration cell (comprising the first solid electrolyte layer 46A) corresponds to the element 30 in FIG. 3, and the second concentration cell (comprising the second solid electrolyte layer 46B) corresponds to the element 30 in FIG. 4. When the oxygen-sensitive element 40 in FIG. 9 is disposed in an exhaust gas of a gasoline engine the first concentration cell exhibits an output characteristic as represented by curve V 1 in FIG. 5, while the second cell exhibits an output characteristic represented by curve V 2 in FIG. 5. If a rich mixture is supplied to the engine the output voltage V 1 of the first cell becomes far greater than the output voltage V 2 of the second cell, meaning that the comparator 62 receives a greater input at its positive input terminal than at the negative input terminal. Accordingly the comparator 62 provides an output voltage to the base of the switching transistor 64 so that the transistor 64 becomes conducting and provides a control signal S c of a predetermined voltage to the output terminal 66. For example, when the source voltage V c is 12 V, resistance R 2 is 11 kΩ and resistance R 3 is 1 kΩ, the amplitude of the control signal S c becomes 1 V. This control signal S c is supplied to a fuel feed regulating means (not shown) to decrease the fuel feed rate until the stoichiometric air/fuel ratio is realized. If a lean mixture is supplied to the engine the output voltage V 1 of the first cell becomes far lower than the output voltage V 2 of the second cell, meaning that the comparator 62 receives a greater input at its negative input terminal than at the positive input terminal. Accordingly the comparator 62 stops producing an output, so that the transistor 64 becomes nonconducting. Therefore, the control signal S c at the output terminal 66 becomes a zero volt signal, which causes the fuel feed regulating means to increase the fuel feed rate until the stoichiometric air/fuel ratio is realized.
Both of the output voltages V 1 and V 2 depend on the temperature of the oxygen-sensitive element 40, and as the temperature lowers both of these output voltages V 1 and V 2 become similarly higher. Accordingly, a highlow relationship between the two output voltages V 1 and V 2 remains unchanged even though the temperature becomes as low as 450° C. by way of example to cause a great rise of the maximal level of each output voltage V 1 , V 2 , as will be understood by reference to FIGS. 7 and 8. In a feedback control system including the signal-producing device of FIG. 9, it is unnecessary to use a fixed reference voltage corresponding to the reference voltage V r in FIGS. 7 and 8. Thus, by utilizing the device of FIG. 9 it becomes possible to stably perform feedback control of air/fuel ratio, aiming at a stoichiometric ratio, without the control being unfavorably influenced by changes in the temperature of the sensitive element 40 or exhaust gas in which the element 40 is disposed.
FIG. 10 shows another embodiment of the present invention. An oxygen-sensitive element 41 is this signal-producing device is similar in principle to the element 40 in FIG. 9 but different in the arrangement of the two oxygen concentration cells. The combination of the first reference electrode layer 44A, first solid electrolyte layer 46A and first measurement electrode layer 48A is formed so as to occupy a limited portion of the surface area of the shield layer 42. Spaced from this combination, but on the same side of the shield layer 42, the combination of the second reference electrode layer 44B, second solid electrolyte layer 46B and second measurement electrode layer 48B is formed similarly to the first combination of the three layers 44A, 46A and 48A. The shield layer 42 is common to the two concentration cells and serves also as the substrate of the entire element 41.
In other respects, the device of FIG. 10 is constructed identically with the device of FIG. 9. The first DC power supply 50A is connected to the first cell of the oxygen-sensitive element 41 so as to force a constant DC current I 1 to flow through the first solid electrolyte layer 46A from the first reference electrode layer 44A towards the first measurement electrode layer 48A. The second DC power supply 50B is connected to the second cell so as to force a constant current I 2 to flow through the second solid electrolyte layer 46B from the measurement electrode layer 48B towards the reference electrode layer 44B. The output voltage V 1 of the first cell and the output voltage V 2 of the second cell are applied respectively to the positive and negative input terminals of the comparator 62 of the signal-producing circuit 60. Therefore, the function of the device of FIG. 10 with the oxygen-sensitive element 41 disposed in a combustion gas is identical with the function of the device of FIG. 9.
FIG. 11 shows a signal-producing device which is almost identical with the device of FIG. 10. As a sole modification, oxygen-sensitive element 43 in this device has a single solid electrolyte layer 46C which can be regarded as the union of the first and second solid electrolyte layers 46A and 46B in the element 41 of FIG. 10. That is, a part of this solid electrolyte layer 46C intervening between first reference and measurement electrode layers 44A and 48A is utilized to constitute the first concentration cell and another part intervening between the second reference and measurement electrode layers 44B and 48B is utilized to consititute the second cell. Of course, the first and second reference electrode layers 44A and 44B are spaced from each other, and the first and second measurement electrode layers 48A and 48B are spaced from each other. It will be understood that the device of FIG. 11 functions identically with the devices of FIGS. 9 and 10.
FIG. 12 shows a still another embodiment of the invention. An oxygen-sensitive element 45 in this signal-producing device has a single solid electrolyte layer 46 which is in the form of a rigid plate thick enough to serve also as a structurally basic member or substrate of this element 45. On one side of this solid electrolyte layer 46, a thin first reference electrode layer 44A and a thin second reference electrode layer 44B are formed with a distance therebetween. On the same side of the solid electrolyte layer 46, a first shield layer 42A is formed so as to entirely cover the first reference electrode layer 44A, and a second shield layer 42B to entirely cover the second reference electrode layer 44B. On the opposite side of the solid electrolyte layer 46, first measurement electrode layer 48A is formed so as to occupy a limited area and lie generally opposite to the first reference electrode layer 44A. On the same side, second measurement electrode layer 48B is formed so as to be spaced from the first measurement electrode layer 48A and lie generally opposite to the second reference electrode layer 44B. Also in this case the solid electrolyte layer 46 may be made microscopically porous. Alternatively, this solid electrolyte layer 46 may be made to have a tight, dense and practically gas impermeable structure, conditioning that then the first and second shield layers 42A and 42B are made microscopically porous and gas impermeable. When the solid electrolyte layer 46 is gas impermeable but the shield layers 42A, 42B are gas permeable, the reference electrode layers 44A, 44B are also made gas permeable. Thus, this oxygen-sensitive element 45 also comprises two sets of oxygen concentration cells.
Aside from the described difference in design of the oxygen-sensitive element 45, the device of FIG. 12 is constructed identically with the device of FIG. 9 and, therefore, has the same function as the device of FIG. 9.
FIG. 13 shows a modification of the oxygen-sensitive element 45 of FIG. 12. Oxygen-sensitive element 47 of FIG. 13 is made by uniting the first and second shield layers 42A and 42B in FIG. 12 into a single shield layer 42C which covers both the first and second reference electrode layers 44A and 44B. Where the solid electrolyte layer 46 has a gas impermeable structure, this shield layer 42C is made to have a microscopically porous and gas permeable structure. In other respects, the device of FIG. 13 is identical with the device of FIG. 12 in construction and function.
For every one of the oxygen-sensitive elements shown in FIGS. 9-13, it is optional to provide a porous protective coating which covers the first and second measurement electrode layers 48A, 48B if desired together with the outer surfaces of the solid electrolyte layer(s), or even the entire outer surfaces of the element.
The material for each solid electrolyte layer 46, 46A, 46B, 46C can be selected from oxygen ion conductive solid electrolyte materials used for conventional oxygen sensors of the concentration cell type. Some examples are ZrO 2 stabilized with CaO, Y 2 O 3 , SrO, MgO, ThO 2 , WO 3 or Ta 2 O 5 ; Bi 2 O 3 stabilized with Nb 2 O 5 , SrO, WO 3 , Ta 2 O 5 or Y 2 O 3 ; and Y 2 O 3 stabilized with ThO 2 or CaO. In the case of using the solid electrolyte layer 46 as the substrate of the oxygen-sensitive element as in FIGS. 12 and 13, this layer 46 may be produced, for example, by sintering of a press-molded powder material or sintering of a so-called green sheet obtained by molding or extrusion of a wet composition comprising a powdered solid electrolyte material as the principal component. Where the shield layer 46 is used as the substrate of the oxygen-sensitive element, each solid electrolyte layer 46A, 46B, 46C may be formed as a thin film-like layer by a physical deposition technique such as sputtering or ion plating, or by an electrochemical technique typified by plating, or by a process having the steps of printing a paste containing a powdered solid electrolyte material onto the substrate and then firing the paste-applied substrate.
Each shield layer 42, 42A, 42B, 42C is usually made of an electrically insulating ceramic material such as alumina, mullite, spinel or forsterite. When made to serve as the substrate of the oxygen-sensitive element, the shield layer 42 is produced, for example, by sintering of either a green sheet or a press-formed powder material, or by machining of a body of a selected material. Where the solid electrolyte layer 46 is used as the substrate, each shield layer 42A, 42B, 42C may be formed as a relatively thin film-like layer, for example, by a physical deposition technique, by plasma spraying or by the steps of printing a paste containing a powdered ceramic material onto the substrate and then sintering the printed paste layer.
Each of the reference and measurement electrode layers 44A, 44B, 48A, 48B is made of an electronically conductive material selected from electrode materials for conventional solid electrolyte oxygen sensors. Examples are metals of the platinum group, which exhibit a catalytic action on oxidation reactions of hydrocarbons, carbon monoxide, etc., such as Pt, Pd, Ru, Rh, Os and Ir, including alloys of these platinum group metals and alloys of a platinum group metal with a base metal, and some other metals and oxide semiconductors such as Au, Ag, SiC, TiO 2 , CoO and LaCrO 3 which do not catalyze the aforementioned oxidation reactions. Each electrode layer is formed on a shield layer or a solid electrolyte layer as a relatively thin film-like layer, for example, by a physical deposition technique such as sputtering or ion plating, or by an electrochemical technique typified by plating, or by printing of a paste containing a powdered electrode material, followed by firing of the paste-applied shield layer and/or solid electrolyte layer.
For the aforementioned porous protective coating, use may be made of a heat-resistant and electrically insulating material such as alumina, spinel, mullite or calcium zirconate (CaO--ZrO 2 ). The porous protective coating may be produced, for example, by plasma spraying or by the steps of immersing the oxygen-sensing element in a slurry of a selected powder material, drying the slurry adhered to the element and then firing the thus treated element.
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A device comprising an oxygen-sensitive element to be disposed in combustion gas exhausted from a combustor to detect deviation of actual air/fuel mixing ratio of a mixture supplied to the combustor from a stoichiometric ratio. The element is a combination of two oxygen concentration cells each having a solid electrolyte layer, a measurement electrode layer formed on one side of the electrolyte layer and a reference electrode layer formed on the opposite side and covered with a shield layer. The device includes DC power supply means for forcing a current to flow through the solid electrolyte layer of each cell thereby to cause migration of oxygen ions therethrough, from the measurement electrode to the reference electrode in one cell and reversely in the other cell, and a circuit to make a comparison between first and second output voltages respectively developed by the first and second cells to examine which one of these two output voltages is higher than the other and produce a control signal according to the result of the comparison. The signal-producing function is not influenced by the temperature of the element so that a correct control signal can be produced even when the element is not yet sufficiently heated.
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FIELD OF THE INVENTION
This invention relates to the manufacture of nonwoven fibrous mats. More particularly, it relates to a method of forming fiber glass mats containing discrete areas which have different characteristics or properties from the main body of the mat.
BACKGROUND OF THE INVENTION
Nonwoven fiber glass mats are conventionally produced by dispersing glass fibers in chemically treated water to form an aqueous slurry stock, depositing the slurry onto a foraminous forming belt, such as the chain or wire of a Fourdrinier machine, while the belt is moving through a fiber deposition zone, and drawing water from the slurry through the belt to cause a layer of fiber to remain on the belt. The slurry stock is brought to the moving belt in quantities correlated to the speed of the belt to produce a mat comprised of fibers which are oriented in a predetermined manner. For example, if the stock is introduced to the moving wire at a relatively slow rate compared to the speed of the wire, the fibers become oriented in the machine direction. If the stock is introduced at a relatively fast rate compared to the speed of the wire, the fibers are distributed on the wire in random orientation. While both directionally and randomly oriented mats are suited for various types of applications, it would be beneficial in some applications to have a mat which contains separate areas of different character.
U.S. Pat. No. 3,969,561 discloses an air-borne method of forming a nonwoven fibrous mat which involves the use of either impervious bars disposed over a forming screen or impervious areas incorporated into the screen. Fibers are thereby prevented from being deposited on the screen beneath the bars or in the impervious areas of the screen. The impervious bars or screen areas extend throughout the entire fiber deposition zone so that at no point does the stream of fibers encounter an area which is completely unblocked. The dimensions and spacing of the impervious bars or areas are such that fibers falling on them are able to bridge across to the unblocked areas. In that way a mat is formed continuously across the width of the screen, with the fibers in the portions of the mat corresponding to the adjacent blocked and unblocked areas of the screen being at right angles to each other. The method is disclosed in connection with the manufacture of decorative striped fabrics.
U.S. Pat. No. 4,070,235 discloses a method for making a nonwoven fibrous mat from an aqueous slurry by utilizing fluid impervious bars to block portions of a forming screen or by incorporating fluid impervious blocking means into the forming screen. Fibers of different lengths are used to obtain the desired bridging effect. The impervious bars or screen areas extend throughout the entire fiber deposition zone, as in the disclosure of U.S. Pat. No. 3,969,561. The product produced is similar to the product produced by the method of U.S. Pat. No. 3,969,561.
The mats produced by these methods are restricted in design to the configurations made possible by the method of production. It would be desirable to be able to produce nonwoven mats having different and more varied designs incorporated into the body of the mat. It would also be beneficial to be able to produce a mat which has areas of different physical properties so as to be especially suited for certain specific types of installations, making it possible to customize a mat depending on its intended use.
BRIEF SUMMARY OF THE INVENTION
The method of the invention is an improvement to the conventional method of forming a nonwoven fibrous mat of generally random fiber orientation. Typically, such mats are produced by forming an aqueous fibrous slurry, depositing the slurry onto a permeable or foraminous support while the support is moving through a fiber deposition zone, and drawing water from the slurry through the foraminous support to cause a layer of fibers from the slurry to remain on the support. The layer of fibers is dried and removed from the support to form the final mat product. The fibers can be inorganic, such as glass fibers, or organic fibers or mixtures of inorganic and organic fibers.
In accordance with the invention, discrete areas of the permeable support are modified to restrict the flow of water therethrough compared to adjacent areas of the support while still maintaining enough flow to permit the deposition of fibers from the slurry in the discrete areas. This results in a lesser quantity of fiber deposited per unit area of the restricted portions of the permeable support than in adjacent areas. The mat is thus thinner in the discrete areas of the mat than in adjacent areas, and the fibers within the discrete areas may be oriented in a predetermined direction.
The flow of water through the discrete areas of the permeable support may be restricted in varying degree by any suitable means capable of being implemented on the particular permeable support employed. For example, flow may be restricted by coating or pattern printing the wires of a forming screen in the discrete restricted-flow areas with a substance which makes the discrete areas less permeable to water than the untreated areas.
The resulting mat has areas which are different than the rest of the mat. They may provide a decorative effect or they may have improved physical properties particularly suitable for certain service requirements. In addition, the method of the invention is simple and economical to implement in commercial manufacturing operations.
The above and other aspects and benefits of the invention will readily be apparent from the more detailed description of the preferred embodiments of the invention which follows.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a schematic representation of a nonwoven mat forming operation adapted to carry out the present invention;
FIG. 2 is an enlarged plan view of a portion of an illustrative forming screen or wire which can be used in carrying out the invention;
FIG. 3 is an enlarged plan view of a portion of a fibrous mat formed through use of the forming screen of FIG. 2;
FIG. 4 is an enlarged transverse sectional view taken on line 4--4 of FIG. 3;
FIG. 5 is an enlarged plan view of a portion of another illustrative forming screen which can be used in carrying out the invention;
FIG. 6 is an enlarged plan view of a portion of a fibrous mat formed through use of the forming screen of FIG. 5;
FIG. 7 is an enlarged plan view of a portion of a fibrous mat formed with another modified forming screen; and
FIG. 8 is an enlarged plan view of a portion of a forming screen which has been coated with a substance to make the screen more restrictive to the flow of water.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
As previously mentioned, nonwoven fibrous mats are typically formed by means of a so-called wet operation in which a fibrous slurry is deposited on a moving screen. A typical screen is comprised of polyester and/or nylon monofilaments or "wires" woven in an open weave. Such an operation is schematically illustrated in FIG. 1, wherein a headbox 10 receives an aqueous fibrous slurry which has been mixed in the tank 12. The slurry consists of fibers, such as glass fibers, water and chemicals which have been added to the water to aid in the dispersal of the fibers. The particular mixer employed and the specific chemicals added to the water are not described herein since these aspects of the method are well known in the art, as disclosed in U.S. Pat. No. 4,112,174, which patent is herein incorporated by reference. This invention can also be practiced on the well known cylinder machine process.
An endless forming screen 14 travels about a path defined by a number of rolls, which have been shown for purposes of illustration as comprising larger rolls 16, 18 and 20 and smaller guide rolls 22 and 24. One of the larger rolls is mounted on a powered shaft and drives the screen. The screen moves through the end of the headbox 10 where it is exposed to the slurry. A series of vacuum boxes 26 located beneath the moving screen in the area of the headbox assists in drawing water from the slurry through the screen, leaving a wet layer or mat M of fibers on the moving screen. The mat is then transferred from the moving screen 14 to a conveyor 28, which transports the mat through a binder application station 30 and a drying oven 32. The final mat product exits from the drier and may be subjected to further operations, which do not form part of the present invention, such as being cut or trimmed to size or combined with other elements in the manufacture of a final product incorporating the mat as an element.
A forming screen of the type conventionally employed in the manufacture of wet-laid fibrous products is a woven wire mesh screen which is sufficiently flexible to be trained about its guide rolls. As is well known in the art, the wires are spaced to allow water in a fibrous slurry fed to the screen to drain through the screen while retaining the fibers on the upper surface of the screen.
In accordance with the invention, discrete areas of the screen are formed or treated so as to restrict drainage through those areas compared to the drainage through adjacent untreated areas. As shown in FIG. 2, the screen 14 contains areas 34 which are slower draining than the main body of the screen. As noted above, when a fibrous slurry stock is introduced to the moving screen or wire at a relatively slow rate compared to the speed of the wire, the fibers become oriented in the machine direction, and when the stock is introduced at a relatively fast rate compared to the speed of the wire, the fibers are distributed on the wire in random orientation. The slower draining areas of the screen result in a lesser quantity of fibers being collected on the screen in those areas. This in turn causes the fibers in areas of the mat corresponding to the reduced drainage areas of the forming screen to be slightly more aligned in the machine direction.
The fiber deposition on the screen between the slower draining areas will be much greater than on the screen in the slower draining areas. When the slower draining areas are relatively close together, the fiber deposition in the narrow regions between them will be locally oriented, i.e.,the fibers will tend to lie generally parallel to the adjacent sides of the discrete areas and be generally aligned in the machine direction, while the fibers corresponding to the untreated areas of the forming screen are more randomly oriented. The fibers within a slow draining area are indicated in FIG. 3 as the fibers 36, while the fibers in the untreated areas of the screen are indicated at 38. As illustrated in FIG. 4, the areas of the mat corresponding to the areas of reduced drainage on the forming screen are of less thickness than the main body of the mat as a result of the lesser amount of fiber retention in those areas.
While the invention may be utilized to produce a mat having areas of different appearance in order to provide a variety of decorative effects, as illustrated by the pattern of restricted drainage of FIG. 2, the physical properties of a mat may also be modified. As shown in FIG. 5, the forming screen 14 has been provided with elongated areas 40 of restricted drainage to produce the alignment of fibers 42 illustrated in the mat of FIG. 6. As compared with the random arrangement of fibers 44 in the mat, the fibers 42 are aligned in the machine direction. The aligned fibers 42 would thus provide greater resistance to tearing when the mat is subjected to forces in the direction perpendicular to fibers 42. It will be appreciated that the areas of restricted drainage in the mat can extend in the machine direction as well, resulting in a mat having areas of fiber alignment as illustrated in FIG. 7, wherein the fibers 46 are aligned in the direction of the elongated areas. Such a mat provides additional tensile strength in the machine direction of the mat.
FIG. 8 illustrates a method of creating areas of restricted flow in a forming screen by employing a coating substance. The screen is illustrated in simplified form as being comprised of woven wires 50 and 52, to which a coating 54 has been applied in the desired area of restricted drainage. The coating may be comprised of any material which has the ability to adhere to the screen wire without completely sealing off the spaces between the wires. The coating material has been applied to the screen in an amount which coats the wires, leaving openings 56 of reduced size between the coated wires. The size of the openings can be controlled through selection of the coating material and the thickness of the coating layer. An example of a coating material of this type is an epoxy, vinyl plastisol or urethane based coating such as commercially available epoxy based paints. The coating should not be affected by the white water of the forming operation, it should adhere well to the forming wire and it preferably should be tough and flexible.
The method of restricting flow is not limited to use of a coating material. For example, flow may be restricted by flattening the wires in selected areas to make them wider and thus spaced closer together. Other methods of restricting flow which have not been illustrated include fusing wires together and selectively changing the weave, warp or shute wires of the screen in the areas of restricted flow. The latter method could include utilizing larger diameter wires in these areas or employing a tighter weave. The use of coating material to restrict flow is preferred due to its simplicity and the ability to control the degree of flow through selection of materials or the application of the coating material in different thicknesses.
It will be appreciated that the invention provides a simple, effective and economical method of manufacturing a nonwoven fibrous mat containing areas of lesser thickness and, if desired, areas in which the fibers are more directionally aligned than in the main body of the mat. This enables mats to be formed with a variety of different designs. By providing for areas in a mat which contain directionally oriented fibers aligned in a direction related to the intended application of the product, certain physical properties of the mat, such as the tensile strength or tear strength, may be enhanced.
It should now be apparent that the invention is not necessarily limited to all the specific details described in connection with the preferred embodiments, but that changes to certain features of the preferred embodiments which do not alter the overall basic function and concept of the invention may be made without departing from the spirit and scope of the invention defined in the appended claims.
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A method of producing a nonwoven fiber glass mat that contains discrete areas which are of different construction than the remainder of the mat. The permeable forming screen onto which a fibrous aqueous slurry is deposited is of a different structure in areas corresponding to the discrete areas of the mat so as to restrict the flow of water through those areas. Less fiber is deposited in those areas, resulting in the discrete areas being comprised of a thinner mat. The orientation of fibers within the discrete areas can be controlled by correlating the restricted flow of slurry in these areas to the flow of slurry necessary to cause this condition.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an improved continuous flow chemical reaction apparatus wherein the introduction of at least one reactant feed into the reaction zone is optimized. The invention also relates to improved chemical reactions achieved using the continuous flow chemical reaction apparatus.
[0003] 2. Description of Related Art
[0004] Several publications are referenced in this application. The references describe the state of the art to which this invention pertains, and are hereby incorporated by reference.
[0005] An oxidative dehydrogenation, or partial oxidation, process is a one step conversion of light hydrocarbons to olefins and carboxylic acids. The process potentially offers many advantages over cracking and pure dehydrogenation which are extremely capital intensive and energy intensive. The conversion of saturated hydrocarbons into olefins and carboxylic acids over low temperature catalysts was disclosed by Thorstienson et al. in a report published in Journal of Catalysis, vol. 52, pp. 116-132 (1978).
[0006] U.S. Pat. No. 4,250,346 discloses a process for oxidative dehydrogenation of ethane to ethylene suggesting different low temperature catalyst systems. European Patent No. EP 0 518 548 A2 discloses a process for making acetic acid which comprises oxidizing ethane with molecular oxygen in a reaction zone at a pressure at least 100 psig while the reactants are in contact with a solid catalyst containing vanadium and phosphorous oxides (VPO system).
[0007] The oxidative dehydrogenation reaction, however, raises problems such as: (a) removal of the exothermic heat of reaction, (b) possible associated temperature runaway, (c) control of selectivity to desired product, and (d) limiting the formation of undesired oxygenated by-products and carbon oxides.
[0008] Another problem which is associated with oxydehydrogenation processes, as well as oxidation processes, is the limitation on the oxidant to hydrocarbon feed ratios which is imposed by the explosive mixture formation constraint. This problem compromises the ability of the process to achieve optimality of feed compositions that satisfy the stoichiometric and kinetic requirements of the reaction, yet avoid compositions which can lead to autoignition, deflagration, and detonation.
[0009] These problems have been addressed in a number of patents. Each tried to overcome one or more of the difficulties mentioned above by proposing a modified reactor system or different reactor arrangement.
[0010] U.S. Pat. No. 4,899,003 issued to Union Carbide relates to multi-staging the reactor system where a feed gas comprising ethane and oxygen is converted over an oxydehydrogenation catalyst to a product gas comprising ethylene, acetic acid, water, ethane, and carbon oxides. The product gas from each stage (other than the last stage) is cooled and a portion of the acetic acid and water is separated and oxygen is added before passing the product gas stream to the next reaction stage. Total oxygen content in the feed stream to any of the reactors was maintained below 6 mole percent with respect to the total input gaseous stream in that stage.
[0011] U.S. Pat. No. 5,583,240 issued to SRI relates to a reactor with porous membranes to provide for the continuous addition of one reactant all along the reactor and mixing in the entire volume of the reactor to minimize or eliminate local high concentration gradients and hot spots. The other reactant is flowed through the inside of the permeation tube, which contains mixing elements. Those mixing elements were claimed to increase the yield of desired product by increasing the heat and mass transfer rates.
[0012] European Patent No. EP 546 677 A1 relates to a fluidized bed for ethane oxidation to acetic acid. The disclosed process included three key steps: (1) cooling the gaseous effluent from the reaction zone; (2) separating most of the acetic acid in liquid form from the effluent gases, leaving a gaseous stream containing nearly all of the carbon oxide contained in the effluent; (3) purging a small portion of said gaseous stream and recycling most of the gaseous stream as part of the feed to the reaction zone. Purging is intended to prevent build-up of carbon oxides in the reaction zone, while recycling serves to maintain a high proportion of carbon oxides in the reaction zone gases, thus aiding in moderating the temperature elevating effect of the highly exothermic oxidation reaction.
[0013] U.S. Pat. No. 5,723,094 relates to a chemical reactor design which provides improved micro-mixing conditions and reduced localized zones of concentration to increase reaction selectivity to desired products. The design includes a capillary tubelet positioned within and along the length of flow tubes positioned in a shell reactor and one or more distributors for distributing a first reactant into the flow tubes and a second reactant into the capillary tubes.
[0014] European Patent Publication No. 0 532 325 relates to a method and apparatus for the production of ethylene oxide. European Patent Publication No. 0 383 224 relates to a shell-and-tube reactor and method of using the same.
[0015] It would be desirable to provide a continuous flow chemical reaction system which provides optimality of feed compositions along a substantial portion of the reaction zone and satisfies the stoichiometric and kinetics requirements of the reaction while maintaining the reaction mixture within the explosive mixture formation constraint and thus avoid reactant mixtures which can lead to autoignition, deflagration, and detonation.
OBJECTS OF THE INVENTION
[0016] It is an object of the invention to overcome the above-identified deficiencies.
[0017] It is another object of the invention to provide an improved continuous flow chemical reaction apparatus and method of using the same.
[0018] It is another object of the invention to provide an improved continuous flow chemical reaction system where a controlled amount of at least one fluid reactant is introduced into the reaction zone at more than one location.
[0019] It is another object of the invention to provide an improved continuous flow chemical reaction where a controlled, optimized amount of at least one fluid reactant is introduced into the reaction zone at more than one location.
[0020] It is a further object of the invention to provide an improved continuous flow chemical system for performing a catalytic reaction where at least one fluid reactant is introduced into the reaction zone at more than one location.
[0021] It is a still further object of the invention to provide an apparatus in which one or more of the reactants is fed in an optimized distributed fashion to meet certain safety and performance requirements.
[0022] It is yet another object of the invention to provide a reactor which achieves a catalyst bed temperature profile controlled by means of non-uniform reactant(s) distribution so that desired operating temperature range is achieved along the entire length of the reactor tube.
[0023] It is a still further object of the invention to provide an improved continuous flow chemical reaction system which provides optimality of reacting mixture compositions along a substantial portion of the reaction zone and satisfies the stoichiometric and kinetics requirements of the reaction.
[0024] It is a still further object of the invention to provide a reactor and reaction process wherein the total overall inventory of the reacting mixture falls within an unsafe/explosive composition region, while at any given point or region within the reactor the compositional mixture is within the domain of safe/non-explosive compositions.
[0025] The foregoing and other objects and advantages of the invention will be set forth in or apparent from the following description.
SUMMARY OF THE INVENTION
[0026] The present invention relates to a process and apparatus for the controlled/optimized addition of reactant(s) in continuous flow chemical reactions, preferably oxidative dehydrogenation, partial oxidation, or oxidation reactions. More specifically, the invention deals with the shortcomings of these high potential processes by the controlled addition of a reactant which is achieved by means of an injection member (tube) along the length of the reaction zone. The injection member (tube) is provided with injector(s) capable of introducing a controlled amount of reactant at the injector site into the reaction zone. Preferably, the injection member (tube) is provided with wall penetrations, holes, perforations, spargers, capable of performing two functions: (1) pressure drop control and (2) flow control. According to one preferred embodiment, the injectors allow for the introduction of a controlled amount of reactant into the reaction zone without allowing any reactant(s) to flow into the injector member (tube) from the reaction zone.
[0027] The present design offers a high degree of controllability over the quantity of reactant injection and the locations of the points of injection by adjusting the distance between the injection points. Therefore, injection can be optimized in such a way that only the sufficient and kinetically required amount of reactant is supplied at each point and this is controlled to respond to the spatial variation of the reaction conditions (i.e., temperature, pressure and reaction mixture composition).
[0028] According to another embodiment, an intermediate or co-feed may be injected which enhances catalyst performance or suppresses a certain poisoning effect. This provides yet another utility of the present invention.
[0029] The benefits achievable by using the present invention include the accurate control of the temperature profile along the catalyst bed by controlling the reaction extent and heat release via the quantitative and positional control of reactant addition.
[0030] The invention also enhances the catalyst productivity by introducing reactants in proportions which are not possible in conventional reactors due to the explosion regime limitation and the reaction runaway limitation.
[0031] The invention also provides a tool for designing the reaction in such a way that the production of the desired product is optimized.
[0032] The invention also allows for the adjustment of the reactant mixture composition at every point inside the reactor, as well as the reactor entrance, so that reactant mixtures within the explosion regimes can be avoided.
[0033] Furthermore, the invention improves catalyst performance by the delayed addition of a component which reverts its reduction/oxidation state or a component which remedies a catalyst poisoning situation.
BRIEF DESCRIPTION OF THE FIGURES
[0034] The following detailed description, given by way of example but not intended to limit the invention solely to the specific embodiments described, may best be understood in conjunction with the accompanying drawings in which:
[0035] FIG. 1 is a schematical representation of an improved reaction zone according to one embodiment of the invention.
[0036] FIG. 2 is a schematical representation of an improved reaction zone according to another embodiment of the invention.
[0037] FIG. 3 is a schematical drawing of a reaction system according to one embodiment of the invention.
[0038] FIG. 4 is a schematical drawing of a reaction system according to another embodiment of the invention.
[0039] FIG. 5 is a schematical drawing of a reaction system according to yet another embodiment of the invention.
[0040] FIG. 6 is an enlarged schematical drawing of the pressure drop control means shown in FIG. 5 .
[0041] FIG. 7 is a schematical drawing of a reaction system according to another embodiment of the invention.
[0042] FIG. 8 is a schematical drawing of a reaction system according to yet another embodiment of the invention.
[0043] FIG. 9 is a schematical drawing of a reaction system according to another embodiment of the invention.
[0044] FIG. 10 is a graphical representation of the oxygen distribution pattern for a continuous flow chemical reaction zone according to one embodiment of the invention where the vertical axis represents oxygen flow (SLPH) and the horizontal axis represents the reaction tube coordinate along the length of the reaction zone (m).
[0045] FIG. 11 is a graphical representation of the reaction temperature profile for a continuous flow chemical reaction zone according to one embodiment of the invention and according to two comparative continuous flow chemical reaction zones where the vertical axis represents reaction temperature (° C.) and the horizontal axis represents the reaction tube coordinate along the length of the reaction zone (m).
[0046] FIG. 12 is a graphical representation of the oxygen concentration profile for a continuous flow chemical reaction zone according to one embodiment of the invention and according to two comparative continuous flow chemical reaction zones where the vertical axis represents oxygen concentration (mole %) and the horizontal axis represents the reaction tube coordinate along the length of the reaction zone (m).
[0047] FIG. 13 is a schematical drawing of a reaction system according to another embodiment of the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0048] One aspect of the invention relates to improved continuous flow reaction systems.
[0049] One preferred embodiment of the invention relates to multi-tubular fixed bed catalytic reactors with the novel feature of a non-uniform distribution member such as the one described in FIG. 1 . The first reactant feed is fed into a reaction zone via an inlet at one end of the reaction zone, while the second reactant feed is introduced into the reaction zone at a multiplicity of points along the length of the reaction zone via a central tube or distribution member. The distribution member preferably satisfies two important criteria at each point along the length of the catalyst bed: (1) pressure drop control; and (2) flow control.
[0050] Another embodiment of the invention is depicted in FIG. 2 which shows a continuous flow chemical reaction apparatus 10 comprising a reaction zone 11 , preferably a tubular reaction which optionally contains catalyst 12 . Reaction zone 11 also having a length and having a first fluid reactant feed inlet 13 for introducing first fluid reactant feed 14 into tubular reaction zone 11 at a first end 17 and a product outlet 15 for product stream 16 at a second end 18 . The first fluid reactant feed 14 comprises the first fluid reactant and, preferably, a portion of second fluid reactant. The tubular reaction zone 11 also includes an interior conduit 20 extending lengthwise within tubular reaction zone 10 . Conduit 20 having a second feed inlet 21 for introducing a second fluid reactant feed (e.g., containing a second fluid reactant) into tubular reaction zone 11 and, optionally, a second fluid feed outlet 23 for second fluid reactant exit stream 25 . Conduit 20 also having a multiplicity of injectors 30 spaced apart along the length of conduit 20 , each of injectors 30 capable of introducing a controlled amount of a second fluid feed into tubular reaction zone 11 . As shown in FIG. 2 , conduit 20 may pass through the entire length of tubular reaction zone 11 . Alternatively, conduit 20 may end within tubular reaction zone 11 (see FIG. 3 described below).
[0051] According to one embodiment, the second fluid reactant is advantageously mixed with the first fluid reactant in the first fluid feed 14 so that an injector 30 is not required in the first segment of reaction zone 11 . The composition containing the second reactant provided in the first fluid feed may be the same or different from the composition containing the second reactant provided by the second feed. For example, the first feed may include pure oxygen (which is an oxygen-containing composition) as the second reactant and the second feed may contain air (which is also an oxygen-containing composition) also as the second reactant. Alternatively, the first and second feed may contain the same second reactant composition such as each containing air or pure oxygen.
[0052] According to another embodiment, first fluid reactant feed 14 includes the first reactant (without any second reactant) and second fluid reactant feed 22 includes the second reactant. According to this embodiment, the apparatus preferably includes an injector 30 proximate the first end 17 of the reaction zone 11 to provide second reactant at the front end of the reaction zone.
[0053] Yet another embodiment of the invention, depicted in FIG. 3 , relates to a continuous flow chemical reaction apparatus 40 comprising a plurality of tubular reaction zones 11 , optionally containing catalyst 12 , within a heat transfer vessel 41 including at least one heat transfer zone 42 , each of the heat transfer zones 42 having a heat transfer fluid inlet 43 and a heat transfer fluid outlet 44 . Reactor apparatus 40 also having a first reaction feed inlet 45 for first reaction feed 14 . Reactor apparatus 40 also having a second reaction feed inlet 47 for a second reaction feed 22 and a reactor product outlet 46 for product stream 16 . According to one embodiment, first reaction feed 14 contains a first reactant (e.g., ethane, ethylene) and preferably a portion of a second reactant (e.g., air, oxygen). Each of tubular reaction zones 11 having a length, a first fluid reactant feed inlet 13 at a first end, a product outlet 15 at a second end and an interior conduit 20 extending lengthwise within tubular reaction zone 11 . Interior conduits 20 having a multiplicity of injectors 30 spaced apart along the length of the conduits 20 and along the length of the tubular reaction zone 11 and each of injectors 30 being adapted to introduce a controlled amount of second fluid reaction feed 22 into tubular reaction zones 11 .
[0054] Preferably, as depicted in FIG. 4 , heat transfer vessel 41 comprises a plurality of heat transfer zones 42 . According to one preferred embodiment, heat transfer vessel 41 is a cylindrical vessel.
[0055] In another preferred embodiment, depicted in FIG. 5 , the continuous flow chemical reaction apparatus 40 of FIG. 3 has interior conduits 20 which do not dead end in tubular reactor zone 11 but rather extend through tubular reaction zone 11 to outlet header 48 to exit the reaction apparatus 40 through second reactant feed outlet 49 . In this embodiment of the invention, second feed exit stream 25 (containing excess, unreacted second reactant) can be passed through reaction apparatus 40 and thereby assist in removing the heat of reaction. Preferably, second feed exit stream 25 is recycled into reaction zone 11 via inlet 47 .
[0056] Preferably, the apparatus further comprises a catalyst 12 within the tubular reaction zone(s) 11 . Advantageously, the apparatus further comprises a catalyst bed(s) within the tubular reaction zone(s) and surrounding the interior conduit(s).
[0057] According to one preferred embodiment, interior conduit(s) 20 is concentric with the tubular reaction zone(s) 11 . Preferably, the tubular reaction zone(s) 11 has a cross-section which is a substantially circular, interior conduit 20 is concentric with tubular reaction zone 11 and tubular reaction zone 11 comprises a catalyst bed 12 surrounding the interior conduit 20 .
[0058] The apparatus of the invention comprises a plurality of injectors 30 , preferably between 2 and 40 injectors, more preferably between 4 and 25 injectors and most preferred between 6 and 15 injectors. Advantageously, injectors 30 are selected from the group consisting of wall penetrations, holes, perforations, spargers, or combinations thereof.
[0059] According to another preferred embodiment, also depicted in FIG. 5 , the apparatus further comprises a pressure drop control means 50 in conduit(s) 20 proximate to at least one of or each of injectors 30 . Pressure drop control means 50 can be packing, pellets or any other flow restricting devices. FIG. 6 illustrates an enlarged schematical representation of a pressure drop control means 50 (pellets) according to one embodiment of the invention.
[0060] Another embodiment of the invention relates to a continuous flow chemical reaction fluidized bed apparatus 60 as shown in FIG. 7 . Apparatus 60 comprises a fluidized bed reaction zone 55 having a height and having a first fluid reaction feed inlet 13 at a lower end for first fluid reaction feed 14 and a product outlet 15 for product stream 16 at an upper end. The first fluid reaction feed 14 includes a first reactant and preferably a portion of second fluid reactant. Fluidized bed reaction zone 55 also includes an interior conduit 20 extending vertically within the fluidized bed reaction zone 55 , the conduit 20 having a multiplicity of injectors 30 spaced apart along the length of the conduit, each of the injectors 30 capable of introducing a controlled amount of a second fluid reaction feed 22 into the fluidized bed reaction zone 55 . Preferably, conduit 20 also includes pressure drop control means 50 proximate injectors 30 . Second fluid reaction feed 22 preferably comprises a second reactant.
[0061] Yet another embodiment of the invention, shown in FIG. 8 , relates to a continuous flow chemical reaction apparatus 70 comprising a plurality of fluidized bed reaction zones 55 within a heat transfer vessel 41 having at least one heat transfer zone 42 , each of the heat transfer zones 42 having a heat transfer fluid inlet 43 and a heat transfer fluid outlet 44 and each of the tubular reaction zones 55 having a height. The tubular reaction zones 55 also having a first fluid feed inlet 45 for first fluid feed 14 at a lower end, a product feed outlet 46 for product feed 16 at an upper end and an interior conduit 20 extending vertically within each of fluidized bed reaction zones 55 . The interior conduits 20 having a multiplicity of injectors 30 spaced apart along the length of the fluidized bed reaction zones 55 and each of the injectors 30 being adapted to introduce a controlled amount of a portion of second fluid feed reactant 22 into the fluidized bed reaction zone 55 .
[0062] FIG. 9 illustrates a partial schematical view of another embodiment of the invention where apparatus where second reactant feed 22 is introduced into a fluidized bed reaction zone 81 via conduits 82 , wherein the conduits 82 are perpendicular to the flow of first reaction feed 14 and each conduit 82 introduces different or the same amounts of second reaction feed 22 at each point along reaction zone 81 .
[0063] Preferably, the fluidized bed apparatus is capable of operating in the bubbling regime. According to one embodiment, the reaction zone is a circulating fluidized bed.
[0064] Another aspect of the invention relates to improved chemical reactions. Using the present invention, chemical reactions can be performed achieving improved yields and selectivity. The fluid flowing through the distribution member can be a single reactant component, a mixture of reacting components or a mixture of reacting component(s) and inert component(s).
[0065] One embodiment of the invention relates to a method of performing a continuous chemical reaction between at least one first fluid reactant and at least one second fluid reactant to form a reaction product comprising:
[0066] (a) continuously introducing a first fluid reaction feed containing the first reactant and, preferably, the second fluid reactant, into a first end of a tubular reaction zone having a length whereby the first and second fluid reactants continuously flow towards a second end of the tubular reaction zone; and
[0067] (b) continuously introducing a second fluid reaction feed containing the second fluid phase reactant into an interior conduit which extends lengthwise within the tubular reaction zone, the interior conduit having a multiplicity of injectors spaced apart lengthwise along the conduit;
[0068] (c) introducing the second fluid reaction feed into the tubular reaction zone at a multiplicity of points along the length of the tubular reaction zone by passing controlled amounts of the second reaction feed containing the second reactant through the multiplicity of injectors into the tubular reaction zone; and
[0069] (d) providing conditions conducive to the chemical reaction in the tubular reaction zone whereby the chemical reaction proceeds and the reaction product is formed.
[0070] Another embodiment of the invention relates to a method of performing a catalytic chemical reaction comprising reacting a first fluid reactant with a second fluid reactant to form a reaction product in a catalyst bed, wherein
[0071] (a) a first fluid reaction feed is introduced into a first end of a tubular reaction zone having a length and containing the catalyst bed, the first fluid reaction feed containing the first and second fluid reactants flowing towards a second end of the tubular reaction zone;
[0072] (b) a second fluid reaction feed containing the second reactant is introduced into a conduit within and concentric to the tubular reaction zone, the conduit having a multiplicity of injectors spaced apart lengthwise along it and each of the injectors introduces a controlled amount of the second reactant into the tubular reaction zone; and
[0073] (c) providing conditions conducive to the chemical reaction within the tubular reaction zone whereby the chemical reaction proceeds and the reaction product is formed.
[0074] Preferably, the tubular reaction zone(s) contains a catalyst and the first fluid reactant flows through the catalyst along with the second fluid reactant.
[0075] According to one preferred embodiment, the chemical reaction has a selected reaction temperature and the temperature in the tubular reaction zone(s) is maintained within 15° C. of the selected reaction temperature through at least 50% of the length of the tubular reaction zone(s). Preferably, the reaction temperature is maintained within 10° C., advantageously within 6° C. of the selected reaction temperature through at least 50% of the length of the tubular reaction zone(s).
[0076] According to another preferred embodiment, the chemical reaction has an explosive regime when the concentration of the second fluid reactant in the tubular reaction zone is at an explosive concentration and the invention further comprises controlling the amount of the second fluid reactant introduced into the tubular reaction zone so that the concentration of the second fluid reactant is at least 70%, preferably at least 80%, more preferably at least 90%, of the explosive concentration through at least 50% of the length of the tubular reaction zone and does not exceed the explosive concentration at any point throughout the length of the tubular reaction zone.
[0077] According to one preferred embodiment, the total overall inventory of the reacting mixture falls within an unsafe/explosive composition region, while at any given point or region within the reactor the compositional mixture is within the domain of safe/non-explosive compositions.
[0078] According to one embodiment, the chemical reaction is the partial oxidation of ethane to ethylene and acetic acid, and wherein the first fluid reactant comprises ethane and the second fluid reactant comprises oxygen. (e.g., pure O 2 , air, etc.).
[0079] According to another embodiment, the chemical reaction is the partial oxidation of ethane to ethylene and acetic acid, wherein the first fluid reactant comprises ethane and the second fluid reactant comprises oxygen, and at least 10% of the ethane in the first fluid reactant is reacted to form acetic acid per single pass through the tubular reaction zone.
[0080] Another embodiment of the invention relates to a method of performing a continuous chemical reaction in a fluidized bed between at least one first fluid reactant and at least one second fluid reactant to form a reaction product comprising:
[0081] (a) continuously introducing the first fluid reactant and preferably a portion of the second fluid reactant into a lower end of a fluidized bed reaction zone having a height whereby the reactant(s) continuously flows towards an upper end of the fluidized bed reaction zone; and
[0082] (b) continuously introducing the second fluid phase reactant into an interior conduit which extends vertically within the fluidized bed reaction zone, the interior conduit having a multiplicity of injectors spaced apart lengthwise along the conduit;
[0083] (c) introducing the second fluid phase reactant into the first fluid phase reactant at a multiplicity of points along the height of the fluidized bed reaction zone by passing controlled amounts of the second reactant through the multiplicity of injectors into the fluidized bed reaction zone; and
[0084] (d) providing conditions conducive to the chemical reaction in the fluidized bed reaction zone whereby the chemical reaction proceeds and the reaction product is formed.
[0085] Another embodiment relates to a method of performing a catalytic chemical reaction comprising reacting a first fluid reactant with a second fluid reactant to form a reaction product in a catalyst bed, wherein:
[0086] (a) the first fluid reactant, along with a portion of second fluid reactant, is introduced into a lower end of a fluidized bed reaction zone having a height and containing the catalyst bed, the first and second fluid reactants flowing towards an upper end of the fluidized bed reaction zone;
[0087] (b) the second fluid reactant is introduced into a conduit within the fluidized bed reaction zone, the conduit having a multiplicity of injectors spaced apart lengthwise along it and each of the injectors introduces a controlled amount of the second reactant into the fluidized bed reaction zone; and
[0088] (c) providing conditions conducive to the chemical reaction within the fluidized bed reaction zone whereby the chemical reaction proceeds and the reaction product is formed.
[0089] Preferably, the chemical reaction in the fluidized bed proceeds in the bubbling regime.
[0090] A full range of industrially important reactions can benefit from the current inventions especially those suffering from: temperature run-away limitations and explosive mixtures composition limitation such as ethylene oxide, maleic anhydride, phalic anhydride, etc.
[0091] Additional reactions which may be performed using the present invention are set forth in Table I below.
TABLE I Reaction Catalyst Hydrogenation Cyclopropane + H 2 C 3 H 8 C 2 H 6 + Pt, Pd, Rh, Ru H 2 2CH 4 3H 2 + N 2 2NH 3 Fe 2H 2 + COCH 3 OH Cu + /ZnO Heptane toluene + 4H 2 Pt Acetone + H 2 2-propanol Pt, Copper chromite H 2 + aldehyde alcohol Pt, Pd, Rh, Ru Oxi-chlorination Halogenation Oxidation CH 3 OH + ½O 2 CH 2 O + H 2 O Fe 2 O 3 .MoO 3 H 2 O + COH 2 + CO 2 Fe 3 O 4 , Ni, CuO/ZnO ½O 2 + CH 2 CH 2 CH 3 CHO PdCl and similar salts of noble metals RCH 2 OHRCHO + H 2 Pt Glucose d-glucuronic acid Pt
EXAMPLES
[0092] The invention is further described in the following examples. The examples are illustrative of some of the products and methods of making the same falling within the scope of the present invention. They are, of course, not to be considered in any way limitative of the invention. Numerous changes and modifications can be made with respect to the invention.
Example 1
[0093] Partial oxidation of ethane to ethylene and acetic acid is utilized here as a model reaction to demonstrate the benefit of the present invention. Kinetics developed by Thorstienson et al., Journal of Catalysis, vol. 52, pp. 116-132 (1978) are used to describe the rates of reactions involved on this partial oxidation process, those reactions are:
C 2 H 6 +0.5 O 2 →C 2 H 4 +H 2 O
C 2 H 4 +O 2 →CH 3 COOH
C 2 H 6 +3.5 O 2 →2CO 2 +3H 2 O
C 2 H 4 +2O 2 →2CO+2H 2 O
CH 3 COOH+O 2 →2CO+2H 2 O
CO+0.5 O 2 →CO 2
C 2 H 4 +3.0 O 2 →2CO 2 +2H 2 O
[0094] Model equations have been developed for the catalyst tube resulting in a system of non-linear ordinary differential equations which were solved numerically to predict the non-isothermal behavior of the reaction. This is to calculate the reacting mixture compositions, pressure and temperature at each point along the length of the reactor tube.
[0095] The model was then used to simulate operating scenarios where the target in each one was to maximize the production of ethylene and acetic acid without having a oxygen concentration higher than that of the lower explosion limit of the ethane-oxygen mixture (estimated as 8% oxygen in ethane under the elected operating conditions).
[0096] Operating variables and design parameters for the three cases (Cases I, II and III) which were studied using the model are provided in Table II. The predicted performance is also given in the same table.
TABLE II Case I Case II Case III Ethane Flow, SLPH 8280 8280 8280 Oxygen Flow at entrance, SLPH 720 720 720 Oxygen Flow Distributed, SLPH — 400 1000 Feed Temperature, C. 120 120 120 Coolant Temperature, C. 256 254 254 Feed Press, Barg. 26 26 26 Catalyst Tube ID mm 24.3 24.3 24.3 Catalyst Tube OD mm 33.4 33.4 33.4 Catalyst Tube Length, mm 1250 1250 1250 Central Tube OD, mm — 6 6 Ethane conversion, % 4.0 5.6 7.6 Oxygen Conversion, % 92.8 85.0 77.6 Selectivity to (Ethylene + Acetic Acid) 72.8 70.1 68.0 Overall Performance in STY (Tons of 593 803 1058 desired products per ton Catalyst per Year)
[0097] In Case I, the reactor is of the conventional fixed bed type, and the feed composition is constrained by the explosion limit of 8% O 2 in the mixture.
[0098] The second scenario (Case II) employs a reactor of the type proposed by Tonkovich et al. (1996) in Chem. Eng. Science, vol. 51, in which the distribution of more oxygen than that allowed in the main feed is carried out continuously along the catalyst bed by means of a porous central tube. The amount of oxygen flowed through the central tube was limited by the oxygen concentration at intermediate points in the catalyst bed.
[0099] The third scenario (Case III) has a special oxygen flow distribution pattern, as shown in FIG. 10 . The same constraint of 8% oxygen concentration was used for this case. However, the non-uniform/controlled distribution pattern gave rise to a much superior reactor performance, as it allowed for much more oxygen to be fed to the reaction system, thus increasing the ethane conversion and the catalyst tube productivity. The preferred embodiment of the invention (Case III) provides a performance improvement of 78% over the conventional reactor and 32% over the uniform oxidant distribution option (Case II).
[0100] Moreover, the invention provides for better control over the catalyst bed temperature as shown in FIG. 11 , maintaining the catalyst and reaction mixture in a preferred operating temperature range, while this advantage was not achievable neither by conventional reactor nor by the uniform distribution option.
[0101] Another reason for the superior performance demonstrated is the ability of the novel reactor to maintain the oxygen concentration within a favorable range along the length of the reaction zone, as can be seen in FIG. 12 .
Example 2
[0102] The reaction of ethane oxidation was performed using a pilot scale testing unit illustrated in FIG. 13 . The following is a description of the testing rig:
[0103] A. Feed Section
[0104] The feed section consisted mainly of clusters of compressed gas cylinders with manifolds and mass flow controllers. The feed section was constructed to feed into the reactor the following reactants: ethane, air, oxygen, carbon dioxide and nitrogen. Mass flow controllers on each gas feed line were operated from a remote location. A forward pressure regulator on each gas feed line maintained the desired pressure of the reactants.
[0105] B. Reactor Section
[0106] The prototype multi-injection reactor was constructed from 316 stainless steel with a length of 12.5 m. It was bent into a U-shape to keep the structure within a reasonable height. The reactor consisted of an inner (distribution) tube, a thermowell, an outer tube and a shell. The inner tube and the thermowell were situated inside the outer tube, which was filled with a catalyst of the type described in the U.S. Pat. No. 6,030,920, U.S. Pat. No. 6,013,597 and U.S. Pat. No. 5,907,056. The shell surrounded the outer tube. The dimensions of the tubes and the shell are as follows:
Outer diameter, mm Thickness, mm Inner tube 12 1.5 Thermowell 8 1.5 Outer tube 44.5 2.6 Shell 88.9 4.0
[0107] The inner tube had distribution points along its length equipped with custom-built injectors. The size and number of injector holes were designed to provide the following flow pattern:
Location from tube entrance, mm 2000 4000 6000 8000 10500 Percentage of the total 8 11 30 28 23 flow to the inner tube
[0108] Steam was circulated in the shell of the reactor counter currently to accomplish the required heat removal. A differential pressure transmitter (“DPT”) was installed to monitor the total pressure drop along the reactor catalyst bed. A provision for sampling the reaction mixture was made at four different points along the catalyst bed.
[0109] C. Product Handling
[0110] The product gases from the reactor were then transferred to a shell and tube heat exchanger, where product condensation was achieved by a chilled water being circulated on the shell side. The two phase flow exiting the exchanger was sent to a gas liquid separator, from which gases were vented and liquids were collected in a receiving tank. Both condensation and separation of the product took place under the system pressure by means of a back pressure regulator installed on the vent gas line leaving the condensate separator.
[0111] D. Heat Transfer System
[0112] The heat transfer system included a steam drum and an air blower. The steam drum was located at a point above the reactor and was connected to the shell side of the reactor. The air blower was connected to the jacket of the drum to cool the steam. The system was instrumented with a level transmitter to indicate the level of water in the drum, a temperature transmitter, a pressure transmitter and safety relief valve.
[0113] E. Results
[0114] A comparison is given below in Table III for two experimental runs, where in the first run the oxygen feed was introduced according to the distribution scheme given earlier. While in the second run the inner tube was replaced by a dummy tube and only the allowable oxygen due to the explosion limit was introduced with the hydrocarbon at the reactor entrance (e.g., single oxygen inlet with hydrocarbon feed). All other conditions (coolant temperature, reaction peak temperature, hydrocarbon flow, system pressure, etc.) were kept the same.
TABLE III Run #1 Run #2 Total flow, m 3 /h 33.28 33.3 Percentage ethane 44.95 45.05 Oxygen injected 3.3 0.0 Pressure, barg 26.0 26.0 Coolant Temperature, C. 251.0 251.0 Peak Temperature, C. 278.0 278.0 Ethane conversion, % 13.02 8.69 Oxygen Outlet, % 5.51 0.52 Acetic Acid Selectivity, % 59.24 48.12 Ethylene Selectivity, % 16.38 25.38 CO 2 Selectivity, % 23.34 25.74 Acetic Acid Productivity, kg 1171.7 636.9 Acid/kg Catalyst/year
[0115] As shown in Table III, the present invention (Run #1) provides a productivity to acetic acid at least 80% greater than the productivity provided by the comparative embodiment (Run #2). Moreover, both the ethane conversion and acetic acid selectivity is improved using the invention.
[0116] Reference is also made to copending U.S. application Ser. No. ______ (Attorney Reference Number 0080577-0090) by Adris et al. and entitled “Tubular Reactor with Gas Injector For Gas Phase Catalytic Reactions” filed on even date herewith, herein incorporated by reference.
[0117] The above description of the invention is intended to illustrative and not limiting. Various changes or modifications in the embodiments described may occur to those skilled in the art. These can be made without departing from the spirit or scope of the invention.
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An apparatus for performing continuous flow chemical reactions such as oxidation, oxidative dehydrogenation and partial oxidation processes involving a reactor design characterized by controlled/optimized addition of a reactant with the objective of: (i) avoiding the explosion regime of the reactant mixture (e.g., hydrocarbon/oxidant mixture); (ii) maximizing the selectivity of the reaction to the desired product; (iii) limiting the reactor temperature gradient and therefore the threat of reaction runaway; and (iv) controlling the operating temperature of the reaction zone so that desirable temperature range is maintained over the entire zone.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to decorative trim for various construction projects. More particularly, the invention comprises a decorative trim cap for structural elements such as decks, posts and railings which provide protective cover against warping, splintering and cracking, in addition to providing an aesthetically pleasing trim to what are often rather course structures.
[0003] 2. Description of the Prior Art
[0004] In the building of outdoor structures such as porches, decks and gazebos, structures which are often of a rather course construction, it is desirable provide an aesthetically pleasing trim to enhance the appearance of certain structural elements, as well as to protect the end grain of exposed elements such as vertical posts and railings from warping, splintering and cracking. To this end, others have presented a variety of solutions.
[0005] U.S. Pat. No. 5,326,187, issued to St. Marie, et al., on Jul. 5, 1994, presents a cover for covering the upper rail of a railing. The upper cover has a top, bottom and side to encase the exposed surfaces of the rail. The cover has a curved top with a concave inner surface to be positioned adjacent the top of the rail. Longitudinal ribs on the inner surface spaces the cover away from the top surface of the railing. In contrast to the present invention, St. Marie, et al., is adapted to encase expanses of lateral surfaces, while providing no decorative features other than the arch upper surface of the cover.
[0006] U.S. Pat. No. 5,794,390, issued to Oliveri, et al., on Aug. 18, 1998, presents a structural covering that is attachable to a rail of a railing that has a top, a pair of sides, ends, and a bottom, and that is attachable to a floorboard of a deck that has a top, a pair of sides, ends, and a bottom, while covering most of the rail of the railing and any exposed ends thereof and covering most of the floorboard of the deck and any exposed ends thereof so as to prevent splinters, hide knots, splintered wood, discolored wood and cracks in the wood. The patent to Oliveri, et al., is in distinct contrast to the present invention in that it is adapted to cover large expanses of lateral surfaces while providing no decorative features other than the arch of the upper surface.
[0007] U.S. Pat. No. 6,062,519, issued to Baldassarre on Aug. 18, 1998, presents a a rail covering system for covering the railing of an outdoor deck to protect the railing from damage from weathering. The system includes an elongate strip having top and bottom faces, a pair of opposite ends, and a pair of sides extending between the ends of the strip. The bottom face of the strip is designed for resting on a top of a railing. Each of the sides of the strip has an elongate edge flange extending outwardly therefrom. In contrast to the present invention, the patent to Baldassare is adapted for covering an expanse of lateral surface and does not provide decorative scroll work to enhance the appearance.
[0008] U.S. Pat. No. 6,286,884, issued to Speece on Sep. 11, 2001, presents a cap for the top surfaces of a truck bed sidewall providing a horizontally oriented top bed wall portion and an integral downwardly extending inner and outer portion. In contrast to the present invention, Speece is adapted to cover an expanse of lateral surface and offers no appreciable aesthetic appeal.
[0009] None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.
SUMMARY OF THE INVENTION
[0010] The present invention comprises an aesthetically pleasing end cap for structural members such as decks, posts and railings for outdoor structures such as porches, decks and gazebos. While warping, splintering and cracking are common concerns in such exposed applications, and it is desirable to protect the primary areas of concern (cut end edges and end grains) without having to encase the entire member, the cosmetic enhancement of what are often somewhat raw structural elements is often of equal concern. It is especially desirable to be able to protect these elements while providing aesthetic highlights to the overall structure.
[0011] Accordingly, it is a principal object of the invention to provide a trim cap which will protect cut end edges and end grains from the elements.
[0012] It is another object of the invention to provide a trim cap which will provide an aesthetic appeal to the structural element which it is protecting.
[0013] It is a further object of the invention to provide an trim cap which is economical to manufacture, and therefore to purchase for use.
[0014] Still another object of the invention is to provide a trim cap which is easy to install.
[0015] An additional object of the invention is to provide a trim cap which is durable.
[0016] It is again an object of the invention to provide a trim cap which is easy to maintain.
[0017] It is an object of the invention to provide improved elements and arrangements thereof in an apparatus for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes.
[0018] These and other objects of the present invention will become readily apparent upon further review of the following specification and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Various other objects, features, and attendant advantages of the present invention will become more fully appreciated as the same becomes better understood when considered in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the several views, and wherein:
[0020] [0020]FIG. 1 is a perspective view of a deck top corner cap.
[0021] [0021]FIG. 2 is a plan view of the blank for the deck top corner cap of FIG. 1 prior to braking to shape.
[0022] [0022]FIG. 3 is a perspective view of a deck side corner cap.
[0023] [0023]FIG. 4 is a plan view of the blank for the deck side corner cap of FIG. 3 prior to braking to shape.
[0024] [0024]FIG. 5 is a perspective view of a rail corner cap.
[0025] [0025]FIG. 6 is a plan view of the blank for the rail corner cap of FIG. 5 prior to braking to shape.
[0026] [0026]FIG. 7 is a perspective view of a 90° corner stringer plate.
[0027] [0027]FIG. 8 is a perspective view of a 45° corner stringer plate.
[0028] [0028]FIG. 9 is a plan view of the blank for the corner stringer plates of FIGS. 7 and 8.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0029] The present invention presents a system of decorative caps for structures such as, but not limited to porches, decks and gazebos which provide protection for areas which are most susceptible to weathering, splintering and cracking, such as open end grains and end cut edges. These caps may be brake formed of flat rolled metals, such as, but not limited to, galvanized steel, brass or bronze, or aluminum, or molded of a high impact polymer or similar material. For the purposes of disclosure, brake formed elements will be disclosed, revealing flat blank and formed depictions. It would be evident to one skilled in the art that molded elements would be similar in appearance to the formed views of the brake formed elements disclosed.
[0030] [0030]FIGS. 1 and 2 depict a deck top corner cap 10 . This element would typically be used on the top surface of the corner of a deck where a vertical post is not present, providing protection and aesthetic appeal primarily to the deck surface and protection to the edges of the decking planks at the corner.
[0031] Referring first to FIG. 2, deck top corner cap 10 consists of a generally rectangular (typically square) corner top plate 12 having two adjacent edges 14 which are substantially linear, normal to one another and, typically, of equal length. A corner side plate 16 is formed along each of the two adjacent edges 14 , each corner side plate 16 being substantially rectangular, having a length equal to that of the edge 14 of corner top plate 12 with which it is contiguous and a width equal to that of the other corner side plate 16 . A notch is formed in the blank for deck top corner cap 10 in the quadrant formed between the widths of the two corner side plates 16 . The two edges 18 of corner top plate 12 opposite the two edges 14 are of a freeform shape, thereby creating a decorative design to the overall corner top plate 12 . Typically, corner top plate 12 is symmetrical along a diagonal line from the juncture of the two edges 14 to the juncture of the two edges 16 . It would be evident to one skilled in the art, however, that corner top plate 12 could be totally asymmetrical, thereby providing a different aesthetic effect. A plurality of mounting holes 20 in corner top plate 12 and corner side plates 16 allow for attachment of deck top corner 10 over a corner of a deck structure. The blank of FIG. 2 is brake formed along each of the edges 14 to form the deck top corner cap 10 of FIG. 1.
[0032] Turning now to FIG. 4, a blank for a deck side corner cap 30 consists of a pair of substantially rectangular corner plates 32 abutting one another along corner line 34 . Each corner plate 32 additionally abuts a substantially triangular bottom plate 36 along a bottom line 38 , corner line 34 being substantially centered upon and normal to bottom line 38 . A notch of approximately 90° is formed in the blank for deck side corner cap 30 between the two bottom plates 36 at their juncture with corner line 34 , such that an edge 40 or each bottom plate 36 forms an angle of approximate 45° with respect to bottom line 38 . Outer edges 42 of corner plates 32 may be of a totally freeform shape or a combination of linear and freeform to provide an aesthetic appearance, as may outer edge of bottom plate 36 . However, the two corner plates 32 and two bottom plates 36 are typically symmetrical with one another, although, again, they may be totally asymmetrical. A plurality of mounting holes 46 in corner plates 32 and bottom plates 36 allow mounting over the side edges of a deck corner. The blank for the deck side corner cap 30 of FIG. 4 is brake formed along corner line and bottom line 38 to form the finished deck side corner 30 of FIG. 3, with the bottom edges 40 of the two bottom plates 36 abutting in the finished deck side corner cap 30 . Deck side corner cap 30 is typically used to cover the ends of the stringers surrounding a deck at a corner.
[0033] Turning our attention now to FIG. 6, a rail corner cap 50 consists of a substantially square rail top plate 52 , and two substantially square rail side plates 54 , each rail side plate 54 contiguous with rail top plate 52 along one of two substantially straight, adjacent edges 56 . A straight edge 58 of each rail side plate 54 is formed as a continuation of edges 56 , with an open notch formed in the blank in the quadrant between the edges 58 . The two edges of rail top plate 52 opposite edges 56 and the two edges of rail side plates 54 opposite edges 56 and 58 may be of either a totally freeform shape or a combination of freeform and linear, to thereby provide an aesthetically pleasing appearance. Typically the two rail side plates 54 would be symmetrical to one another, and rail top plate 52 would be symmetrical along a diagonal from the intersections of the two edges 56 to the intersection of the two opposite sides. A plurality of mounting holes 60 in rail top plate 52 and rail side plates 54 allow connection of rail corner cap 50 to a deck railing at a corner joint. The blank for the rail corner cap 50 of FIG. 6 is brake formed along each of the edges 56 to form the rail corner 50 of FIG. 5.
[0034] Now referring to FIG. 9, corner plate 70 consists of two substantially rectangular plate ends 72 joined along a joint 74 . The top 76 and bottom 78 edges of corner plate 70 are substantially linear, adapted to follow the lines of the edges of stringers running around the perimeter of a deck, although portions may be of a freeform shape, particularly at their junctures with the ends 80 of plate ends 72 opposite joint 74 . The ends 80 may be of either a totally freeform shape or a combination of freeform and linear, in order to provide a pleasing aesthetic appearance. A plurality of mounting holes 82 in corner plate 70 facilitate mounting of corner plate 70 along a stringer around the perimeter of a deck. The blank for the corner plate 70 of FIG. 9 is brake formed along joint 74 to form the corner plates 70 of FIGS. 7 (substantially a 90° angle), and 8 (substantially a 45° angle). The angles depicted in FIGS. 7 and 8 could, of course, be manually adjusted during installation, especially in sheet metal embodiments.
[0035] In each embodiment herein presented, the shape is strictly illustrative, as each embodiment may be produced in a myriad of different aesthetic variations. It would be evident to one skilled in the art that, in addition to the aesthetically pleasing lines of each embodiment, surfaces could be embossed with various textures or graphic designs to further enhance their appearance. Likewise, the suggested use of each embodiment is strictly illustrative, as installational applications for any one embodiment are limited only by the imagination of the user.
[0036] It is to be understood that the present invention is not limited to the embodiments described above, but encompasses any and all embodiments within the scope of the following claims.
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A trim cap providing aesthetically pleasing protection and reinforcement to structural members such as decking and railing corners of structures such as porches, decks and gazebos is discloses. Deck top corner, deck side corner, rail corner and butt joint caps have aesthetically pleasing non-linear lines and/or embossed graphic or textural designs which set them apart from the purely structural applications of prior art brackets and caps.
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CROSS-REFERENCE TO RELATED APPLICATION
This application claims the priority benefit of Taiwan application serial no. 91102579, filed Feb. 15, 2002.
BACKGROUND OF THE INVENTION
1. Field of Invention
The present invention relates to a semiconductor transport device. More particularly, the present invention relates to a vacuum suction membrane for holding a silicon wafer.
2. Description of Related Art
Wafer transport systems use a variety of mechanisms for transport, the most common and widely used method of which is creating a vacuum to suck up a silicon wafer. The vacuum suction method is used, for example, in a chemical-mechanical polishing device to hold a silicon wafer.
FIG. 1 is simplified and localized cross-sectional view of a conventional chemical-mechanical polishing device. As shown in FIG. 1 , the chemical-mechanical polishing device includes a polishing head 100 and a polishing table 110 . A polishing pad 120 covers the polishing table 110 . The polishing head 100 further includes a gripping pan 102 having an elastic membrane 106 therein. When the polishing head 100 presses upon a silicon wafer 108 , the downward pressure produced by the polishing head 100 on the wafer 108 is evenly spread out so that the wafer 108 can be polished smoothly.
However, at the end of a chemical-mechanical polishing operation, an external robotic arm is often used to unload the wafer 108 from the polishing table 110 and then transfer the wafer 108 elsewhere. To smooth the process and reduce operating cost, the polishing head 100 often incorporates a vacuum system. In other words, the gripping pan 102 structure is frequently modified to include a set of internal gaseous pipelines. In addition, a multiple-hole panel is inserted between the gripping pan 102 and the membrane 106 such that the membrane 106 also encloses the bottom section of the multiple-hole panel. After a chemical-mechanical polishing operation, a vacuum system may be triggered to create a vacuum state inside the polishing head 100 through the set of internal gaseous pipelines. Hence, the membrane 106 originally pressed against the wafer 108 now attaches to the wafer 108 through suction. Thereafter, the polishing head 100 may move to carry the wafer 108 away. On releasing the vacuum inside the polishing head 100 , suction between the membrane 106 and the wafer 108 disappears and the wafer 108 drops off from the polishing head 100 .
FIG. 2 is a schematic top view of a conventional multiple-hole panel inside a vacuum-suction polishing head. As shown in FIG. 2 , the multiple-hole panel 200 has a shape that corresponds to a silicon wafer. Hence, the multiple-hole panel 200 is circular and contains a number of holes 202 . At the end of a polishing operation, the polishing head is turned into a vacuum state. Through differential pressure acting via the holes 202 , the elastic membrane 106 contracts into the hole 202 resulting in a suction pressure on the wafer.
However, the conventional technique has some drawbacks in real applications. The polishing head must return to normal pressure after a polishing operation so that the wafer attached to the membrane can drop off. Due to considerable suction between the membrane and the wafer, the wafer may not unload normally. In other words, the wafer is still attached to the membrane after the polishing head has returned to a normal pressure. Eventually, the wafer may be damaged due to subsequent mishandling.
In addition, because there is no membrane between the multiple-hole panel for sucking up the wafer and the wafer, the process of creating a suction vacuum also carries some micro-particles from the surrounding atmosphere towards the wafer leading to wafer contamination.
SUMMARY OF THE INVENTION
Accordingly, one object of the present invention is to provide a membrane for vacuum suction of a silicon wafer such that excessive suction pressure between the membrane and the wafer that may lead to unloading failure is prevented.
A second object of this invention is to provide a membrane for vacuum suction of a silicon wafer such that time and labor for processing unloading failure is reduced.
A third object of this invention is to provide a membrane for vacuum suction of a silicon wafer such that contamination of the wafer is prevented.
To achieve these and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, the invention provides a device having a membrane therein typically incorporated into a polishing head for sucking up a silicon wafer. The device includes a flat main body and a plurality of minute protrusions such as micro-particles on the surface of the flat main body. The minute protrusions are positioned over corresponding holes of a polishing head suction panel.
The minute protrusions on the vacuum suction membrane according to this invention are able to reduce suction pressure between the wafer and the membrane after the removal of suction. Hence, the design is able to minimize wafer damage due to unloading failure.
The membrane for vacuum suction of a silicon wafer according to this invention is quite effective in unloading a wafer. Thus, time and labor required to process failure in wafer unloading is minimized and yield of the wafer is increased.
Furthermore, the provision of a membrane between the wafer suction panel and the wafer cuts off all deposition of contaminant particles from surrounding air in the process of creating a vacuum.
It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the invention as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. In the drawings,
FIG. 1 is simplified and localized cross-sectional view of a conventional chemical-mechanical polishing device;
FIG. 2 is a schematic top view of a conventional multiple-hole panel inside a vacuum suction polishing head;
FIG. 3A is a schematic cross-sectional view of a multiple-hole panel and a membrane that encloses the bottom section of the multiple-hole panel according to one preferred embodiment of this invention;
FIG. 3B is a schematic cross-sectional view showing the configuration of the system in FIG. 3A after creating a suction pressure; and
FIG. 4 is a local magnification of a portion IV shown in FIG. 3B .
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Reference will now be made in detail to the present preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts.
This invention provides a membrane for vacuum suction of silicon wafers that can be incorporated with a chemical-mechanical polishing device. The membrane serves as a film for enclosing a multiple-hole panel inside a polishing head. However, the membrane can also be applied to various other vacuum suction devices for transferring or holding wafers.
The chemical-mechanical polishing device used as an example in the description includes a polishing head and a polishing table. The polishing head is connected to a vacuum system. The polishing head further includes a gripping pan for stationing a wafer. Details inside the gripping panel are shown in FIGS. 3A , 3 B and 4 .
FIG. 3A is a schematic cross-sectional view of a multiple-hole panel and a membrane that encloses the bottom section of the multiple-hole panel according to one preferred embodiment of this invention. As shown in FIG. 3A , inside the gripping panel (not shown in the figure) of the polishing head is a multiple-hole panel 300 having a plurality of holes 302 therein. A membrane 304 fabricated according to this invention wraps around the bottom section of the multiple-hole panel 300 . The membrane 304 includes a flat main body 305 and a plurality of minute spiny protrusions 306 on the surface of the flat main body 305 . Both the flat main body 305 and the spiny protrusions 306 are made from an identical material. The spiny protrusions 306 may have a spiny shape, for example. The protrusions 306 are positioned on the membrane 304 over corresponding holes 302 of the multiple-hole panel 300 , for example. For a membrane having a diameter of about 300 mm, each protrusion 306 has a diameter of about 2 mm and a height of about 2 mm. However, the protrusions 306 may have other shapes, dimensions or density on the membrane in order to produce a device having an optimal wafer suction/unloading capability. For example, the quantity of protrusions 306 on the membrane 304 may vary according to the size of holes 302 in the multiple-hole panel 300 . In other words, total quantity of protrusions in an area over a larger hole may be greater than total quantity of protrusions in an area over a smaller bole.
When the polishing head is conducting a polishing operation, the multiple-hole panel 300 presses downward against the wafer. At the end of the polishing operation, the vacuum system is triggered to turn the interior of the polishing head into a vacuum state so that the polishing head can be used as a tool for moving the wafer elsewhere. How the vacuum system of this invention is able to suck up a wafer is explained in greater detail with reference to FIG. 3B .
FIG. 3B is a schematic cross-sectional view showing the configuration of the system in FIG. 3A after creating a suction pressure. As shown in FIG. 3B , air within the polishing head is evacuated in step 308 to create a partial vacuum so that the multiple-hole panel 300 has a pressure differential between the interior and the exterior. Consequently, the portion of membrane 304 positioned directly over the holes 302 cave upward towards the upper section of the multiple-hole panel 300 . Originally, the membrane 304 is pressed tightly against the wafer, but now the membrane 304 attaches to the wafer through suction. Because the membrane 304 has a plurality of minute protrusions 306 on the surface, suction pressure between the membrane 304 and the wafer is slightly lowered when the wafer is attached. Details of how the membrane 304 functions over the hole 302 are further explained using FIG. 4 .
FIG. 4 is a local magnification of a portion IV shown in FIG. 3B . When a vacuum state is created inside the polishing head, the membrane region over the holes 304 caves upward towards the upper section of the multiple-hole panel 300 . Thus, the membrane 304 around the holes produces an upward suction.
A comparison between the membrane of this invention and a conventional design can be made here. In a conventional design, a suction-like counteraction is often created trying to remove the downward pressure on the wafer during the polishing operation. Thus, the counteraction provides a suction force between the membrane and the wafer even before a vacuum suction is created. Hence, when the wafer is carried under vacuum suction, the suction between the wafer and the membrane at the bottom section of the multiple-hole panel exceeds the desired suction considerably. Such an excessive suction often results in a failure to unload the wafer from the polishing head even when the vacuum state is canceled. The failure of disengagement between the polishing head and the wafer may lead to defective polishing when the wafer undergoes a float polishing operation inside a float polisher, for example.
On the contrary, the membrane fabricated according to this invention has protrusions around the holes of the multiple-hole panel. Since the protrusions cancel most of the suction due to counteraction after removing the pressure on the wafer, there is no excess counteraction before the creation of a vacuum suction between the wafer and the membrane. Once the vacuum state in the polishing head is relieved, suction between the wafer and the membrane immediately disappears and the wafer unloads from the membrane smoothly. Consequently, the probability of wafer unloading failure is greatly reduced.
In addition, if this invention is applied to other vacuum suction transport or wafer holding systems, the presence of a membrane between the multiple-hold panel and the wafer prevents any deposition of contaminants on the wafer when the vacuum is created.
It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents.
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A membrane for vacuum suction of a silicon water typically used inside a polishing head. The membrane has a flat main body and a plurality of protrusions each having a spiny shape over the surface of the flat main body. The protrusions are formed in positions that correspond to the holes of a supporting multiple-hole panel. The protrusions on the flat main body lower the suction pressure between the wafer and the membrane somewhat so that wafer unloading failure is minimized.
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CROSS-REFERENCE TO RELATED APPLICATION
This application is a continuation-in-part of application Ser. No. 103,012, filed Dec. 13, 1979, now abandoned.
BACKGROUND OF THE INVENTION
This invention relates to novel semi-synthetic antifungal compounds which are prepared by the acylation of the cyclic peptide nucleus produced by the enzymatic deacylation of antibiotic A30912 factor A.
Antibiotic A-30912 factor A is an antifungal cyclic peptide having the formula: ##STR3## wherein R is the linoleoyl group ##STR4## Throughout this application, the cyclic peptide formulas, such as formula I, assume that the amino acids represented are in the L-configuration. The factor is isolated from the A30912 complex which contains other factors arbitrarily designated factors B, C, D, E, F and G. The A-30912 complex and the individual factors A through G are described by M. Hoehn and K. Michel in U.S. Pat. No. 4,024,245. Factor A is identical to antibiotic A-22802 which is described by C. Higgins and K. Michel in U.S. Pat. No. 4,024,246. Factor A has also been found to be identical to antibiotic echinocandin B [see F. Benz et al., Helv. Chim. Acta, 57, 2459 (1974) and Swiss Pat. No. 568,386] and to antibiotic SL 7810/F [see C. Keller-Juslen et al. Tetrahedron Letters, 4147 (1976) and Belgium Pat. No. 834,289].
Antibiotic A-30912 factor A is prepared by fermentation using one of several different organisms, namely: (a) Aspergillus rugulosus NRRL 8113 (see U.S. Pat. No. 4,024,245); (b) Aspergillus nidulans NRRL 8112 (see U.S. Pat. No. 4,024,246); (c) Aspergillus nidulans var. echinulatus A-32204 as described in Swiss Patent No. 568,386; (d) Aspergillus rugulosus NRRL 8039 (see Belgian Pat. No. 834,289); or (e) Aspergillus nidulans var. roseus NRRL 11440 [see co-pending application of L. Boeck and R. Kastner, METHOD OF PRODUCING THE A-30912 ANTIBIOTICS, Ser. No. 126,078, filed Mar. 3, 1980, which is a continuation-in-part of application Ser. No. 46,744, filed June 8, 1979 (now abandoned), the entire disclosure of which is incorporated herein by reference].
A subculture of A. nidulans var. roseus has been deposited and made a part of the permanent culture collection of the Northern Regional Research Laboratory, U.S. Department of Agriculture, Agricultural Research Service, Peoria, Ill. 61604, from which it is available to the public under the number NRRL 11440.
When a strain of A. nidulans var. roseus NRRL 11440 is used to produce A-30912 factor A, a complex of factors is obtained which for convenience is called the A-42355 antibiotic complex. A-30912 factor A is the major factor of the A-42355 antibiotic complex, while factors B, D and H are minor factors. Examples 10, 11, and 12 herein, illustrate the preparation of the A-42355 complex and the isolation and purification of A-30912 factor A therefrom. A-30912 factor H is further described in a co-pending application of Karl H. Michel entitled ANTIBIOTIC A-30912 FACTOR H, Ser. No. 117,739 filed Feb. 1, 1980, which is a continuation-in-part of application Ser. No. 46,875, filed June 8, 1979 (now abandoned).
In the A-30912 factor A molecule (Formula I), the linoleoyl side chain (R) is attached at the cyclic peptide nucleus at the α-amino group of the dihydroxyornithine residue. Surprisingly, it has been found that the linoleoyl side chain can be cleaved from the nucleus by an enzyme without affecting the chemical integrity of the nucleus. The enzyme employed to effect the deacylation reaction is produced by a microorganism of the family Actinoplanaceae, preferably the microorganism Actinoplanes utahensis NRRL 12052 or a variant thereof. To accomplish deacylation, antibiotic A30912 factor A is added to a culture of the microorganism, and the culture is allowed to incubate with the substrate until the deacylation is substantially complete. The cyclic nucleus thereby obtained is separated from the fermentation broth by methods known in the art. Unlike antibiotic A-30912 factor A, the cyclic nucleus (lacking the linoleoyl side chain) is substantially devoid of antifungal activity.
The cyclic nucleus afforded by the afore-described enzymatic deacylation of antibiotic A-30912A factor A is depicted in Formula II. ##STR5##
Removal of the side chain group affords a free primary α-amino group in the dihydroxyornithine residue of the cyclic peptide. For convenience, the compound having the structure given in Formula II will be referred to herein as "A-30912A nucleus." As will be apparent to those skilled in the art, A-30912A nucleus can be obtained either in the form of the free amine or of the acid addition salt. Although any suitable acid addition salt may be employed, those which are non-toxic and pharmaceutically acceptable are preferred.
The method of preparing a-30912A nucleus from antibiotic A-30912 factor A by means of fermentation using Actinoplanes utahensis NRRL 12052 is described in the co-pending application of Bernard J. Abbott and David S. Fukuda entitled "A-30912A NUCLEUS", Ser. No. 103,017, filed Dec. 13, 1979, continued in an application (Ser. No. 103,012) filed herewith this even date, the full disclosure of which is incorporated herein by reference. Example 7 herein illustrates the preparation of A-30912A nucleus by fermentation using antibiotic A-30912 factor A as the substrate and Actinoplanes utahensis NRRL 12052 as the microorganism.
The enzyme produced by Actinoplanes utahensis NRRL 12052 may be the same enzyme which has been used to deacylate penicillins (see Walter J. Kleinschmidt, Walter E. Wright, Frederick W. Kavanagh, and William M. Stark, U.S. Pat. No. 3,150,059, issued Sept. 22, 1964).
Cultures of representative species of Actinoplanaceae are available to the public from the Northern Regional Research Laboratory under the following accession numbers:
______________________________________Actinoplanes utahensis NRRL 12052Actinoplanes missouriensis NRRL 12053Actinoplanes sp. NRRL 8122Actinoplanes sp. NRRL 12065Streptosporangium roseumvar. hollandensis NRRL 12064______________________________________
The effectiveness of any given strain of microorganism within the family Actinoplanaceae for carrying out the deacylation of this invention is determined by the following procedure. A suitable growth medium is inoculated with the microorganism. The culture is incubated at about 28° C. for two or three days on a rotary shaker. One of the substrate antibiotics is then added to the culture. The pH of the fermentation medium is maintained at about pH 6.5. The culture is monitored for activity using a Candida albicans assay. Loss of antibiotic activity is an indication that the microorganism produces the requisite enzyme for deacylation. This must be verified, however, using one of the following methods: 1) analysis by HPLC for presence of the intact nucleus; or 2) re-acylation with an appropriate side chain (e.g. linoleoyl, stearoyl, or palmitoyl) to restore activity.
It is known that other antibiotic substances possess the same nucleus as that of Antibiotic A-30912 factor A. These antibiotics differ from antibiotic A-30912 factor A in that different acyl groups are present in place of the linoleoyl group (R) in Formula I. Such antibiotics are: (a) tetrahydro-A-30912 factor A (tetrahydro-SL 7810/F; tetrahydro-echinocandin B) described in Belgium Patent 834,289 and by F. Benz et al., Helv. Chim. Acta, 57 2459 (1974), which compound is depicted in Formula I when R is stearoyl; and (b) aculeacin A, which is a component of the aculeacin complex (prepared by fermentation using Aspergillus aculeatus NRRL 8075) and is described by K. Mizuno et al., in U.S. Pat. No. 3,978,210. As is discussed in Belgium Patent 859,067, in aculeacin A the palmitoyl side chain is present in place of linoleoyl. Tetrahydro-A-30912 factor A can be prepared from antibiotic A-30912 factor A by catalytic hydrogenation using PtO 2 in ethanol under positive pressure. Both tetrahydro-A-30912 factor A and aculeacin A can be employed as substrates for the enzymatic deacylation using the procedures herein described.
SUMMARY OF THE INVENTION
The invention sought to be patented comprehends novel compounds derived by acylating the A-30912A nucleus (Formula II). The compounds of the present invention have the chemical structure depicted in Formula III: ##STR6## wherein R 1 is a group of the formula: ##STR7## wherein A is divalent oxygen, sulfur, sulfinyl, or sulfonyl; A 1 is divalent oxygen, sulfur, sulfinyl, sulfonyl or --NH--; X is hydrogen, chloro, bromo, iodo, nitro, C 1 -C 3 alkyl, hydroxy, C 1 -C 3 alkoxy, mercapto, C 1 -C 3 alkylthio, carbamyl or C 1 -C 3 alkylcarbamyl; X 1 is chloro, bromo or iodo; R 2 is hydrogen, C 1 -C 18 alkyl or C 2 -C 18 alkenyl; W is C 1 -C 10 alkylene or C 2 -C 10 alkenylene; m, n and p are 0 or 1, but if m=0, n must=0; provided: that the sum of the carbon atoms in the R 2 and W groups must be greater than 4 but cannot exceed 21; that when X is mercapto, A and A 1 cannot be sulfinyl or sulfonyl; and that when A and A 1 are sulfinyl or sulfonyl, they must be in equal oxidation states.
A preferred subgroup of formula III compounds are those of group (a) wherein m and n=0, p=1, and R 2 is C 5 -C 18 alkyl or C 5 -C 18 alkenyl.
It will be recognized by those skilled in the art that in the substituted ring of the R 1 group, the ##STR8## function and the --AR 2 function may be oriented on the benzene ring in the ortho, meta, or para position relative to each other. The para orientation for these groups is preferred. The substituent represented by X may be substituted at any available position of the benzene ring not occupied by these two groups.
As employed herein, the term "alkyl " or "alkenyl" comprehend both straight and branched hydrocarbon chains. By "alkenyl" is meant an unsaturated hydrocarbon group containing one, two, or three double bonds which may be either in the cis or trans configuration.
Illustrative C 5 -C 18 alkyl radicals which are preferred for R 2 for the purposes of this invention are:
(a) --(CH 2 ) n' CH 3 wherein n' is in integer from 4 to 17; and
(b) ##STR9## wherein r and s are, independently, an integer from 0 to 15, provided that r+s can be no greater than 15 or no less than 2.
Illustrative C 5 -C 18 alkenyl radicals, which are preferred for R 2 for the purposes of this invention, are:
(a) --(CH 2 ) t --CH═CH--(CH 2 ) n" --CH 3 wherein t is an integer from 1 to 15, and n" is an integer from 0 to 15 provided that t+n" can be no greater than 15 or no less than 2; and
(b) --(CH 2 ) v --CH═CH--(CH 2 ) y --CH═CH--(CH 2 ) z --CH 3 wherein v and z are, independently, an integer from 0 to 12 and y is an integer from 0 to 13 provided that v+y+z must be no greater than 13.
Illustrative C 1 -C 10 -alkylene radicals, which are preferred W groups for the purposes of this invention, are:
(a) --(CH 2 ) n''' -- wherein n''' is an integer from 1 to 10;
(b) methylene and ethylene; and
(c) ##STR10## wherein r' and s' are, independently, integers from 0 to 8, provided that r'+s' can be no greater than 8 or no less than 1.
Illustrative C 2 -C 10 -alkenylene radicals, which are preferred W groups for the purposes of this invention, are:
(a) --(CH 2 ) t' --CH═CH--(CH 2 ) v' - wherein t' and v' are, independently, integers from 0 to 8, provided that t'+v' must be no greater than 8;
(b) --(CH 2 ) x' --CH═CH--(CH 2 ) y' --CH═CH--(CH 2 ) z' -- wherein x' and z' are, independently, integers from 0 to 5, and y' is an integer from 1 to 5, provided that x'+y'+z' must be no greater than 10.
DETAILED DESCRIPTION OF THE INVENTION
The compounds of Formula III inhibit the growth of pathogenic fungi as evidenced by standard biological test procedures. The compounds are useful, therefore, for controlling the growth of fungi on environmental surfaces (as an antiseptic) or in treating infections caused by fungi. The antifungal activity of the compounds has been demonstrated against Candida albicans in vitro in agar plate disc diffusion tests or agar tube dilution tests, or in vivo in tests in mice infected with C. albicans. Thus, the compounds are particularly useful in treating infections caused by strains of C. albicans (candidosis). The compounds of Formula III have also shown activity in vitro in agar-plate disc diffusion tests against Trichophyton mentagrophytes, a dermatophytic organism. Activity has also been found in in vitro agar-plate disc-diffusion tests against Saccharomyces pastorianus, and Neurospora crassa. Certain compounds (as shown in Example 6, Table 9) give significant blood levels upon oral administration in mice.
When given to a dog by intravenous administration, 100 mg/kg per day for five days, the compound of Formula III wherein R 1 is p-(n-octyloxy)benzoyl showed no outward signs of toxicity, although increased SGPT levels were observed.
The compounds of Formula III are prepared by acylating A-30912A nucleus at the α-amino group of dihydroxynithine with the appropriate side chain using methods conventional in the art for forming an amide bond. The acylation is accomplished, in general, by reacting the nucleus with an activated derivative of the substituted compound of Formula IV (a), (b) or (c) corresponding to the desired acyl side chain group (R 1 ). ##STR11## (A, A 1 , W, m, n, p and R 2 have the meanings herein described supra.)
By the term "activated derivative" is meant a derivative which renders the carboxyl function of the acylating agent reactive to coupling with the primary amino group to form the amide bond which links the side chain to the nucleus. Suitable activated derivatives, their methods of preparation, and their methods of use as acylating agents for a primary amine will be recognized by those skilled in the art. Preferred activated derivatives are: (a) an acid halide (e.g. acid chloride), (b) an acid anhydride (e.g. an alkoxyformic acid anhydride or aryloxyformic acid anhydride) or (c) an activated ester (e.g. a 2,4,5-trichlorophenyl ester, an N-hydroxybenztriazole ester, or an N-hydroxysuccinimide ester). Other methods for activating the carboxyl function include reaction of the carboxylic acid with a carbonyldiimide (e.g. N,N'-dicyclohexylcarbodiimide or N,N'-diisopropylcarbodiimide) to give a reactive intermediate which, because of instability, is not isolated, the reaction with the primary amine being carried out in situ.
A preferred method for preparing the compounds of Formula III is by the active ester method. The use of the 2,4,5-trichlorophenyl ester of the desired side chain acid (Formula IV) as the acylating agent is most preferred. In this method, an excess amount of the active ester is reacted with the nucleus at room temperature in a non-reactive organic solvent such as dimethylformamide (DMF). The reaction time is not critical, although a time of about 24 to about 120 hours is preferred. At the conclusion of the reaction, the solvent is removed, and the residue is purified by chromatography, such as over silica gel using ethyl acetate-methanol (3:2, v/v) as the eluent, or by reversed phase HPLC using silica gel C 18 reversed phase resin as the stationary phase and a mixture of H 2 O/CH 3 OH/CH 3 CN as the solvent system.
The 2,4,5-trichlorophenyl esters are conveniently made by treating the side chain acid (Formula IV) with 2,4,5-trichlorophenol in the presence of a coupling agent, such as N,N'-dicyclohexylcarbodiimide. Other methods of preparation of the active esters will be apparent to those skilled in the art.
The substituted acids of Formula IV, and the activated derivatives thereof, are either known compounds or they can be made from known compounds by methods known in the art. The benzoic, phenylalkylcarboxylic, phenylalkenylcarboxylic, phenoxyalkylcarboxylic, phenoxyalkenylcarboxylic, phenylthioalkylcarboxylic, phenylthioalkenylcarboxylic, phenylsulfinylalkylcarboxylic, phenylsulfinylalkenylcarboxylic, phenylsulfonylalkylcarboxylic, phenylsulfonylalkenylcarboxylic, pyridinylcarboxylic, pyridinylalkylcarboxylic, and pyridinylalkenylcarboxylic acids of Formula IV are prepared by similar procedures. To illustrate these procedures, a discussion of the preparation of the benzoic acid subgroup is provided.
The alkoxybenzoic acids or alkenyloxybenzoic acids can be prepared conveniently from an appropriate hydroxybenzoic acid by reacting an appropriate alkyl or alkenyl halide with the disodium salt of the appropriate hydroxybenzoic acid. The (alkylthio)benzoic acids or the (alkenylthio)benzoic acids can be prepared conveniently by treating the appropriate substituted S-(4-carbomethoxyphenyl)dimethylthiocarbamate of the general formula CH 3 CO 2 C 6 H 3 XS(CO)N(CH 3 ) 2 with aqueous sodium hydroxide at 65°-85° C., then adding the appropriate alkyl or alkenyl bromide, and continuing heating for 2-4 hours. The substituted S-(4-carbomethoxyphenyl)dimethylthiocarbamates can be made from the appropriate hydroxybenzoic acids by the method of M. Newman and H. Kanes, J. Org. Chem., 31, 3980 (1966).
When it is desired to prepare a compound of Formula III wherein A is sulfinyl or sulfonyl, the appropriate sulfoxide or sulfone derivative of the (alkenylthio)- or (alkylthio)benzoic acid (Formula IV) can be employed for acylation of the nucleus. The appropriate sulfoxides or sulfones can be made by oxidation of the corresponding thioether compound using conventional agents, such as m-chloroperbenzoic acid, t-butylhypochlorite, sodium metaperiodate, or hydrogen peroxide. If a double bond is present in the thioether, very mild conditions should be employed to avoid epoxidation. If equimolar amounts of reactants are taken, the product is a sulfoxide (A is sulfinyl), which is readily oxidized to the sulfone (A is sulfonyl) by an additional mole of the oxidizing agent. The hydroxybenzoic acids and substituted derivatives thereof used as starting material in the processes described herein are either known compounds or can be prepared by conventional methods which are known in the art.
When employed systemically, the dosage of the compounds of Formula III will vary according to the particular compound being employed, the severity and nature of the infection, and the physical condition of the subject being treated. Therapy should be initiated at low dosages, the dosage being increased until the desired antifungal effect is obtained. The compounds can be administered intravenously or intramuscularly by injection in the form of a sterile aqueous solution or suspension to which may be added, if desired, various conventional pharmaceutically acceptable preserving, buffering, solubilizing, or suspending agents. Other additives, such as saline or glucose may be added to make the solutions isotonic. The proportions and nature of such additives will be apparent to those skilled in the art.
Certain compounds of Formula III give significant blood levels after oral administration (see Example 6, Table 9) and can be administered systemically by the oral route. For oral use, such compounds can be administered in combination with pharmaceutically acceptable carriers or excipients in the form of capsules, tablets or powders. The nature and proportion of such carriers or excipients will be recognized by those skilled in the art.
When employed to treat vaginal candida infections, the compounds of Formula III can be administered in combination with pharmaceutically acceptable conventional excipients suitable for intravaginal use. Formulations adapted for intravaginal administration will be known to those skilled in the art.
The methods of making and using the compounds of the present invention are illustrated in the following examples:
EXAMPLE 1
Tables 1 through 7 below, give the preparation, respectively, of various alkoxybenzoic acids, (alkylthio)benzoic acids, alkoxyphenylacetic acids, alkoxyphenylpropanoic acids, alkoxycinnamic acids, alkoxyphenoxyacetic acids, and alkoxynicotinic acids.
The preparation of these formula IV acids is typified by the preparation of the alkoxybenzoic acids of Table 1 and the (alkylthio)benzoic acids of Table 2. The general procedure for the preparation of these acids is described in the following paragraphs.
The alkoxybenzoic acids set forth in Table 1 are prepared according to the following general procedure:
p-Hydroxybenzoic acid is dissolved in 10% aqueous sodium hydroxide (two equivalents), and the resulting solution is added to dimethyl sulfoxide (DMSO) (200 ml). The alkyl bromide (one equivalent) is added to the solution at 65°-80° C. The solution is then stirred for two hours after which it is poured into a large volume (600 ml.) of water and acidified with hydrochloric acid. The alkoxybenzoic acid, which precipitates from the solution, is collected by filtration and crystallized from methanol.
The (alkylthio)benzoic acids set forth in Table 2 are prepared according to the following general procedure: To a suspension of sodium hydride (one equivalent, 50% dispersion in mineral oil) in DMF (100 ml per 50 mmole), cooled to 0° C., is added slowly methyl p-hydroxybenzoate (one equivalent). The reaction mixture is stirred under a nitrogen atmosphere until the evolution of hydrogen ceases. To the solution of sodium 4-carbomethoxyphenolate so produced, is added N,N-dimethylthiocarbamoyl chloride [(CH 3 ) 2 N(CS)Cl] (one equivalent) in one portion. The resulting suspension is heated to 70° C. for 1-3 hours and then is poured into an aqueous solution (1%) of potassium hydroxide (large excess). The suspension is extracted twice with toluene-hexane (4:1 v/v). After drying over MgSO 4 , the organic extracts are filtered and evaporated to an oil. The oil is purified by chromatography over silica gel using 2% methanol in methylene chloride to give O-(4-carbomethoxyphenyl)dimethylthiocarbamate [p-CH 3 CO 2 C 6 H 4 O (CS)N(CH 3 ) 2 ]. (mp 97°-102° C.). This product is heated under a nitrogen atmosphere at 220° C. for 30-60 min. to give S-(4-carbomethoxyphenyl)dimethylthiocarbamate [p-CH 3 CO 2 C 6 H 4 S(CO)N(CH 3 ) 2 ] which is crystallized from methanol. To S-(4-carbomethoxyphenyl)dimethylthiocarbamate, dissolved in DMSO, is added 2 equiv. of sodium hydroxide (10% aqueous). The mixture is heated at 65°-85° C., and the alkyl bromide (1 equiv.) is added. Heating is continued for 2-4 hours after which the mixture is poured into a large volume of water. Upon acidification, a precipitate forms, which is collected by filtration. The (alkylthio)benzoic acid is crystallized from methanol.
TABLE 1__________________________________________________________________________Preparation of Alkoxybenzoic AcidsAlkyl Bromide Weight of Alkoxybenzoic AcidFormula Weight p-Hydroxybenzoic Acid Formula Weight__________________________________________________________________________CH.sub.3 (CH.sub.2).sub.7 Br 9.65 g. 6.9 g. ##STR12## 6.18 g.CH.sub.3 (CH.sub.2).sub.9 Br 11.05 g. 6.9 g. ##STR13## 6.79 g.CH.sub.3 (CH.sub.2).sub.13 Br 13.85 g. 6.9 g. ##STR14## 6.18 g.CH.sub.3 (CH.sub.2).sub.7 Br 9.1 g. 6.4 g. ##STR15## 6.69 g.CH.sub.3 (CH.sub.2).sub.9 Br 10.8 g. 6.4 g. ##STR16## 10.2 g.CH.sub.3 (CH.sub.2).sub.11 Br 11.7 g. 6.4 g. ##STR17## 10.9 g.CH.sub.3 (CH.sub.2).sub.13 Br 13.0 g. 6.4 g. ##STR18## 7.3 g.__________________________________________________________________________
TABLE 2__________________________________________________________________________Preparation of Alkylthiobenzoic Acids Weight ofAlkyl Bromide S-(4-carbomethoxyphenyl)- Alkylthiobenzoic AcidFormula Weight dimethylthiocarbamate Formula Weight__________________________________________________________________________CH.sub.3 (CH.sub.2).sub.7 Br 386 mg. 478 mg. ##STR19## 405 mg.CH.sub.3 (CH.sub.2).sub.9 Br 1.77 g. 1.91 g. ##STR20## 1.34 g.CH.sub.3 (CH.sub.2).sub.11 Br 1.99 g. 1.99 g. ##STR21## 1.8 g.CH.sub.3 (CH.sub.2).sub.13 Br 2.22 g. 1.91 g. ##STR22## 2.3 g.__________________________________________________________________________
TABLE 3__________________________________________________________________________Preparation of Alkoxyphenylacetic AcidsAlkyl Bromide Weight of Alkoxyphenylacetic AcidFormula Weight Hydroxyphenylacetic Acid Formula Weight__________________________________________________________________________CH.sub.3 (CH.sub.2).sub.7 Br 3.86 g. 3.04 g. ##STR23## 2.56 g.CH.sub.3 (CH.sub.2).sub.11 Br 4.98 g. 3.04 g. ##STR24## 3.70 g.CH.sub.3 (CH.sub.2).sub.7 Br 3.86 g. 3.04 g. ##STR25## 3.72 g.CH.sub.3 (CH.sub.2).sub.11 Br 4.98 g. 3.04 g. ##STR26## 2.72 g.CH.sub.3 (CH.sub.2).sub.7 Br 3.56 g. 3.04 g. ##STR27## 1.87 g.__________________________________________________________________________
TABLE 4__________________________________________________________________________Preparation of Alkoxyphenylpropanoic Acids Weight ofAlkyl Bromide p-Hydroxyphenylpropanoic Alkoxyphenylpropanoic AcidFormula Weight Acid Formula Weight__________________________________________________________________________CH.sub.3 (CH.sub.2).sub.3 Br 2.74 g. 3.32 g. ##STR28## 2.97 g.CH.sub.3 (CH.sub.2).sub.4 Br 3.02 g. 3.32 g. ##STR29## 2.80 g.CH.sub.3 (CH.sub.2).sub.5 Br 3.30 g. 3.32 g. ##STR30## 3.53 g.CH.sub.3 (CH.sub.2).sub.6 Br 3.58 g. 3.32 g. ##STR31## 2.90 g.CH.sub.3 (CH.sub.2).sub.7 Br 5.79 g. 4.98 g. ##STR32## 4.65 g.CH.sub.3 (CH.sub.2).sub.11 Br 7.47 g. 4.98 g. ##STR33## 4.01 g.__________________________________________________________________________
TABLE 5__________________________________________________________________________Preparation of Alkoxycinnamic AcidsAlkyl Bromide Weight of Alkoxycinnamic AcidFormula Weight p-Hydroxycinnamic Acid Formula Weight__________________________________________________________________________CH.sub.3 (CH.sub.2).sub.5 Br 3.30 g. 3.28 g. ##STR34## 2.04 g.CH.sub.3 (CH.sub.2).sub.7 Br 3.86 g. 3.28 g. ##STR35## 2.75 g.CH.sub.3 (CH.sub.2).sub.9 Br 4.42 g. 3.28 g. ##STR36## 1.48 g.__________________________________________________________________________
TABLE 6__________________________________________________________________________Preparation of Alkoxyphenoxyacetic Acids Weight ofAlkyl Bromide p-Hydroxyphenoxyacetic Alkoxyphenoxyacetic AcidFormula Weight Acid Formula Weight (g)__________________________________________________________________________CH.sub.3 (CH.sub.2).sub.7 Br 3.86 g. 2.36 g. ##STR37## 3.4CH.sub.3 (CH.sub.2).sub.9 Br 4.42 g. 2.36 g. ##STR38## 3.8__________________________________________________________________________
TABLE 7__________________________________________________________________________Preparation of Alkoxynicotinic AcidsAlkyl Bromide Weight of Alkoxynicotinic AcidFormula Weight 6-Hydroxynicotinic Acid Formula Weight__________________________________________________________________________CH.sub.3 (CH.sub.2).sub.7 Br 3.86 g. 2.78 g. ##STR39## 3.6 g.CH.sub.3 (CH.sub.2).sub.11 Br 4.98 g 2.78 g. ##STR40## 2.4 g.__________________________________________________________________________
EXAMPLE 2
Table 8, below, gives the preparation of the 2,4,5-trichlorophenyl esters of a number of Formula IV acids, including the alkoxybenzoic acids shown in Table 1 and the (alkylthio)benzoic acids shown in Table 2. The compounds set forth in Table 8 are prepared according to the same general procedure. The following procedure is illustrative:
The alkoxybenzoic acid or (alkylthio)benzoic acid (1 mole), 2,4,5-trichlorophenol (1.1 mole), and N,N'-dicyclohexylcarbodiimide (1 mole) are dissolved in methylene chloride. The mixture is stirred at room temperature for 15-18 hours after which it is filtered. The filtrate is evaporated to dryness under reduced pressure, and the residue is crystallized from acetonitrile-water. The product is dried under vacuum.
TABLE 8______________________________________Preparation of 2,4,5-Trichlorophenyl Esters Weight of 2,4,- 5-Tri- chloro-Formula IV Acid phenyl Weight Ester Formula (g) (g)______________________________________ ##STR41## 6.18 5.32 ##STR42## 6.79 1.93 ##STR43## 3.06 2.20 ##STR44## 6.90 5.91 ##STR45## 6.43 7.98 ##STR46## 1.34 1.42 ##STR47## 1.8 2.5 ##STR48## 2.3 2.8 ##STR49## 3.75 4.72 ##STR50## 4.17 5.7 ##STR51## 4.59 5.0 ##STR52## 5.01 8.6 ##STR53## 2.12 1.91 ##STR54## 3.2 2.36 ##STR55## 2.64 2.86 ##STR56## 2.0 1.65 ##STR57## 1.8 1.73 ##STR58## 2.8 3.98 ##STR59## 2.36 2.82 ##STR60## 3.4 4.11 ##STR61## 2.73 2.01 ##STR62## 2.78 4.3 ##STR63## 1.45 0.826 ##STR64## 3.34 4.86 ##STR65## 2.22 2.6 ##STR66## 2.65 3.06 ##STR67## 2.0 2.84 ##STR68## 2.75 3.7 ##STR69## 2.8 2.7 ##STR70## 3.08 2.4 ##STR71## 2.5 2.6 ##STR72## 2.0 2.6______________________________________ *Commercially available
EXAMPLE 3
Table 9, below, gives the preparation of the derivatives of A30912A nucleus prepared from the 2,4,5-trichlorophenyl esters set forth in Table 8. The derivatives of A30912A nucleus set forth in Table 9 are prepared in general according to the following procedure:
To A30912A nucleus, dissolved in DMF (10-50 ml.), is added the 2,4,5-trichlorophenyl ester of the alkoxybenzoic acid or the (alkylthio)benzoic acid (1:2 molar ratio). The reaction mixture is stirred for 15-18 hours after which it is taken to dryness to give a residue. The residue is washed (two times each) with a mixture of diethyl ether (50 ml) and methylene chloride (50 ml). The washings are discarded. The remaining residue is dissolved in ethyl acetate-methanol (3:2, v/v) and is chromatographed on a 100 ml. silica gel (Woelm, 70-150 ml.) column using the aforesaid solvent system as the eluent. The fractions from the chromatography are monitored by TLC on silica gel (Merck) using ethyl acetate-methanol (3:2, v/v) as the solvent system. Fractions containing the desired product are combined, and solvent is removed to give the product as a residue. The product may be analyzed by reverse phase HPLC as follows: In the alkoxy examples and the C 12 and C 14 alkylthio examples, the sample is dissolved in H 2 O/CH 3 OH/CH.sub. 3 CN (1:2:2 v/v). The sample solution (1 mg/ml) is injected into a 1/4 in. by 12 in. stainless steel column packed with C 18 Micro Bondapak resin (Waters Associates, Milford, Mass.), and the column is eluted with a solvent system comprising H 2 O/CH 3 OH/CH 3 CN (1:2:2 v/v). In the C 8 and C 10 alkylthio examples, the solvent system is H 2 O/CH 3 OH/CH 3 CN (2:1:2 v/v). The elution is performed at a pressure of 1500 psi with a flow rate of 3 ml./minute using a Waters 600A pump (Waters Associates, Inc.) and chart speed of 0.2 in./minute. Eluent is monitored with a Varian Vari-Chrom UV detector at 230 nm. The products may also be analyzed by field desorption mass spectrometry (FDMS).
TABLE 9__________________________________________________________________________Preparation of Formula IIIDerivatives of A-30912A Nucleus ##STR73## Ester A30912A HPLCR.sup.1 of Formula III Reactant (mg) Nucleus (mg) Product (mg) M.sup.+ [Na].sup.+ Retention__________________________________________________________________________ (cm) ##STR74## 430 400 103 1052 0.95 ##STR75## 460 400 82 1080 1.55 ##STR76## 490 400 162 1107 3.50 ##STR77## 514 400 159 1135 6.6 ##STR78## 446 400 266 1068 2.45 ##STR79## 474 400 228 1096 5.15 ##STR80## 500 400 293 1124 2.5 ##STR81## 530 400 266 1152 4.1 ##STR82## 483 400 190 1083 11.2 ##STR83## 800 800 920 1052 1.6 ##STR84## 800 800 740 1080 3.4 ##STR85## 800 800 780 1108 8.8 ##STR86## 800 800 650 1136 23.7 ##STR87## 444 400 284 1066 2.2 ##STR88## 1000 400 178 1123 8.5 ##STR89## 886 400 282 1066 1.5 ##STR90## 500 400 262 1123 5.2 ##STR91## 888 400 230 1066 4.4 ##STR92## 600 400 245 1024 1.2 ##STR93## 662 400 230 1064 2.4 ##STR94## 854 400 301 1050 3.2 ##STR95## 910 400 98 1078 9.5 ##STR96## 918 400 260 1082 1.8 ##STR97## 488 400 280 1110 2.7 ##STR98## 430 400 352 1053 1.0 ##STR99## 487 400 270 1109 2.1 ##STR100## 800* 800 460 1036 3.6 ##STR101## 922 800 145 1083 1.0 ##STR102## 802 400 320 1024 1.0 ##STR103## 831 400 245 1038 1.2 ##STR104## 858 400 303 1052 2.6 ##STR105## 888 400 191 1066 2.1 ##STR106## 914 400 335 1081 1.2 ##STR107## 1030 400 360 1136 3.0__________________________________________________________________________ *p-(n-Octyl)benzoyl chloride (commercially available) was used in this case, reacting the acid chloride with the nucleus in pyridine at room temperature under nitrogen for 24 hours.
EXAMPLE 4
The following procedure illustrates the preparation of the compounds of Formula III wherein A is sulfonyl or sulfinyl.
A. Preparation of p-(Alkylsulfonyl)benzoic Acid 2,4,5-Trichlorophenyl Ester
To a solution of 2,4,5-trichlorophenyl p-(n-decylthio)benzoate (970 mg., 2 mmole) in methylene chloride (20 ml) cooled in an ice bath is added m-chloroperbenzoic acid (442 mg, 2.0 mmole). After allowing the reaction mixture to warm to room temperature (15 minutes), it is washed twice with 0.1 N sodium hydroxide (25 ml). The organic phase, after drying over anhyd. Na 2 SO 4 , is crystallized from acetonitrile. Weight of product: 470 mg. The product is reoxidized as described above using m-chloroperbenzoic acid (108 mg) in methylene chloride (20 ml) and a reaction time of 50 minutes. The product is purified as described above to give 260 mg. of product.
Analysis for C 23 H 27 O 4 Cl 3 S: Calculated: C, 54.61%; H, 5.38%. Found: C, 54.90%; H, 5.45%.
Other p-(alkylsulfonyl)benzoic acid 2,4,5-trichlorophenyl esters can be prepared by the above-described methods as shown below:
______________________________________p-Alkylsulfonyl Wt. of Wt. ofbenzoic acid 2,4,5- ester (mg) oxidizing Wt. oftrichlorophenyl ester reactant agent (mg) product (mg)______________________________________n-octyl 850 451 68.8n-dodecyl 1260 686 400n-tetradecyl 1150 651 400______________________________________
B. Acylation of A-30912A Nucleus
A solution of A-30912A nucleus (400 mg., 0.5 mmole) and p-(n-decylsulfonyl)benzoic acid 2,4,5-trichlorophenyl ester (260 mg., 0.514 mmole) in dimethylformamide (50 ml.) is allowed to stir at room temperature for 18 hours. The reaction mixture is evaporated to dryness in vacuo, and the residue is extracted twice with diethyl ether and methylene chloride. The residue, dissolved in a minimum amount of an ethyl acetate-methanol mixture (3:2, v/v), is then applied to a silica gel column (50 ml.) and eluted with the same solvent mixture. The course of the chromatography is followed by TLC on silica gel (Merck) using ethyl acetate-methanol (3:2) as the solvent system. Fractions containing the desired product (R f ≅0.6) are combined, evaporated to dryness, and lyophilized. Weight of p-(n-decylsulfonyl)benzoyl derivative of A-30912A nucleus: 415 mg. Field desorption mass spectral analysis shows (M + +23)=1128. Analytical HPLC shows the product to be a single component.
Following the above procedure, other p-(alkylsulfonyl)benzoyl derivatives of A-30912A nucleus can be made as shown below:
______________________________________p-Alkylsulfonyl Wt. of Wt. of Wt. ofbenzoyl nucleus ester reactant productderivative (mg) (mg) (mg) M.sup.+ [Na].sup.+______________________________________ 4n-octyl 400 69 83 --n-dodecyl 400 267 335 1156n-tetradecyl 400 281 322 1184______________________________________
C. Preparation of p-(Alkylsulfinyl)benzoic Acid 2,4,5-Trichlorophenyl Ester
To a solution of 2,4,5-trichlorophenyl p-(n-octylthio)benzoate (2.23 g, 5 mmole) in methylene chloride (50 ml) cooled in an ice bath is added dropwise a solution of m-chloroperbenzoic acid (1.39 g, 8 mmole, in 50 ml of methylene chloride). The solution is stirred at 5° C. for about 2 hours and then at room temperature for about 2 hours. After adding 2-3 drops of 20% Na 2 SO 3 solution, the reaction mixture is washed once with 10% NaHCO 3 solution and twice with water. The organic layer is dried (MgSO 4 ) and concentrated under vacuum to give a residue which is crystallized from diethyl ether:petroleum ether (1:4) to give 1.7 g of product which is a mixture of the sulfinyl and the sulfonyl compounds.
D. Acylation of A-30912A Nucleus
A solution of A-30912A nucleus (800 mg, 1 mmole) in DMF (25 ml) is reacted with the product obtained in Sect. C (922 mg, 2 mmole) as described in Sect. B to give 952 mg of mixed product. This product is chromatographed over silica gel (100 g of 100-200 mesh), using an ethyl acetate:methanol (3:2) solvent system. The first fractions obtained from this column (554 mg) are rechromatographed over silica gel, using ethyl acetate to which increasing amounts of methanol are added as the eluting solvent. Fractions are combined on the basis of TLC results. After elution of the p-(n-octylsulfonyl)benzoyl derivative of A-30912A nucleus (58 mg), the p-(n-octylsulfinyl)benzoyl derivative of A-30912A nucleus is eluted to give 145 mg of product.
EXAMPLE 5
The following procedure illustrates the large-scale preparation of the compounds of Formula III. The specific compound prepared by the procedure given below is the compound of formula III wherein R 1 is p-(n-octyloxy)benzoyl.
A. Preparation of p-(n-Octyloxy)benzoic Acid
A solution of p-hydroxybenzoic acid (19.2 g., 150 mmole) in 10% aqueous sodium hydroxide (120 ml.) is added to DMSO (480 ml.) previously heated to 80° C. n-Octyl bromide (28.95 g., 150 mmole) is added dropwise to the solution. The reaction mixture is stirred for 4 hours at room temperature after which it is poured into ice water (1200 ml.). Conc. hydrochloric acid (30 ml.) is added, and the mixture is allowed to stand until precipitation is complete. The precipitate is collected, dried, and crystallized from acetonitrile-water. m.p. 97°-99° C.
Analysis for C 15 H 22 O 3 : Calculated: C, 71.97; H, 8.86. Found: C, 71.72; H, 9.10.
B. Preparation of the 2,4,5-Trichlorophenyl Ester of p-(n-Octyloxy)benzoic Acid
p-(n-Octyloxy)benzoic acid (6.18 g., 24.7 mmole), 2,4,5-trichlorophenol (5.39 g., 27.2 mmole) and N,N'-dicyclohexylcarbodiimide (4.94 g., 24.7 mM) are dissolved in methylene chloride (200 ml.). The mixture is stirred at room temperature for 18 hours and then is filtered. The filtrate is evaporated to give an oil, which is crystallized from CH 3 CN--H 2 O to give the 2,4,5-trichlorophenyl ester of p-(n-octyloxy)benzoic acid.
NMR Analysis: δ4.02 (2H, t, J=3 Hz), δ7.0 (1H, d, J=4 Hz), 7.23 (s, 1H), 7.3 (s, 1H), 8.08 (d, 1H, J=4 Hz).
C. Acylation of A-30912A Nucleus
A-30912A nucleus (14.2 g., 17.8 mmole) and the 2,4,5-trichlorophenyl ester of p-(n-octyloxy)benzoic acid (15.32 g., 35.7 mmole) are dissolved in dimethylformamide (150 ml.). The solution is stirred at room temperature for 16-20 hours. Solvent is removed in vacuo, and the residue is washed twice with diethyl ether and twice with methylene chloride. The washes are discarded. The washed residue is dissolved in 25% ethyl acetate-methanol (80 ml.) and is purified by high performance liquid chromatography using a "Prep LC/System 500" unit (Waters Associates, Inc., Milford, Mass.) employing silica gel as the stationary phase. The column is eluted stepwise with 20% to 40% methanol-ethyl acetate solvent systems. The fractions are analyzed by TLC using silica gel (Merck) and ethyl acetate-methanol (3:2 v/v) as the solvent system. Fractions devoid of A-30912A nucleus are pooled and lyophilized to give the p-(n-octyloxy)benzoyl derivative of A-30912A nucleus. Yield: 7.13 g.; M + +23: 1052 (by FDMS).
EXAMPLE 6
The antifungal activity of the compounds of Formula III can be demonstrated and elicited in vitro in standard disc-diffusion tests and agar dilution tests, and in vivo in standard tests in mice which assess effectiveness against a systemic fungal infection. The results of the antifungal testing of representative compounds of Formula III (Examples 3 and 4) are set forth in Tables 10, 11, 12, and 13.
Tables 10 and 11 give the results of the testing in vitro of the compounds of Examples 3 and 4 by agar-plate disc-diffusion methods. In Table 10 activity is measured by the size (diameter in mm) of the observed zone of inhibition of the microorganism produced by the test compound. In Table 11, activity is measured by the minimal inhibitory concentration (MIC) of the substance (μg/disc) required to inhibit growth of the test organism. Table 12 gives the results of the testing in vitro of the p-(n-octyloxy)benzoyl derivative of A30912A nucleus [Formula III, R 1 is p-(n-octyloxy)benzoyl] against five strains of Candida albicans by the agar dilution method. In Table 12 activity is measured by the minimal inhibitory concentration (MIC) of the substance (μg/ml) required to inhibit the test organism.
The results of in vivo tests to evaluate the effectiveness of the compounds of Examples 3 and 4 against an infection caused by Candida albicans A-26 in mice are given in Table 13, where activity is measured by the ED 50 value (the dose in mg/kg. required to cure 50% of the test animals). In a separate test, the results of which are also summarized in Table 13, activity is indicated by the lowest dose at which a significant anti-fungal effect is observed. In this test, groups of male albino mice (specific pathogen free), weighing 18 to 20 grams, are infected intravenously with Candida albicans A-26. The animals are X-irradiated 24 hours prior to infection at about 50 roentgens per minute for 8 minutes (400 total dose) to reduce immune responses to the infecting organism. At 0, 4, and 24 hours post infection each group of mice is given graded doses subcutaneously of the test compound as a suspension in 33% polyethylene glycol (PEG)-water. The day of death for each animal is recorded. Student's test statistical comparison of the average day of death is made between each group of infected-treated animals at a particular dosage level and 10 infected-untreated animals to determine if treatment significantly extends survival time.
Table 14 gives the results of the testing of the compounds of Example 3 and 4 for absorption after oral administration. In this test, mice are gavaged with a dose of 416 mg/kg of the test compound suspended in 33% PEG 400-water. At time intervals, blood samples are taken from the orbital sinus and are assayed for antibiotic activity as follows: A 7 mm. disc containing 20 μl of whole blood is placed on agar seeded with Aspergillus montevidensis A35137. After 40 hours incubation at 30° C. zones of inhibition from the blood samples are compared to a standard obtained from the test compound, and the amount of compound in the blood sample is calculated.
TABLE 10__________________________________________________________________________Antifungal Activity By the Agar Plate Disc Diffusion Test Size of Zone of Inhibition (mm).sup.(a)Compound Saccharomyces Neurospora Trichophyton CandidaR.sup.1 of Formula III pastoranius X-52 crassa 846 mentagraphytes A-23 albicans A-26__________________________________________________________________________ ##STR108## 18 23* -- 28 ##STR109## 13 -- -- 18 ##STR110## 13 24* -- 19 ##STR111## 20 15 19* 19 ##STR112## 16 31 32 55 ##STR113## -- 37 26 48 ##STR114## 23 29 23 30__________________________________________________________________________ .sup.(a) Compounds were tested as suspension in methanol. The compounds were tested at a concentration of 1 mg/ml. by dipping a 7mm disc into the suspension and placing it on the agar surface. Incubation: 24-48 hours at 25-37° C. *Measurable zone of inhibition with regrowth of organism around disc.
TABLE 11__________________________________________________________________________Antifungal Activity By the Agar Plate Disc Diffusion Test MIC (μg/disc).sup.(a)Compound TrychophytonR.sup.1 of Formula III Candida albicans A-26 mentagrophyes #6*__________________________________________________________________________ ##STR115## 0.156 <0.039 ##STR116## 0.156 <0.078 ##STR117## 2.5 <0.039 ##STR118## 0.625 <0.078 ##STR119## 0.312 <0.039 ##STR120## 0.156 0.039 ##STR121## 2.5 <0.039 ##STR122## 20.0 <0.039 ##STR123## 20 0.312 ##STR124## 2.5 0.156 ##STR125## 0.625 0.078 ##STR126## 0.625 0.039 ##STR127## 10 >40 ##STR128## 2.5 >40 ##STR129## 2.5 >40 ##STR130## 40 40 ##STR131## 2.5 0.312 ##STR132## 5 1.25 ##STR133## 0.625 0.156 ##STR134## 20 1.25 ##STR135## 0.625 0.156 ##STR136## 0.078 0.156 ##STR137## 0.312 0.156 ##STR138## 1.25 40 ##STR139## 1.25 0.156 ##STR140## 0.156 0.156 ##STR141## 5 80 ##STR142## 0.312 0.625 ##STR143## 5 0.156 ##STR144## 0.625 0.156 ##STR145## 0.312 80 ##STR146## 0.156 <0.156 ##STR147## 80 2.5__________________________________________________________________________ .sup.(a) Compounds were suspended in 0.1M sodium borate solution, pH 7.5. The compounds were tested at 20 μg/disc at top level and at twofold dilutions until end points were reached. Incubation: 24 hours; 30° C. *Measurable zones of inhibition with regrowth of organism around disc.
TABLE 12__________________________________________________________________________In vitro activity of derivatives of A-30912A nucleusagainst 5 strains of Candida albicansCompound MIC (μg/ml.)R.sup.1 of Formula III A-26 SBH16 SBH31 SBH28 SBH29__________________________________________________________________________ ##STR148## 0.312 0.312 0.312 0.312 0.312 ##STR149## 0.625 0.625 0.625 0.625 0.625 ##STR150## 2.5 2.5 2.5 2.5 2.5__________________________________________________________________________
TABLE 13______________________________________Therapeutic Activity Against Candida Albicans A-26 in Mice* Lowest ED.sub.50 ActiveCompound (mg/- DoseR.sup.1 of Formula III kg)** (mg/kg)______________________________________ ##STR151## 13 22.2 10 <12.5 ##STR152## 8 5 ##STR153## <5 3.9 ≦5 2.5 ##STR154## 3 5 ##STR155## 37.4 10 ##STR156## 28 20 ##STR157## 2 <1.25 ##STR158## 20 2.5 ##STR159## 57 -- ##STR160## 57 -- ##STR161## 53 20 ##STR162## 11 5 ##STR163## >50 40 ##STR164## >50 >40 ##STR165## >50 >40 ##STR166## >50 >40 ##STR167## 28 20 ##STR168## 56.6 >40 ##STR169## 30 40 ##STR170## >40 40 ##STR171## 9.2 5 ##STR172## 4.5 ##STR173## 4.5 ##STR174## >40 20 ##STR175## 21.8 5 ##STR176## 3.75 5 ##STR177## >40 10 ##STR178## 8.4 10 ##STR179## 16.8 10 ##STR180## 7.4 20______________________________________ *Dosage Schedules: A. = 40, 20, 15 and 10 mg/kg; Dosages given 0, 4, and 24 hours post injection as suspension of test compound in 30% PEGH.sub.2 O. Number of mice receiving test compounds at each dosage level: 6 mice per group. Number of mice in control (untreated) group: 10 mice per group **As measured by increase in survival time of treated animals versus control, calculated by method of Reed v Mueuch, American J. Hygiene, 27, 493 (1938).
TABLE 14______________________________________Blood Levels After Oral Administration In Mice Highest Blood Level Determined DuringCompound a 4-Hour Time IntervalR.sup.1 of Formula III (μg/ml.)______________________________________ ##STR181## 23 ##STR182## <0.1 ##STR183## 5 ##STR184## 5 ##STR185## <0.1 ##STR186## 5 ##STR187## 30 ##STR188## 230______________________________________ *Test compound administered at dose of 416 mg/kg by gavage as suspension of compound in 33% PEG 400H.sub.2 O. Antifungal activity determined by bioassay vs. Aspergillus montevidensis A35137.
EXAMPLE 7
Preparation of A-30912A Nucleus
A. Fermentation of Actinoplanes utahensis NRRL 12052
A stock culture of Actinoplanes utahensis NRRL 12052 is prepared and maintained on an agar slant. The medium used to prepare the slant is selected from one of the following:
______________________________________MEDIUM AIngredient Amount______________________________________Baby oatmeal 60.0 gYeast 2.5 gK.sub.2 HPO.sub.4 1.0 gCzapek's mineral stock* 5.0 mlAgar 25.0 gDeionized water q.s. to 1 liter______________________________________pH before autoclaving is about 5.9; adjust to pH 7.2 byaddition of NaOH; after autoclaving, pH is about 6.7.*Czapek's mineral stock has the following composition:Ingredient Amount______________________________________FeSO.sub.4 . 7H.sub.2 O (dissolved in2 ml conc HCl) 2 gKCl 100 gMgSO.sub.4 . 7H.sub.2 O 100 gDeionized water q.s. to 1 liter______________________________________MEDIUM BIngredient Amount______________________________________Potato dextrin 5.0 gYeast extract 0.5 gEnzymatic hydrolysate of casein* 3.0 gBeef extract 0.5 gDextrose 12.5 gCorn starch 5.0 gMeat peptone 5.0 gBlackstrap molasses 2.5 gMgSO.sub.4 . 7H.sub.2 O 0.25 gCaCO.sub.3 1.0 gCzapek's mineral stock 2.0 mlAgar 20.0 gDeionized water q.s. to 1 liter______________________________________ *N-Z-Amine A, Humko Sheffield Chemical, Lyndhurst, N.J.
The slant is inoculated with Actinoplanes utahensis NRRL 12052, and the inoculated slant is incubated at 30° C. for about 8 to 10 days. About 1/2 of the slant growth is used to inoculate 50 ml of a vegetative medium having the following composition:
______________________________________Ingredient Amount______________________________________Baby oatmeal 20.0 gSucrose 20.0 gYeast 2.5 gDistiller's Dried Grain* 5.0 gK.sub.2 HPO.sub.4 1.0 gCzapek's mineral stock 5.0 mlDeionized water q.s to 1 liter______________________________________ adjust to pH 7.4 with NaOH; after autoclaving, pH is about 6.8. *National Distillers Products Co., 99 Park Ave., New York, N.Y.
The inoculated vegetative medium is incubated in a 250-ml wide-mouth Erlenmeyer flask at 30° C. for about 72 hours on a shaker rotating through an arc two inches in diameter at 250 RPM.
This incubated vegetative medium may be used directly to inoculate a second-stage vegetative medium. Alternatively and preferably, it can be stored for later use by maintaining the culture in the vapor phase of liquid nitrogen. The culture is prepared for such storage in multiple small vials as follows: In each vial is placed 2 ml of incubated vegetative medium and 2 ml of a glycerol-lactose solution [see W. A. Dailey and C. E. Higgens, "Preservation and Storage of Microorganisms in the Gas Phase of Liquid Nitrogen, Cryobiol 10, 364-367 (1973) for details]. The prepared suspensions are stored in the vapor phase of liquid nitrogen.
A stored suspension (1 ml) thus prepared is used to inoculate 50 ml of a first-stage vegetative medium (having the composition earlier described). The inoculated first-stage vegetative medium is incubated as above-described.
In order to provide a larger volume of inoculum, 10 ml of the incubated first-stage vegetative medium is used to inoculate 400 ml of a second-stage vegetative medium having the same composition as the first-stage vegetative medium. The second-stage medium is incubated in a two-liter wide-mouth Erlenmeyer flask at 30° C. for about 48 hours on a shaker rotating through an arc two inches in diameter at 250 RPM.
Incubated second-stage vegetative medium (800 ml), prepared as above-described, is used to inoculate 100 liters of sterile production medium selected from one of the following:
______________________________________MEDIUM IIngredient Amount (g/L)______________________________________Peanut meal 10.0Soluble meat peptone 5.0Sucrose 20.0KH.sub.2 PO.sub.4 0.5K.sub.2 HPO.sub.4 1.2MgSO.sub.4 . 7H.sub.2 O 0.25Tap water q.s to 1 liter______________________________________
The pH of the medium is about 6.9 after sterilization by autoclaving at 121° C. for 45 minutes at about 16-18 psi.
______________________________________MEDIUM IIIngredient Amount (g/L)______________________________________Sucrose 30.0Peptone 5.0K.sub.2 HPO.sub.4 1.0KCl 0.5MgSO.sub.4 . 7H.sub.2 O 0.5FeSO.sub.4 . 7H.sub.2 O 0.002Deionized water q.s. to 1 liter______________________________________
Adjust to pH 7.0 with HCl; after autoclaving, pH is about 7.0.
______________________________________MEDIUM IIIIngredient Amount (g/L)______________________________________Glucose 20.0NH.sub.4 Cl 3.0Na.sub.2 SO.sub.4 2.0ZnCl.sub.2 0.019MgCl.sub.2 . 6H.sub.2 O 0.304FeCl.sub.3 . 6H.sub.2 O 0.062MnCl.sub.2 . 4H.sub.2 O 0.035CuCl.sub.2 . 2H.sub.2 O 0.005CaCO.sub.3 6.0KH.sub.2 PO.sub.4 * 0.67Tap water q.s to 1 liter______________________________________
Final pH about 6.6.
The inoculated production medium is allowed to ferment in a 165-liter fermentation tank at a temperature of about 30° C. for about 42 hours. The fermentation medium is stirred with conventional agitators at about 200 RPM and aerated with sterile air to maintain the dissolved oxygen level above 30% of air saturation at atmospheric pressure.
B. Deacylation of A-30912A
A fermentation of A. utahensis is carried out as described in Sect. A, using slant medium A and production medium I and incubating the production medium for about 42 hours. A-30912 factor A (340 g. of crude substrate which contained about 19.7 g. of A-30912 factor A, dissolved in 1.5 L ethanol) is added to the fermentation medium. Deacylation of A-30912 factor A is monitored by assay against Candida albicans. The fermentation is allowed to continue until deacylation is complete as indicated by disappearance of activity vs. C. albicans.
C. Isolation of A-30912A Nucleus
Whole fermentation broth (100 liters), obtained as described in Sect. B and containing nucleus from about 20 g of A-30912 factor A, is filtered. The mycelial cake is discarded. The clear filtrate thus obtained (about 93 liters) is passed through a column containing 4.5 liters of HP-20 resin (DIAION High Porous Polymer, HP-Series, Mitsubishi Chemical Industries Limited, Tokyo, Japan) at a rate of 200 ml/minute. The effluent thus obtained is discarded. The column is then washed with up to eight column volumes of deionized water at pH 6.5-7.5 to remove residual filtered broth. This wash water is discarded. The column is then eluted with a water:methanol (7:3) solution (85 liters) at a rate of 200-300 ml/minute.
Elution is monitored using the following procedure: Two aliquots are taken from each eluted fraction. One of the aliquots is concentrated to a small volume and is treated with an acid chloride such as myristoyl chloride. This product and the other (untreated) aliquot are assayed for activity against Candida albicans. If the untreated aliquot does not have activity and the acylated aliquot does have activity, the fraction contains A-30912A nucleus. The eluate containing the A-30912A nucleus is concentrated under vacuum to a small volume and lyophilized to give approximately 97 grams of crude nucleus.
D. Purification of A-30912A Nucleus by Reversed-Phase Liquid Chromatography
Crude A-30912A nucleus (25 grams), obtained as described in Section C, is dissolved in 300 ml of water:acetonitrile:acetic acid:pyridine (96:2:1:1). This solution is chromatographed on a 4-liter stainless-steel column (8 cm×80 cm) filled with Lichroprep RP-18, particle size 25-40 microns (MC/B Manufacturing Chemists, Inc. E/M, Cincinnati, OH). The column is part of a Chromatospac Prep 100 unit (Jobin Yvon, 16-18 Rue du Canal 91160 Longjumeau, France). The column is operated at a pressure of 90-100 psi, giving a flow rate of about 60 ml/minute, using the same solvent. Separation is monitored at 280 nm using a UV monitor (ISCO Absorption Monitor Model UA-5, Instrumention Specialties Co., 4700 Superior Ave., Lincoln, Nebr. 68504) with an optical unit (ISCO Type 6). Fractions having a volume of about 500 ml are collected each minute.
On the basis of absorption at 280 nm, fractions containing A-30912A nucleus are combined, evaporated under vacuum and lyophilized to give 2.6 grams of nucleus. The amount of solvent required to complete this chromatographic separation process varies from 7-8 liters.
A30912A nucleus has the following characteristics:
(a) Empirical formula: C 34 H 51 N 7 O 15 .
(b) Molecular weight: 779.
(c) Soluble in water, dimethylformamide, dimethyl sulfoxide, and methanol; insoluble in chloroform, toluene, and diethyl ether.
(d) Infrared absorption spectrum (KBr disc.
Shows absorption maxima at: 3340 broad (OH, H-bonded); 2970, 2930, and 2890 (CH); 1625 (several carbonyls C═O); 1510-1550; 1430-1450 (CH wag); 1310-1340; 1230-1260; 1080; 835, 650 broad, and 550 broad cm -1 .
(e) Electrometric titration in 66% aqueous dimethylformamide indicates the presence of a titratable group with a pK a value of about 7.35 (initial pH 7.32).
(f) HPLC retention time (K'):11.52 min. under following conditions.
Column: 4×300 mm
Packing: silica gel/C 18
Solvent: ammonium acetate:acetonitrile:water (1:2:97)
Flow Rate: 3 ml/min
Pressure: 2500 psi
Detector: variable wavelength UV at 230 nm
Sensitivity: 0-0.4 A.U.F.S.
EXAMPLE 8
A-30912A nucleus is prepared and purified by the method of Example 7 except that tetrahydro-A-30912A is used as the substrate in Sect. B.
EXAMPLE 9
A-30912A nucleus is prepared and purified by the method of Example 7 except that aculeacin A is used as the substrate in Sect. B.
EXAMPLE 10
Preparation of the A-42355 Antibiotic Complex
A. Shake-Flask Fermentation
A culture of Aspergillus nidulans var. roseus NRRL 11440 is prepared and maintained on an agar slant prepared with sodium having the following composition.
______________________________________Ingredient Amount______________________________________Glucose 5 gYeast extract 2 gCaCO.sub.3 3 gVegetable juice* 200 mlAgar** 20 gDeionized water q.s to 1 liter______________________________________ (initial pH 6.1) *V-8 Juice, Campbell Soup Co., Camden, N.J. **Meer Corp.
The slant is inoculated with Aspergillus nidulans var. roseus NRRL 11440, and the inoculated slant is incubated at 25° C. for about seven days. The mature slant culture is covered with water and scraped with a sterile loop to loosen the spores. The resulting suspension is further suspended in 10 ml of sterile deionized water.
One ml of the suspended slant growth is used to inoculate 55 ml of vegetative medium in a 250-ml flask. The vegetative medium has the following composition:
______________________________________Ingredient Amount______________________________________Sucrose 25 gBlackstrap molasses 36 gCorn-steep liquor 6 gMalt extract 10 gK.sub.2 HPO.sub.4 2 gEnzymatic hydrolysateof casein* 10 gTap water 1100 ml______________________________________ (initial pH 6.5-6.7) *N-Z-Case, Humko Sheffield Chemical, Lyndhurst, N.J.
The inoculated vegetative medium is incubated at 25° C. for 48 hours at 250 rpm on a rotary-type shaker. After 24 hours, the medium is homogenized for one minute at low speed in a blender (Waring type) and then returned to incubation for the remaining 24 hours. Alternatively, the inoculated vegetative medium can be incubated for 48 hours and then homogenized for 15 seconds at low speed.
This incubated vegetative medium may be used to inoculate shake-flask fermentation culture medium or to inoculate a second-type vegetative medium. Alternatively, it can be stored for later use by maintaining the culture in the vapor phase of liquid nitrogen. The culture is prepared for such storage in multiple small vials as follows: The vegetative cultures are mixed volume/volume with a suspending solution having the following composition:
______________________________________Ingredient Amount______________________________________Glycerol 20 mlLactose 10 gDeionized water q.s. to 100 ml______________________________________
The prepared suspensions are distributed in small sterile screw-cap tubes (4 ml per tube). These tubes are stored in the vapor phase of liquid nitrogen.
A stored suspension thus prepared can be used to inoculate either agar slants or liquid seed media. Slants are incubated at 25° C. in the light for 7 days.
B. Tank Fermentation
In order to provide a larger volume of inoculum, 10 ml of incubated first-stage vegetative culture is used to inoculate 400 ml of a second-stage vegetative growth medium having the same composition as that of the vegetative medium. The second-stage medium is incubated in a two-liter wide-mouth Erlenmeyer flask at 25° C. for 24 hours on a shaker rotating through an arc two inches in diameter at 250 rpm.
Incubated second-stage medium (800 ml), prepared as above described, is used to inoculate 100 liters of sterile production medium selected from one of the following:
______________________________________MEDIUM IVIngredient Amount______________________________________ZnSO.sub.4 . 7H.sub.2 O 0.00455 g/LSoluble meat peptone* 30.5 g/LSoybean meal 15.5 g/LTapioca dextrin** 2.0 g/LBlackstrap molasses 10.5 g/LEnzymatic hydrolysateof casein*** 8.5 g/LNa.sub.2 HPO.sub.4 4.5 g/LMgSO.sub.4 . 7H.sub.2 O 5.5 g/LFeSO.sub.4 . 7H.sub.2 O 0.1 g/LCottonseed oil 40.0 ml(Antifoam)**** 1.0 mlTap water 1000.0 ml______________________________________ (initial pH 6.8-7.0) *O.M. Peptone, Amber Laboratories, Juneau, Wisc. **Stadex 11, A.E. Staley Co., Decatur, Ill. ***N-Z-Amine A, Humko Sheffield Chemical, Lyndhurst, N.J. ****P2000, Dow Corning, Midland, Michigan
MEDIUM VIngredient Amount______________________________________Glucose 2.5%Starch 1.0%Soluble meat peptone* 1.0%Blackstrap molasses 1.0%CaCO.sub.3 0.2%MgSO.sub.4 . 7H.sub.2 O 0.05%Enzymatic hydrolysate ofcasein** 0.4%(Antifoam)*** 0.02%Tap water q.s. to volume______________________________________ *O.M. Peptone **N-Z-Amine A ***Antifoam "A" Dow Corning
the inoculated production medium is allowed to ferment in a 165-liter fermentation tank at a temperature of 25° C. for about 7 days. The fermentation medium is aerated with sterile air, maintaining the dissolved oxygen level above approximately 50 percent of air saturation.
C. Third-Stage Vegetative Medium
Whenever the fermentation is carried out in tanks larger than those used for 100-liter fermentation, it is recommended that a third-stage vegetative culture be used to seed the larger tank. A preferred third-stage vegetative medium has the following composition:
______________________________________Ingredient Amount______________________________________Sucrose 25 gBlackstrap molasses 25 gCorn-steep liquor 6 gEnzymatic hydrolysateof casein* 10 gMalt extract 10 gK.sub.2 HPO.sub.4 2 gTap water 1000 ml______________________________________ (initial pH 6.1) *N-Z-Case
EXAMPLE 11
Separation of the A-42355 Antibiotic Complex
Whole fermentation broth (4127 liters), obtained by the method described in Example 10 using production medium V, is stirred thoroughly with methanol (4280 liters) for one hour and then is filtered, using a filter aid (Hyflo Super-cel, a diatomaceous earth, Johns-Manville Products Corp.). The pH of the filtrate is adjusted to pH 4.0 by the addition of 5 N HCl. The acidified filtrate is extracted twice with equal volumes of chloroform. The chloroform extracts are combined and concentrated under vacuum to a volume of about 20 liters. This concentrate is added to about 200 liters of diethyl ether to precipitate the A-42355 complex. The precipitate is separated by filtration to give 2775 g of the A-42355 complex as a gray-white powder.
EXAMPLE 12
Isolation of A-30912 Factor A
The co-pending application of Karl H. Michel entitled RECOVERY PROCESS FOR A-30912 ANTIBIOTICS, Ser. No. 103,014, filed Dec. 13, 1979, describes the reversed-phase high performance, low pressure liquid chromatography (HPLPLC) using silica gel/C 18 adsorbent as a preferred method for the final purification of A-30912 factor A.
A-42355 antibiotic complex (1 g), prepared as described in Example 11, is dissolved in 7 ml of methanol:water:acetonitrile (7:2:1). This solution is filtered and introduced onto a 3.7-cm I.D.×35-cm glass column [Michel-Miller High Performance Low Pressure (HPLPLC) Chromatography Column, Ace Glass Incorporated, Vineland, NJ 08360] packed with LP-1/C 18 silica gel reversed-phase resin (10-20 microns), prepared as described in Example 13, through a loop with the aid of a valve system. The column is packed in methanol:water:acetonitrile (7:2:1) by the slurry-packing procedure described in Example 14. An F.M.I. pump with valveless piston design (maximum flow 19.5 ml/minute) is used to move the solvent through the column at a flow rate of 9 ml/minute at ca. 100 psi, collecting fractions every minute. Elution of the antibiotic is monitored at 280 nm by using a UV monitor (ISCO Model UA-5, Instrument Specialist Co., 4700 Superior Ave., Lincoln, Nebr. 68504) with an optical unit (ISCO Type 6).
The individual A-30912 factors can be identified by the use of thin-layer chromatography (TLC). The R f values of A-30912 factors A-G, using silica gel (Merck, Darmstadt) TLC, a benzene:methanol (7:3) solvent system, and Candida albicans bioautography are given in Table 15.
TABLE 15______________________________________A-30912 Factor R.sub.f Value______________________________________A 0.35B 0.45C 0.54D 0.59E 0.27F 0.18G 0.13______________________________________
The approximate R f values of A-30912 factors A, B, C, D, and H in different solvent systems, using silica gel TLC (Merck-Darmstadt silica gel #60 plates, 20×20 cm) and Candida albicans bioautography, are given in Table 16.
TABLE 16______________________________________ R.sub.f Values - Solvent SystemsA-30912 Factor a b c d______________________________________Factor A 0.28 0.14 0.28 0.43Factor B 0.39 0.21 0.42 0.47Factor C 0.46 0.31 0.51 0.58Factor D 0.50 0.38 0.57 0.61Factor H 0.42 0.27 0.36 0.53______________________________________ Solvent Systems a ethyl acetate:methanol (3:2) b ethyl acetate:methanol (7:3) c acetonitrile:water (95:5) d ethyl acetate:ethanol:acetic acid (40:60:0.25)
A-30912 factors A, B, D and H can also be indentified by analytical HPLPLC using the following conditions:
______________________________________Column: glass, 0.8 × 15.0 cmPacking: Nucleosil® 10-C.sub.18 (Machery- Nagel and Company); packed using slurry-packing pro- cedure of Example 8Solvent: methanol:water:aceto- nitrile (7:2:1)Sample Volume: 8 mclSample Size: 8 mcgColumn Temperature: ambientFlow Rate: 1.8 ml/minPressure: ca. 200 psiDetector: UV at 222 nm (ISCO Model 1800 Variable Wavelength UV-Visible Absorbance Monitor)Pump: LDC Duplex MinipumpInjection: loop injection______________________________________
The approximate retention times for A-30912 factors A, B, D, and H under these conditions are summarized in Table 17.
TABLE 17______________________________________ Retention TimeA-30912 Factor (seconds)______________________________________A 792B 870H 990D 1,140______________________________________
EXAMPLE 13
Preparation of Silica Gel/C 18 Reversed Phase Resin
Step 1: Hydrolysis
LP-1 silica gel (1000 g from Quantum Corp., now Whatman) is added to a mixture of concentrated sulfuric acid (1650 ml) and concentrated nitric acid (1650 ml) in a 5-L round-bottom flask and shaken for proper suspension. The mixture is heated on a steam bath overnight (16 hours) with a water-jacketed condenser attached to the flask.
The mixture is cooled in an ice bath and carefully filtered using a sintered-glass funnel. The silica gel is washed with deionized water until the pH is neutral. The silica gel is then washed with acetone (4 L) and dried under vacuum at 100° C. for 2 days.
Step 2: First Silylation
The dry silica gel from Step 1 is transferred to a round-bottom flask and suspended in toluene (3.5 L). The flask is heated on a steam bath for 2 hours to azeotrope off some residual water. Octadecyltrichlorosilane (321 ml, Aldrich Chemical Company) is added, and the reaction mixture is refluxed overnight (16 hours) with slow mechanical stirring at about 60° C. Care is taken so that the stirrer does not reach near the bottom of the flask. This is to prevent grinding the silica gel particles.
The mixture is allowed to cool. The silanized silica gel is collected, washed with toluene (3 L) and acetone (3 L), and then air-dried overnight (16-20 hours). The dried silica gel is suspended in 3.5 L of acetonitrile:water (1:1) in a 5-L flask, stirred carefully at room temperature for 2 hours, filtered, washed with acetone (3 L) and air-dried overnight.
Step 3: Second Silylation
The procedure from the first silylation is repeated using 200 ml of octadecyltrichlorosilane. The suspension is refluxed at 60° C. for 2 hours while stirring carefully. The final product is recovered by filtration, washed with toluene (3 L) and methanol (6 L), and then dried under vacuum at 50° C. overnight (16-20 hours).
EXAMPLE 14
Slurry Packing Procedure for Michel-Miller Columns
General Information
This procedure is employed for packing reversed phase silica gel C 18 resin, such as that described in Example 13.
Generally, a pressure of less than 200 psi and flow rates between 5-40 ml/minute are required for this slurry packing technique; this is dependent on column volume and size. Packing pressure should exceed the pressure used during actual separation by 30-50 psi; this will assure no further compression of the adsorbent during separation runs.
A sudden decrease in pressure may cause cracks or channels to form in the packing material, which would greatly reduce column efficiency. Therefore, it is important to let the pressure drop slowly to zero whenever the pump is turned off.
The approximate volume of columns (Ace Glass Cat. No., unpacked) are No. 5795-04, 12 ml; No. 5795-10, 110 ml; No. 5795-16, 300 ml; No. 5795-24, 635 ml; and No. 5796-34, 34 ml.
The time required to pack a glass column will vary from minutes to several hours depending on column size and the experience of the scientist.
Example
1. Connect glass column to a reservoir column via coupling (volume of reservoir column should be twice that of the column). Place both columns in vertical positions (reservoir column above).
2. Weigh out packing material (ca. 100 g for 200 ml column).
3. Add ca. five volumes of solvent to packing material; use a mixture of 70-80% methanol and 20-30% water.
4. Shake well until all particles are wetted, let stand overnight or longer to assure complete soaking of particles by solvent. Decant supernatant.
5. Slurry the resin with sufficient solvent to fill reservoir column. Pour swiftly into reservoir. The column must be pre-filled with the same solvent and the reservoir column should be partly filled with solvent before slurry is poured. The use of larger slurry volumes may also provide good results; however, this will require (a) larger reservoir or (b) multiple reservoir fillings during the packing procedure.
6. Close reservoir with the Teflon plug beneath the column (see FIG. 1 of U.S. Pat. No. 4,131,547, plug No. 3); connect to pump; and immediately start pumping solvent through system at maximum flow rate if Ace Cat. No. 13265-25 Pump or similar solvent-delivery system is used (ca. 20 ml/minute).
7. Continue until column is completely filled with adsorbent. Pressure should not exceed maximum tolerance of column during this operation (ca. 200 psi for large columns and 300 psi for analytical columns). In most cases, pressures less than 200 psi will be sufficient.
8. Should pressure exceed maximum values, reduce flow-rate; pressure will drop.
9. After column has been filled with adsorbent, turn off pump; let pressure drop to zero; disconnect reservoir; replace reservoir with a pre-column; fill pre-column with solvent and small amount of adsorbent; and pump at maximum pressure until column is completely packed. For additional information, see general procedure. Always allow pressure to decrease slowly after turning off pump--this will prevent formation of any cracks or channels in the packing material.
10. Relieve pressure and disconnect precolumn carefully. With small spatula remove a few mm (2-4) of packing from top of column; place 1 or 2 filter(s) in top of column; gently depress to top of packing material, and place Teflon plug on top of column until seal is confirmed. Connect column to pump, put pressure on (usually less than 200 psi) and observe through glass wall on top of column if resin is packing any further. If packing material should continue to settle (this may be the case with larger columns), some dead space or channelling will appear and step 9 should be repeated.
EXAMPLE 15
Preparation of Tetrahydro-A-30912A
A-30912 factor A is dissolved in ethanol. PtO 2 in absolute ethanol is reduced to form Pt, which in turn is used to reduce the A-30912 factor A catalytically, using hydrogenation under positive pressure until the reaction is complete (about 2-3 hours). The reaction mixture is filtered and concentrated under vacuum. The residue is dissolved in a small amount of tert-butanol and lyophilized to give tetrahydro-A-30912A.
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Compounds of the formula ##STR1## wherein R 1 is a group of the formula: ##STR2## wherein A is divalent oxygen, sulfur, sulfinyl, or sulfonyl; A 1 is divalent oxygen, sulfur, sulfinyl, sulfonyl or --NH--; X is hydrogen, chloro, bromo, iodo, nitro, C 1 --C 3 alkyl, hydroxy, C 1 -C 3 alkoxy, mercapto, C 1 -C 3 alkylthio, carbamyl or C 1 -C 3 alkylcarbamyl; X 1 is chloro, bromo or iodo; R 2 is hydrogen, C 1 -C 18 alkyl or C 2 -C 18 alkenyl; W is C 1 -C 10 alkylene or C 2 -C 10 alkenylene; m, n and p are 0 or 1, but if m=0, n must=0; provided: that the sum of the carbon atoms in the R 2 and W groups must be greater than 4 but cannot exceed 21; that when X is mercapto. A and A 1 cannot be sulfinyl or sulfonyl; and that when A and A 1 are sulfinyl or sulfonyl, they must be in equal oxidation states.
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CROSS REFERENCES TO RELATED APPLICATIONS
A. A fixture adapted to hold an integrated circuit chip mounted on a flexible beam lead is described and claimed in application Ser. No. 671,238 filed March 29, 1976, entitled Fixture for an Integrated Circuit Chip which issued as U.S. Pat. No. 4,007,479 on Feb. 8, 1977. This patent is assigned to the same assignee as the present invention. The fixture disclosed and claim in the above identified patent is of the type that can be transferred by the transfer mechanism of this invention.
B. A magazine adapted to hold a stack of integrated circuit chips mounted in fixtures such as are disclosed in the application identified in paragraph A. above and from which the fixtures can be removed by the transfer mechanism of this invention is described and claimed in an application Ser. No. 712,564 filed Aug. 9, 1976 entitled Magazine for a Plurality of Fixtures Holding Integrated Circuit Chips by K. Boyd Tippetts and assigned to the assignee of this invention.
C. A machine for assembling into a magazine of the type described and claimed in the application identified in paragraph B. above, a plurality of fixtures of the types described and claimed in the application identified in paragraph A. above, and using the transfer mechanism of this invention is described and claimed in an application Ser. No. 712,563 filed Aug. 9, 1976 entitled Sequencer by John L. Kowalski and K. Boyd Tippetts and assigned to the assignee of this application.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention is in the field of transfer mechanisms for removing objects from the bottom of a stack of such objects stored in a first magazine and for loading and stacking such objects serially in a second magazine using the linear motion of an extractor and cam surfaces that project into the second magazine to stack such objects in the second magazine.
2. Description of the Prior Art
The development of integrated circuit (IC) chips, particularly medium and large scale IC chips, has created a need for improved manufacturing processes which lend themselves to automating the mounting of IC chips and their lead frames on substrates as part of the process of manufacturing compact electronic circuit packages which are also known as micropackages. The mounting of such a chip and its lead frame in a fixture, for testing the chip and its lead frame and to facilitate the mounting of such chips on substrates is know. However, in automating the process of manufacturing micropackages and since most micropackages require IC chips of several different types, it is desirable to assemble in a single holder, or magazine, the necessary number of fixtures holding appropriate types of IC chips used in manufacturing a given micropackage.
To automate this manufacturing step requires a mechanism to transfer a fixture from one magazine, a transferor magazine, into a second magazine, a transferee magazine. To simplify the mechanism, to insure its reliability, and to minimize the risk of damage to an IC chip and its lead frame, each such fixture is removed from the bottom of the stack of such fixtures in a transferor magazine and is loaded into and become, at least until the next fixture is loaded into the transferee magazine, the bottommost fixture in the stack of such fixtures in the transferee magazine.
The closest known relevant prior art is that which has been developed with respect to holders or magazines for film slides or transparencies; i.e., fixtures for holding segments of developed photographic film for use with a projector to project an enlarged image on a screen, for example. However, none of the prior art transfer mechanisms are capable of withdrawing the bottommost fixture of a first stack of such fixtures from a transferor magazine and bottom loading each such fixture into a stack of such fixtures in a transferee magazine.
SUMMARY OF THE INVENTION
The present invention provides a transfer mechanism for removing the bottommost object from a stack of like objects stored in a transferor magazine and inserting that object into a transferee magazine in which the object is inserted at the bottom of the stack of such objects. The mechanism requires only linear motion of an extractor to accomplish the transfer and stacking of an object. More particularly the transfer mechanism transfers, from one magazine to another, fixtures which are substantially identical in size and shape and which fixtures are adapted to hold an integrated circuit chip mounted on a flexible lead frame within a centrally located opening of the fixture. The parts of the transfer mechanism which contact a fixture during a transfer do not contact any part of the fixture in close proximity to the centrally located opening within which an IC chip is mounted to minimize the risk of damage to the chip during such a transfer.
The transfer mechanism of this invention has a support member or plate on which two bases are mounted. Magazines that are substantially identical in size and shape can be removably mounted on the bases. Each magazine is provided with an opening in one of its walls through which the objects or fixtures to be transferred can be inserted or removed by the transfer mechanism. The bases on which the magazines are mounted are positioned by positioning means with respect to each other so that corresponding openings of the magazine through which fixtures can be inserted or removed can be arranged to be opposite one another and substantially co-planar. The magazines are spaced apart a distance which is substantially less than the length of the object or fixture to be transferred, preferably a distance not greater than one half of said length. Transfer of a fixture is accomplished by an extractor which is operatively connected to a linear actuator. Thus, when the two bases are properly positioned with respect to each other, the extractor and the mechanism on which the extractor is mounted is free to move under the transferor magazine to the rear thereof to engage the bottommost fixture, to remove this fixture and to insert it into the transferee magazine. The second, or transferee, base is provided with a cam, the surfaces of which are contacted by the leading edge of the fixture as it is inserted into the transferee magazine. As a result, the fixture being inserted forces any fixtures then stacked in the transferee magazine to move upward. The position and shape of the cam surfaces are such that the stack of fixtures transferred into the second magazine will pivot about the higest points of the cam surfaces to uncover the opening in which a fixture is inserted by the transfer mechanism. As a result, a simple mechanism is provided which can unload from one magazine a fixture from the bottom of a stack of such fixtures and insert that fixture at the bottom of a stack of such fixtures in a second magazine.
The transfer mechanism is reliable and is designed to minimize the risk of damage to the IC chip which each fixture is adapted to have mounted on it. To assure this, the surfaces of the cam and the extractor which contact a fixture are split, or are divided, so that such surfaces do not come in contact with an IC chip mounted on a fixture being transferred.
The simplicity of the mechanism reduces the cost to produce, to operate, and to maintain the mechanism while permitting the automation of the transfer of fixtures holding IC chips from one magazine to another.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objects, features and advantages of the invention will be readily apparent from the following description of the preferred embodiment taken in conjunction with the accompanying drawings, although variations and modifications may be effected without departing from the spirit and scope of the novel concepts of the disclosure, and in which:
FIG. 1 is a fragmentary side elevation partly in section of the invention.
FIG. 2 is a section taken on line 2--2 of FIG. 1.
FIG. 3 is a fragmentary section taken on line 3--3 of FIG. 2.
FIG. 4 is a section taken on line 4--4 of FIG. 2.
FIG. 5 is a section taken on line 5--5 of FIG. 2.
FIG. 6 is an isometric view of a fixture.
FIG. 7 is an isometric view substantially illustrating the relationships between the extractor and cam of the invention when the extractor is in its extended position.
FIG. 8 is an isometric view substantially illustrating the relationship between the extractor and cam of the invention when the extractor is in its retracted position.
DESCRIPTION OF THE PREFERRED EMBODIMENT
In FIG. 1, transfer mechanism 10 has a support plate, or support member 11, the top surface 12 of which defines a reference plane which is substantially horizontal and on which transferor base 13 is mounted. Transferee base 14 is mounted on positioning means 14a. Magazine 15 is removably mounted on base 13 by mounting means generally designated by reference number 16. Referring to FIG. 4, it can be seen that base 13 is provided with a pair of integral vertical side walls 17, 18 the inner sides of which define two of the walls of a space having a substantially rectangulr cross section. Mounting means 16 comprises a pair of holders 19, 20 which are fixedly attached to the top surfaces of walls 17, 18 respectively. Holder 19, as is best seen in FIG. 1, is provided with a catch 21 within which the front ledge 22 of rail 23 of magazine 15 fits. The back ledge 24 of rail 23 is engaged by latch 25. Latch 25 is mounted for rotation about pivot 26, and is urged in a direction to positively engage ledge 24 by spring plunger 26a to substantially rigidly mount magazine 15 on base 13. A key 27 is mounted in the catch 27a of holder 20 to cooperate with key slot in rail 28 to make it difficult, if not impossible to improperly place and securely fasten magazine 15 on mounting means 16. The shape and dimensions of base 13 and of mounting means 16 are such that magazine 15 and particularly the plane determined by the upper surfaces of the rails 23, 28 is substantially parallel to the planar surface 12 of plate 11.
Magazine 15 has four walls, a front wall 29, a back wall 30, a side wall 31 and a second side wall 32. A front opening 33 is formed at the bottom of front wall 29 of magazine 15, with the bottom surface of wall 29 defining the top surface of opening 33. The inner surfaces of walls 29, 30, 31, 32 define a rectangular parallelapiped in which a plurality of fixtures 34 can be readily stacked. The height of front opening 33 measured from the top surfaces of the rails 23, 28 to the bottom surface of wall 29 is such that one and only one fixture 34 can be inserted or removed through front opening 33.
In FIG. 6 a typical 34, which the transfer mechanism 10 is adapted to transfer from transferor magazine 15 to transferee magazine 35, is illustrated. Embodiments of fixture 34 are described in greater detail in the patent identified in paragraph A of the section of this application entitled Cross References to Related Applications. The outer surfaces of fixture 34 substantially define a rectangular parallelapiped. An opening, or aperture, 36 is formed in fixture 34 substantially in the center of upper surface 37. Fixture 34 is adapted to have an integrated circuit chip and its flexible lead frame positioned in fixture 34 so that the IC chip is located within aperture, or opening, 36 with the chip between the top and bottom surfaces 37, 38 of fixture 34. The distance between the top and bottom surfaces 37, 38 of fixture 34 is the height of fixture 34. In a preferred embodiment, top and bottom surfaces 37, 38 are substantially square except for one corner which may be removed to provide a key, or indicia, of orientation 39.
Base 14 is fixedly secured to positioning means 14a which is mounted on frame 11. As is illustrated in FIGS. 2 and 5, the width of base 14 is greater than the width of base 13 so that a conventional ball slide 40 can be positioned in the opening formed in base 14. Because only the moveable element 41 of ball slide 40 projects or moves into the opening in base 13, the opening in base 13 is made smaller in both width and depth than the opening in base 14. A spacer 42 is mounted on base 14 and defines the top surface of the space within which the ball slide 40 is located. In the embodiment illustrated, mounting means 43 of base 14 is made integral with spacer 42. Fixed catch 44 and latch 45 of mounting means 43 are the functional equivalents of corresponding components of mounting means 16; i.e., to removably mount magazine 35 on base 14.
The dimensions of base 14, spacer 42 and mounting means 43 are such that the plane determined by the top surfaces of rails 46, 47, of magazine 35 when mounted on base 14 are substantially parallel with the top surface 12 of pklate 11, and this plane is substantially co-planar with the plane determined by the top surfaces of rails 23, 28 of magazine 15 when magazine 15 is mounted on base 13 as is shown generally in FIG. 1. When base 13 and base 14 are positioned on plate 11 so that when magazine 15 is mounted on base 13 and magazine 35 is mounted on base 14, front wall 48 of magazine 35 is substantially opposite front wall 29 of magazine 15, and so that the front openings 33 and 49 of magazine 15, 35 are substantially opposite one another, thus the two magazines 15 and 35 are in position to transfer a fixture from one to the other. In this position side walls 32, 50 and 31, 51 of magazine 15, 35 are also substantially co-planar.
Cam 52, which is removably secured to spacer 42 in a preferred embodiment, has two can surface 53, 54 as is best illustrated in FIGS. 7 and 8. The surfaces 53, 54 are spaced apart, or divided, a distance which is preferably equal to or greater than the width of opening 36 in fixture 34, so that an IC chip held by a fixture 34 will not contact cam surfaces 53, 54 during a transfer operation, or to state it another way, cam surfaces 53, 54 can engage only the bottom surface 38 of a fixture 34 during a transfer operation. A slot 55 is formed in the front portion of cam 52 as can best be seen in FIG. 2 and FIG. 7 to permit cam 52 and extractor 56 to overlap slightly as is illustrated in FIGS. 2 and 8.
Extractor 56 is provided with a first pair of substantially horizontal planar surfaces 57, 58 a second pair of substantially vertical planar surfaces 59, 60 and a third pair of cam surfaces 61, 62 with the distance between each pair of surfaces being preferably equal to or greater than the width of opening 36 in a fixture 34 so that an IC chip mounted in a fixture 34 will not contact a surface of extractor 56 during a transfer operation. This reduces the risk of damage to the IC chip positioned within aperture 36 of a fixture 34. Extractor 56 is fixedly secured to one end of moveable element 41 of ball slide 40 and is moveable between a first extended position illustrated in dotted lines in FIG. 3 and a second retracted position illustrated in solid lines. In the first position, substantially vertical surfaces 59, 60 are positioned so that the lower most fixture 34 of a stack of such fixtures in magazine 15 will be free to move downwardly, until it is supported on the top surfaces of rails 23, 28. Thus, vertical surfaces 59, 60 can engage a vertical surface, or wall such as back wall 63 of the bottommost fixture 34. Shortly thereafter extractor 34 begins to move from its frist position to its second position. In the second position of extractor 56, vertical surfaces 59, 60 are sufficiently within the interior of magazine 35 so that a fixture 34, which has just been loaded into magazine 35, is free to pivot about the highest points 64, 65 of cam surfaces 53, 54 to clear front opening 49 so that the next fixture 34 can be loaded into magazine 35. The planar surfaces 57, 58 of extractor 56, which are substantially horizontal when extractor 56 is mounted on moveable element 41, are slightly below the plane determined by the top surfaces of rails 23, 28 of magazine 15 and of rails 46, 47 of magazine 35 when magazines 15, 35 are mounted on bases 13, 14. The extent that vertical surfaces 59, 60 project above the plane defined by the top surfaces of rails 23, 28 of magazine 15 and rails 46, 47 of magazine 35 must not exceed the height of a fixture 34. Cam surfaces 61, 62 of extractor 56 extend from the top of vertical surfaces 59, 60 to the forward wall 66 of extractor 56. The intersection of cam surfaces 61, 62 with forward wall 66 is slightly below surfaces 57, 58 so that front wall 66 will not contact a fixture 34 in magazine 15 when extractor 56 is cycled from its second, or retracted, position to its first, or extended, position. A pair of recesses 67, 68 are formed in extractor 56 so that surfaces 57, 58 of extractor 56 and a part of the cam surfaces 53, 54 of cam 52 overlap when extractor 56 is in its second, or retracted, position.
Linear actuator 69 is mounted on positioning means 14a and is operatively connected by conventional connecting means 70 to moveable element 41 of ball slide 40 to cause extractor 56 to move between its two positions illustrated in FIG. 3. Actuator 69 can be of any conventional type powered by any suitable type of power which is readily available such as compressed air, hydraulic fluid, or electricity. In a preferred embodiment a pneumatic double acting cylinder is used.
In operation, a plurality of fixtures 34 are stacked vertically in magazine 15 with the bottommost one having part of its bottom surface 38 engaging the top surfaces of the rails 23, 28. The widths of the front openings 33 in magazine 15 and opening 49 in magazine 35 are slightly greater than the width of a fixture 34. The heights of the openings 33, 49 are such that only one fixture 34 can be removed through front opening 33 at any one time and only one fixture 34 can be inserted into front opening 49 at any one time.
A back opening 71 is formed in the back wall 30 of magazine 15 so that the highest surface of extractor 56 will not contact back wall 30 when extractor 56 is in its first position, i.e., when it has been moved underneath magazine 15 through the opening in base 13 and vertical surfaces 59, 60 are beyond the space within magazine 15 in which fixtures 34 are stacked. When actuator 69 is energized to cause extractor 56 to move from its second position to its first, cam surfaces 61, 62 displace upwardly the bottommost fixture 34 in the stack. Once extractor 56 is in its first position, the stack of fixtures 34 drops so that the bottommost fixture is supported on the top surfaces of rails 23, 28. When actuator 69 is energized, to cause through its operative connection with moveable element 41 the movement of extractor 56 from its first position to its second, vertical surfaces 59, 60 of fixture 56 engage the back wall of fixture 34 and moves the bottommost fixture 34 in the stack in magazine 15 through front opening 33. The top surfaces of the fixed catches of mounting means 43, such as catch 44, are below the plane defined by the top surfaces of rails 23, 28, 46 47 so that a fixture 34 will not contact any part of mounting means 43 during the transfer. The upper front edges of the rails 46 and 47 of magazine 35 are also beveled so that if the lower front edge 72 of a fixture 34 should be slightly below the plane determined by the top surfaces of rails 46, 47; fixture 34 will nevertheless be guided into magazine 35. The material from which each fixture 34 is made is relatively rigid, so that a fixture being transferred remains essentially horizontal during the transfer until its leading edge 72 has entered front opening 49 of magazine 35 because the distance between opening 33 and 49 is preferably not more than half the length of a fixture 34.
Substantially horizontal surfaces 57, 58 of extractor 56 support the bottom surface 38 of a fixture 34 during a transfer operation once the fixture is no longer supported by the top surfaces of rails 23, 28. The leading edge 72 will contact cam surfaces 53, 54 of cam 52 to wedge upwardly all fixtures 34 then stacked in magazine 35. Once a fixture 34 is loaded in magazine 35, it is no longer constrained from pivoting about the highest points 64, 65 of surfaces 53, 54 by the bottom surface of front wall 48, for example. When all constraints against such motion are removed, the weight of the fixture 34 being transferred and those in the stack above it, if any, cause the fixture 34 just transferred to tilt, or pivot, about the highest points 64, 65 of surfaces 53, 54 to clear, or unblock front opening 49 of transferee magazine 35.
When a second fixture 34 is to be transferred from magazine 15 to magazine 35, the extractor 56 is moved from its second position to its first by energizing actuator 69. As this occurs, cam surfaces 61, 62 of extractor 56 engage the bottom surface 38 of the bottommost fixture 34 stacked in magazine 15 and force that fixture and all those above it upwardly. Once extractor 56 has moved to its first position, cam surfaces 61, 62 no longer will contact the bottommost fixture 34, which is then free to move downwardly into engagement with the top surfaces of rails 23, 28. The transfer of a second fixture from magazine 15 to 35 is the result of energizing actuator 69, to move extractor 56 toward magazine 35 until it reaches its second position.
Each complete cycle of extractor 56 from its second position to the first position and then back to its second position when magazines 15 and 35 are properly positioned and a fixture is stored in magazine 15 will transfer a fixture 34 from a transferor magazine 15 into a transferee magazine 35. The maximum force required to stack up to 100 to 200 fixtures 34 in magazine 35 is relatively small and can be easily provided by a pneumatically powered linear actuator such as is used in a preferred embodiment. The magnitude of the forces applied to a fixture 34 during a transfer operation is insufficient to cause damage to IC chips and their lead frames which such fixtures are adapted to hold.
Transfer mechanism 10 has the advantages that extractor 56 can be moved in a straight line to remove the bottommost fixture 34 of a stack of such fixtures stored or held in magazine 15 and to insert the removed fixture into the bottom of a stack of such fixtures in magazine 35. The linear motion of extractor 56 not only transfers a fixture, but the interaction between the fixture being transferred and cam 52 causes each fixture so transferred to be vertically stacked in magazine 35. As a result, applicant's transfer mechanism is very reliable, is economical to manufacture and maintain, and accomplishes its function with substantially no risk of damage to a fixture and the device mounted on said fixture during such a transfer operation.
It should be evident that various modifications can be made in the described embodiment without departing from the scope of the present invention.
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A transfer mechanism for withdrawing an object from the bottom of a stack of such objects in a first magazine and for inserting said object at the bottom of a stack of such objects in a second magazine. The magazines are removably mounted on bases positioned with respect to each other so that the openings in the magazines through which an object is removed from one and inserted into the other are essentially opposite one another and are spaced apart less than the corresponding dimension of an object. An extractor removes the bottommost fixture from the first magazine and inserts that object into the second magazine. Cam surfaces which project into the second magazine cause the stack of such objects therein to clear the opening in the second magazine and cause the object being loaded to move the stack of such objects upwardly with the most recently inserted object at the bottom of the stack.
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CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation of U.S. patent application Ser. No. 10/448,695 filed May 30, 2003, which claims the priority of U.S. Provisional Application No. 60/384,697 filed May 31, 2002.
FIELD OF THE INVENTION
[0002] This invention relates generally to firearms, and more particularly to safety devices used in conjunction with firearms.
SUMMARY OF THE INVENTION
[0003] Firearm safety devices are disclosed.
[0004] In one aspect, the present invention relates to methods for disabling firearms. In one embodiment, the method comprises the steps of providing a firearm comprising a firing chamber, an opening in communication with the firing chamber and a bolt, providing a safety device comprising a chamber-disabling component constructed of a flexible material, the chamber-disabling component adapted to be inserted through the opening into the firing chamber with partial retraction of the bolt and inserting the safety device into the chamber of the firearm.
[0005] In another aspect, the present invention relates to safety devices. In one embodiment, the safety device comprises a chamber-disabling component constructed of a flexible material. The chamber-disabling component is adapted to be inserted through an opening defined in the firearm and is in communication with a firing chamber of the firearm with partial retraction of a bolt of the firearm.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] In the drawings, like reference characters generally refer to the same parts throughout the different views. Also, the drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the invention.
[0007] FIG. 1 is a perspective view of a firearm with a safety device of the present invention in place.
[0008] FIG. 2A is an enlarged view of a portion of the firearm of FIG. 1 with a safety device of the present invention in place. The firearm's ammunition is shown in phantom line.
[0009] FIG. 2B is an enlarged view of the firing chamber of FIG. 2A . A portion of the bolt of the firearm is shown in phantom line.
[0010] FIG. 2C is an enlarged view of the internal mechanism of a firearm with the safety device of the present invention in place.
[0011] FIG. 3 is an enlarged view of a portion of the firearm with a safety device of the present invention being removed from the chamber of the firearm.
[0012] FIG. 4 is a perspective view of a broken apart illustrative embodiment of the safety device of the present invention.
[0013] FIG. 5 is a perspective view of an attachment member secured to the safety device of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0014] Safety devices, according to the present invention, are useful to disable firearms that include a firing chamber, an opening in communication with the firing chamber and a bolt. These safety devices are adapted to be positioned in the firing chamber of the firearm by the user and adapted to be removed therefrom. Since the size of the firing chamber often varies from firearm to firearm, the safety device is preferably flexible enough to accommodate structural differences, while at the same time, sufficiently strong enough to withstand the pressure exerted by bolts inside the firing chamber.
[0015] Referring now to FIGS. 1 and 2 A, an illustrative embodiment of a safety device 10 of the present invention is positioned within the firing chamber 12 of an automatic/semi-automatic firearm 14 . The safety device 10 includes a body 16 , a grasping member 18 , and an attachment member 19 . Referring to FIGS. 2A and 2C , the firearm 14 includes a bolt 20 , a magazine 22 containing ammunition 24 , a bolt-retracting member 26 for actuating a bolt 20 to feed a round of ammunition from the magazine 22 and load the round into the firing chamber 12 , an ejection port 21 , a handguard 27 and a muzzle 28 .
[0016] Needless to say, before inserting the safety device 10 into the firearm 14 , the firing chamber 12 should not contain ammunition 24 . To insert the safety device 10 into the firearm 14 , the user may pull back the bolt-retracting member 26 a slight amount, and then insert the body 16 through the ejection port 21 into the firing chamber 12 . If the firearm 14 contains a magazine 22 with live ammunition 24 , the user need not completely retract the bolt-retracting member 26 before placement of the safety device 10 , because such action could load a round of live ammunition 24 . Provided, however, the safety device 10 is in place, full retraction of the bolt-retracting member 26 will not chamber a round of ammunition 24 because the safety device 10 blocks the firing chamber 12 . That is, the body 16 of the safety device 10 occupies space within the firing chamber 12 , and prevents ammunition 24 from being able to properly position itself therein. Moreover, pulling out the safety device 10 does not allow bolt 20 to retract beyond the magazine 22 to permit a round to be fed into the firing chamber 12 .
[0017] As shown in FIG. 2B , the body 16 is positioned within the firing chamber 12 of the firearm 14 , and, in one embodiment, may be abutted by the bolt 20 . In this embodiment, bolt 20 helps maintain the position of the body 16 in the firing chamber 12 of the firearm 14 by exerting pressure on the safety device 10 against the sidewall that defines the beginning of the firing chamber 12 . It is not necessary, however, that bolt 20 abut the body 16 . In non-spring activated firearms, for example, the body 16 may be dimensioned to maintain its position within the firing chamber 12 without assistance from the bolt 20 . For example, body 16 may be dimensioned so as to create an interference fit with either a dimension of the ejection port and/or an inner circumference of the firing chamber 12 . In addition, the attachment member 19 , which may be wrapped around the central action of the firearm 14 , may help ensure that the safety device 10 does not inadvertently fall out of position.
[0018] Once the safety device 10 is in position, it is plainly visible to the user and others. The grasping member 18 may enhance visibility. In some embodiments, the grasping member 18 may extend out of the firing chamber 12 , allowing the user to observe the safety device 10 from a distance, and easily remove it to prepare the firearm 14 for action. The grasping member 18 , as shown in FIGS. 1-3 , is in the form of a coil integral with the body 16 . The grasping member 18 need not, however, be integral with the body 16 . In fact, the grasping member 18 may take any form that allows the user to sufficiently grasp the safety device 10 for removal. The grasping member 18 may, for example, take the form of a T-shaped handle, a ring or virtually any other structure connected to the body 16 that the user can grasp. Under any of these constructions, the grasping member 18 may assist the user in removing the safety device 10 from the firing chamber 12 .
[0019] The attachment member 19 may also enhance visibility. Like the grasping member 18 , the attachment member 19 may extend out of the firing chamber 12 so that users and others may see the safety device 10 from a distance. To further enhance visibility, the safety device 10 , the grasping member 18 or the attachment member 19 , (or portions of each), may be fluorescent in color.
[0020] FIG. 5 shows one attachment member 19 according to the present invention. As mentioned, the attachment member 19 may help to ensure that the safety device does not inadvertently fall out of position. In addition, the attachment member 19 allows the user to avoid losing or misplacing the safety device 10 after its removal from the firing chamber 12 . After removal, the safety device 10 remains connected to the attachment member 19 , which, in turn, remains secured to the firearm 14 .
[0021] The attachment member 19 may be made of any suitable material or structure adapted to secure the safety device 10 to the firearm 14 . Such structures include, for example, a flexible band for tying a knot (as shown in FIG. 5 ), an elastic band, a wire twist or a strap containing an adhesive, such as VELCRO®, available from Velcro USA, Inc. The attachment member 19 may be secured to the firearm 14 by securing it around the central action of the firearm, as shown in FIGS. 1-3 . Any one or combination of ways may be employed to secure the safety device 10 to the firearm 14 .
[0022] The attachment member 19 may be secured to the safety device 10 in any suitable manner, including but not limited to, melting, tying, pinning, gluing or shrink wrapping the two together. Alternatively, the attachment member 19 and the body 16 may be formed as a single unit through injection molding.
[0023] FIG. 3 depicts removal of the safety device 10 from the firing chamber 12 of the firearm 14 by a user. As those of skill in the art will appreciate, the user may remove the safety device 10 , and then prepare the firearm 14 for action in two fast and easy motions. To remove the safety device 10 , the user may take hold of the grasping member 18 —in this case a coil—and pull it in a direction away from the firearm 14 . The smooth surface of the safety device facilitates sliding of the safety feature. Since the user need not retract the bolt 20 to remove the safety device 10 , the time spent removing the safety device 10 is minimal.
[0024] Minimizing removal time is particularly advantageous to users who need to defend themselves against deadly force. As shown in FIG. 3 , use of the coiled grasping member 18 allows the user to remove the safety device with one finger. Such construction allows an injured or incapacitated user to remove the safety device with minimal effort, when confronted with the use of deadly force. Moreover, with the safety device 10 herein sliding out of the firing chamber 12 , the bolt 20 is not moved back far enough to allow a round to enter the firing chamber 12 from the magazine 22 , and cause any premature loading or jamming of the weapon. Regardless of whether the safety device 10 is secured in the firearm 14 by the action of the bolt 20 pressing against the safety device 10 or by some other method, such as an interference fit between the device 10 and a dimension of the firing chamber 12 , a round of ammunition will not be placed in the firing chamber 12 by extraction of the safety device 10 from the firearm 14 . The user prepares the firearm 14 for action by pulling back and releasing the bolt-activating member 26 , thereby chambering a round of ammunition 24 .
[0025] FIG. 4 is a perspective view of one embodiment of a safety device 10 according to the present invention. The safety device 10 includes a body 16 , a first end 32 and a second end 34 . The body 16 may be elongated.
[0026] The safety device 10 may be solid or hollow. In FIG. 4 , the safety device 10 is hollow with a central lumen 36 running throughout.
[0027] Either one of the first or second ends 32 and 34 of the safety device 10 may be inserted into the firing chamber 12 of the firearm 14 . As shown in FIG. 2C , in one embodiment, the first or second end 32 and 34 , which is not inserted into the firing chamber 12 is positionable in an angular relationship to a longitudinal axis A of the firing chamber 12 . Alternatively, the first or second end 32 and 34 inserted into the firing chamber 12 is positionable in an angular relationship to a longitudinal axis B of the first or second end 32 and 34 not inserted into the firing chamber 12 . The angular relationship, in either case, may be transverse.
[0028] In other embodiments, the first or second end 32 and 34 not inserted into the firing chamber 12 may extend/hang out of the firing chamber 12 , allowing the user to grip the safety device 10 to remove it from the firing chamber 12 . As shown in FIGS. 1-3 , the first or second end 32 and 34 not inserted into the firing chamber 12 may also be wound about itself to form a coiled grasping member 18 .
[0029] Referring to FIG. 4 , in one embodiment of the invention, designed for operation with an M-16 or AR-15 rifle, the diameter d of the safety device 10 is between about 0.25 in. and 0.75 in., with 0.33 in preferred, and its length l is between about 3 in. and 6 in. Diameter d and length l may, however, vary broadly, depending on firearm dimensions and the needs of the user. In some embodiments, the dimensions of the safety device 10 are sufficient to prevent dirt and other debris from entering the firing chamber 12 after insertion of the safety device 10 into the firearm 14 . When the safety device 10 is so dimensioned, the need for mounting a dust cover over the ejection port may be eliminated.
[0030] The safety device 10 may generally be constructed of flexible materials. It is understood that materials for the safety device 10 of the present invention may also resist abrasion and cutting when the bolt exerts a force against the body 16 of the safety device 10 . In addition, these materials may resist elongation when the user removes the safety device 10 from the firing chamber 12 with the bolt exerting force against the body 16 of the safety device 10 . Resistance to cutting and abrasion also maintains the structural integrity of the body 16 , particularly when the bolt 20 of the firearm 14 contains lugs (not shown), which appear on the forward portion of the bolt 20 . Another aspect of the material used for the body 16 of the safety device 10 may include resistance to generation of particulates due to cutting or abrasion. Flakes or particles of material from which body 16 is formed may lodge in the internal mechanism of the firearm 14 , causing jamming, or fouling of the mechanism. Additionally or alternatively, such materials may include other beneficial qualities, such as resistance to temperature changes.
[0031] Examples of materials suitable for use with the safety device 10 of the present invention include, but are not limited to silicone, TEFLON®, polymeric compounds, polyurethane polymers, thermal plastics or malleable metals. The material of the safety device 10 may also comprise a smooth exterior surface.
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Methods for disabling firearms and firearm safety devices designed to reduce the risk of accidental discharge are provided. Safety devices according to the present invention comprise a chamber-disabling component constructed of a flexible material. The chamber-disabling component is adapted to be inserted through an opening in the firearm into the firing chamber with partial retraction of the bolt.
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CROSS REFERENCE TO RELATED APPLICATIONS
This is a divisional of application Ser. No. 09/799,210, filed Mar. 5, 2001, which is hereby incorporated by reference herein.
BACKGROUND OF INVENTION
1. Field of the Invention
The present invention is broadly concerned with novel substantially biodegradable and substantially water soluble anionic polymers and derivatives thereof which have significant utility in agricultural applications, especially plant nutrition and related areas. More particularly, the invention is concerned with such polymers, as well as methods of synthesis and use thereof, wherein the preferred polymers have significant levels of anionic groups. The most preferred polymers of the invention include recurring polymeric subunits made up of dicarboxylic (e.g., maleic acid or anhydride, itaconic acid or anhydride, and other derivatives thereof) monomers. The polymers may be applied directly to the ground adjacent growing plants, complexed onto ions, applied directly to seeds, and/or mixed with or coated with phosphate-based fertilizers to provide improved plant nutrition products.
2. Description of the Prior Art
Lignosulfonates, polyacrylates, polyaspartates and related compounds have become known to the art of agriculture as materials that facilitate nutrient absorption. All of them suffer from significant disadvantages, which decrease their utility in comparison to the art discussed herein and limit performance.
Lignosulfonates are a byproduct of paper pulping; they are derived from highly variable sources. They are subject to large, unpredictable variations in color, physical properties, and performance in application areas of interest for this invention.
Polyacrylates and polymers containing appreciable levels thereof can be prepared with good control over their composition and performance.
They are stable to pH variations. However, polyacrylates have just one carboxylate per repeat unit and they suffer from a very significant limitation in use, namely that they are not biodegradable. As a result, their utility for addressing the problems remedied by the instant invention is low.
Polyaspartates are biodegradable, but are very expensive, and are not stable outside a relatively small pH range of about 7 to about 10. They usually have very high color, and incorporate amide groups, which causes difficulties in formulating them. Additionally, polyaspartates have just one carboxylate per repeat unit and are therefore not a part of the present invention.
Preparation of itaconic acid homopolymers has been known to the art of polymer chemistry for an extended period of time. Several approaches to making it exist. One approach is by the direct polymerization of itaconic acid and/or its salts in aqueous or organic solutions under a wide range of conditions. Such reactions are described in the Journal of Organic Chemistry , Vol. 24, pg. 599 (1959) the teachings of which are incorporated by reference herein. Another approach is to begin with esters of itaconic acid, polymerize them under suitable conditions, and then hydrolyze the ester groups off in order to liberate polyitaconic acid. This approach is described in U.S. Pat. No. 3,055,873, the teachings of which are hereby incorporated by reference. Additionally, a very good summary of many aspects of the prior art is found in U.S. Pat. No. 5,223,592, the teachings of which are hereby incorporated by reference.
It will thus be seen that the prior art fails to disclose or provide polymers which can be synthesized using a variety of monomers and techniques in order to yield end products which are substantially biodegradable, substantially water soluble, and have wide applicability for agricultural uses. Moreover, no prior art or combination of prior art discloses preparation of itaconic acid copolymers with one or more organic acids containing at least one olefinic bond and at least two carboxylic acid groups. Furthermore, while the prior art does disclose a variety of methods for making polyitaconic acid homopolymer, it fails to teach, disclose, or suggest the utility such materials unexpectedly have for a wide variety of agricultural uses.
SUMMARY OF INVENTION
The present invention overcomes the problems outlined above and provides a new class of anionic polymers having a variety of uses, e.g., for enhancing takeup of nutrient by plants or for mixture with conventional phosphate-based fertilizers to provide an improved fertilizer product. Advantageously, the polymers are biodegradable, in that they degrade to environmentally innocuous compounds within a relatively short time (up to about 1 year) after being in intimate contact with soil. That is to say, the degradation products are compounds such as CO 2 and H 2 O or the degradation products are absorbed as food or nutrients by soil microorganisms and plants. Similarly, derivatives of the polymers and/or salts of the polymers (e.g. ammonium salt forms of the polymer) also degrade within a relatively short time, during which significant fractions of the weight of the polymer are believed to be metabolized by soil organisms.
Broadly speaking, the anionic polymers of the invention include recurring polymeric subunits made up of at least two different moieties individually and respectively taken from the group consisting of what have been denominated for ease of reference as B and C moieties; alternately, the polymers may be formed from recurring C moieties. Thus, exemplary polymeric subunits may be BC, CB, CC, or any other combination of B, and C moieties; moreover, in a given polymer different polymeric subunits may include different types of moieties, e.g., in an BC recurring polymeric unit polymer, the B moiety may be different in different units.
In detail, moiety B is of the general formula
wherein each R 7 is individually and respectively selected from the group consisting of H, OH, C 1 -C 30 straight, branched chain and cyclic alkyl or aryl groups, C 1 -C 30 straight, branched chain and cyclic alkyl or aryl formate (C 0 ), acetate (C 1 ), propionate (C 2 ), butyrate (C 3 ), etc. up to C 30 based ester groups, R′CO 2 groups, OR′ groups and COOX groups, wherein R′ is selected from the group consisting of C 1 -C 30 straight, branched chain and cyclic alkyl or aryl groups and X is selected from the group consisting of H, the alkali metals, NH 4 and the C 1 -C 4 alkyl ammonium groups, R 3 and R 4 are individually and respectively selected from the group consisting of H, C 1 -C 30 straight, branched chain and cyclic alkyl or aryl groups, R 5 , R 6 , R 10 and R 11 are individually and respectively selected from the group consisting of H, the alkali metals, NH 4 and the C 1 -C 4 alkyl ammonium groups, Y is selected from the group consisting of Fe, Mn, Mg, Zn, Cu, Ni, Co, Mo, V and Ca, and R 8 and R 9 are individually and respectively selected from the group consisting of nothing (i.e., the groups are non-existent), CH 2 , C 2 H 4 , and C 3 H 6 , each of said moieties having or being modified to have a total of two COO groups therein.
As can be appreciated, the polymers of the invention can have different sequences of recurring polymeric subunits as defined above (For example, a polymer comprising B and C subunits may include all three forms of B subunit and all three forms of C subunit. However, for reasons of cost and ease of synthesis, the most useful polymers include recurring polymeric subunits made up of B and C moieties. In the case of the polymer made up of B and C moieties, R 5 , R 6 , R 10 , and R 11 are individually and respectively selected from the group consisting of H, the alkali metals, NH 4 , and the C 1 -C 4 alkyl ammonium groups. This particular polymer is sometimes referred to as a butanedioic methylenesuccinic acid copolymer and can include various salts and derivatives thereof. The most preferred polymers of the invention are composed of recurring polymeric subunits formed of B and C moieties and have the generalized formula
Preferred forms of this polymer have R 5 , R 6 , R 10 , and R 11 individually and respectively selected from the group consisting of H, the alkali metals, NH 4 , and the C 1 -C 4 alkyl ammonium groups. Other preferred forms of this polymer are capable of having a wide range of repeat unit concentrations in the polymer. For example, polymers having varying ratios of B:C (e.g., 10:90, 60:40, 50:50 and even 0:100) are contemplated and embraced by the present invention. Such polymers would be produced by varying monomer amounts in the reaction mixture from which the final product is eventually produced and the B and C type repeating units may be arranged in the polymer backbone in random order or in an alternating pattern.
The polymers of the invention may have a wide variety of molecular weights, ranging for example from 500-5,000,000, depending chiefly upon the desired end use. Additionally, n can range from about 1-10,000 and more preferably from about 1-5,000.
For purposes of the present invention, it is preferred to use dicarboxylic acids, precursors and derivatives thereof for the practice of the invention. For example, terpolymers containing mono and dicarboxylic acids with vinyl esters and vinyl alcohol are contemplated, however, polymers incorporating dicarboxylic acids were unexpectedly found to be significantly more useful for the purposes of this invention. This finding was in contrast to the conventional teachings that mixtures of mono and dicarboxylates were superior in applications previously suggested for mono-carboxylate polymers. Thus, the use of dicarboxylic acid derived polymers for agricultural applications is unprecedented and produced unexpected results. It is understood that when dicarboxylic acids are mentioned herein, various precursors and derivatives of such are contemplated and well within the scope of the present invention. Put another way, copolymers of the present are made up of monomers bearing at least two carboxylic groups or precursors and/or derivatives thereof. The polymers of the invention may have a wide variety of molecular weights, ranging for example from 500-5,000,000, more preferably from about 1,500-20,000, depending chiefly upon the desired end use.
In many applications, and especially for agricultural uses, the polymers of the invention may be mixed with or complexed with a metal or non-metal ion, and especially ions selected from the group consisting of Fe, Mn, Mg, Zn, Cu, Ni, Co, Mo, V, Cr, Si, B, and Ca. Alternatively, polymers containing, mixed with or complexed with such elements may be formulated using a wide variety of methods that are well known in the art of fertilizer formulation. Examples of such alternative methods include, forming an aqueous solution containing molybdate and the sodium salt of polymers in accordance with the invention, forming an aqueous solution which contains a zinc complex of polymers in accordance with the present invention and sodium molybdate, and combinations of such methods. In these examples, the presence of the polymer in soil adjacent growing plants would be expected to enhance the availability of these elements to these growing plants. In the case of Si and B, the element would merely be mixed with the polymer rather than having a coordinate metal complex formation. However, in these cases, the availability of these ions would be increased for uptake by growing plants and will be termed “complexed” for purposes of this application.
The polymers hereof (with or without complexed ions) may be used directly as plant growth enhancers. For example, such polymers may be dispersed in a liquid aqueous medium and applied foliarly to plant leaves or applied to the earth adjacent growing plants. It has been found that the polymers increase the plant's uptake of both polymer-borne metal nutrients and ambient non-polymer nutrients found in adjacent soil. In such uses, plant growth-enhancing amounts of compositions comprising the above-defined polymers are employed, either in liquid dispersions or in dried, granular form. Thus, application of polymer alone results in improved plant growth characteristics, presumably by increasing the availability of naturally occurring ambient nutrients. Typically, the polymers are applied at a level of from about 0.001 to about 100 lbs. polymer per acre of growing plants, and more preferably from about 0.005 to about 50 lbs. polymer per acre, and still more preferably from about 0.01 to about 2 lbs.
In other preferred uses, the polymers may be used to form composite products where the polymers are in intimate contact with fertilizer products including but not limited to phosphate-based fertilizers such as monoammonium phosphate (MAP), diammonium phosphate (DAP), any one of a number of well known N—P—K fertilizer products, and/or fertilizers containing nitrogen materials such as ammonia (anhydrous or aqueous), ammonium nitrate, ammonium sulfate, urea, ammonium phosphates, sodium nitrate, calcium nitrate, potassium nitrate, nitrate of soda, urea formaldehyde, metal (e.g. zinc, iron) ammonium phosphates; phosphorous materials such as calcium phosphates (normal phosphate and super phosphate), ammonium phosphate, ammoniated super phosphate, phosphoric acid, superphosphoric acid, basic slag, rock phosphate, colloidal phosphate, bone phosphate; potassium materials such as potassium chloride, potassium sulfate, potassium nitrate, potassium phosphate, potassium hydroxide, potassium carbonate; calcium materials, such as calcium sulfate, calcium carbonate, calcium nitrate; magnesium materials, such as magnesium carbonate, magnesium oxide, magnesium sulfate, magnesium, hydroxide; sulfur materials such as ammonium sulfate, sulfates of other fertilizers discussed herein, ammonium thiosulfate, elemental sulfur (either alone or included with or coated on other fertilizers); micronutrients such as Zn, Mn, Cu, Fe, and other micronutrients discussed herein; oxides, sulfates, chlorides, and chelates of such micronutrients (e.g., zinc oxide, zinc sulfate and zinc chloride); such chelates sequestered onto other carriers such as EDTA; boron materials such as boric acid, sodium borate or calcium borate; and molybdenum materials such as sodium molybdate. As known in the art, these fertilizer products can exist as dry powders/granules or as water solutions.
In such contexts, the polymers may be co-ground with the fertilizer products, applied as a surface coating to the fertilizer products, or otherwise thoroughly mixed with the fertilizer products. Preferably, in such combined fertilizer/polymer compositions, the fertilizer is in the form of particles having an average diameter of from about powder size (less than about 0.001 cm) to about 10 cm, more preferably from about 0.1 cm to about 2 cm, and still more preferably from about 0.15 cm to about 0.3 cm. The polymer is present in such combined products at a level of from about 0.001 g to about 20 g polymer per 100 g phosphate-based fertilizer, more preferably from about 0.1 g to about 10 g polymer per 100 g phosphate-based fertilizer, and still more preferably from about 0.5 g to about 2 g polymer per 100 g phosphate-based fertilizer. Again, the polymeric fraction of such combined products may include the polymers defined above, or such polymers complexed with the aforementioned ions. In the case of the combined fertilizer/polymer products, the combined product is applied at a level so that the polymer fraction is applied at a level of from about 0.001 to about 20 lbs. polymer per acre of growing plants, more preferably from about 0.01 to about 10 lbs polymer per acre of growing plants, and still more preferably from about 0.5 to about 2 lbs polymer per acre of growing plants. The combined products can likewise be applied as liquid dispersions or as drygranulated products, at the discretion of the user. When polymers in accordance with the present invention are used as a coating, the polymer comprises between about 0.005% and about 15% by weight of the coated fertilizer product, more preferably the polymer comprises between about 0.01% and about 10% by weight of the coated fertilizer product, and most preferably between 0.5% and about 1% by weight of the coated fertilizer product. It has been found that polymer-coated fertilizer products obtain highly desirable characteristics due to the alteration of mechanical and physical properties of the fertilizer.
Additionally, use of polymers in accordance with the present invention increases the availability of phosphorus and other common fertilizer ingredients and decreases nitrogen volatilization, thereby rendering ambient levels of such plant nutrient available for uptake by growing plants. In such cases, the polymer can be applied as a coating to fertilizer products prior to their introduction into the soil. In turn, plants grown in soil containing such polymers exhibit enhanced growth characteristics.
Another alternative use of polymers in accordance with the present invention includes using the polymer as a seed coating. In such cases, the polymer comprises at least about 0.005% and about 15% by weight of the coated seed, more preferably, the polymer comprises between about 0.01% and about 10% by weight of the coated seed, and most preferably between 0.5% and about 1% by weight of the coated seed. Use of the polymer as a seed coating provides polymer in close proximity to the seed when planted so that the polymer can exert its beneficial effects in the environment where it is most needed. That is to say that the polymer provides an environment conducive to enhanced plant growth in the area where the effects can be localized around the desired plant. In the case of seeds, the polymer coating provides an enhanced opportunity for seed germination and subsequent plant growth due to the decrease in nitrogen volatilization an increase in plant nutrient availability which is provided by the polymer.
In general, the polymers of the invention are made by free radical polymerization serving to convert selected monomers into the desired polymers with recurring polymeric subunits. Such polymers may be further modified to impart particular structures and/or properties. A variety of techniques can be used for generating free radicals, such as addition of peroxides, hydroperoxides, azo initiators, persulfates, percarbonates, per-acid, charge transfer complexes, irradiation (e.g., UV, electron beam, X-ray, gamma-radiation and other ionizing radiation types), and combinations of these techniques. Of course, an extensive variety of methods and techniques are well known in the art of polymer chemistry for initiating free-radical polymerizations. Those enumerated herein are but some of the more frequently used methods and techniques. Any suitable technique for performing free-radical polymerization is likely to be useful for the purposes of practicing the present invention.
The polymerization reactions are carried out in a compatible solvent system, namely a system which does not unduly interfere with the desired polymerization, using essentially any desired monomer concentrations. A number of suitable aqueous or non-aqueous solvent systems can be employed, such as ketones, alcohols, esters, ethers, aromatic solvents, water and mixtures thereof. Water alone and the lower (C 1 -C 4 ) ketones and alcohols are especially preferred, and these may be mixed with water if desired. In some instances, the polymerization reactions are carried out with the substantial exclusion of oxygen, and most usually under an inert gas such as nitrogen or argon. There is no particular criticality in the type of equipment used in the synthesis of the polymers, i.e., stirred tank reactors, continuous stirred tank reactors, plug flow reactors, tube reactors and any combination of the foregoing arranged in series may be employed. A wide range of suitable reaction arrangements are well known to the art of polymerization.
In general, the initial polymerization step is carried out at a temperature of from about 0° C. to about 120° C. (more preferably from about 30° C. to about 95° C. for a period of from about 0.25 hours to about 24 hours and even more preferably from about 0.25 hours to about 5 hours). Usually, the reaction is carried out with continuous stirring.
Thereafter, the completed polymer may be recovered as a liquid dispersion or dried to a solid form. Additionally, in many cases it is preferred to react the polymer with an ion such as Fe, Mn, Mg, Zn, Cu, Ni, Co, Mo, V, Cr, and Ca to form a coordinate metal complex. Techniques for making metal-containing polymer compounds are well known to those skilled in the art. In some of these techniques, a metal's oxide, hydroxide, carbonate, salt, or other similar compound may be reacted with the polymer in acid form. These techniques also include reacting a finely divided free metal with a solution of an acid form of a polymer described or suggested herein. Additionally, the structures of complexes or salts of polymers with metals in general, and transition metals in particular, can be highly variable and difficult to precisely define. Thus, the depictions used herein are for illustrative purposes only and it is contemplated that desired metals or mixtures of such are bonded to the polymer backbone by chemical bonds. Alternatively, the metal may be bonded to other atoms in addition to those shown. For example, in the case of the structure shown herein for the second reactant, there may be additional atoms or functional groups bonded to the Y. These atoms include, but are not limited to, oxygen, sulfur, halogens, etc. and potential functional groups include (but are not limited to) sulfate, hydroxide, etc. It is understood by those skilled in the art of coordination compound chemistry that a broad range of may be formed depending upon the preparation protocol, the identity of the metal, the metal's oxidation state, the starting materials, etc. In the case of Si and B ions, the polymer is merely mixed with these ions and does not form a coordinate complex. However, the availability of these ions to growing plants is increased. It is also noted that it is possible to react the monomers used to form the polymer with ions in similar ways before polymerization. In other words, the monomers can be reacted with metals (including metals in their pure state, as oxides, carbonates, hydroxides, or other suitable metal-containing compounds) or ions in such a way as to result in the formation of a salt, a complex, or a similar molecule. It is also contemplated that reaction of monomers with a metal can be followed by their polymerization and subsequent reaction with a further portion of metal.
In more detail, the preferred method for polymer synthesis comprises the steps of providing a reaction mixture comprising at least two different reactants selected from the group consisting of first and second reactants. The first reactant is of the general formula
With reference to the above formulae, each R 7 is individually and respectively selected from the group consisting of H, OH, C 1 -C 30 straight, branched chain and cyclic alkyl or aryl groups, C 1 -C 30 straight, branched chain and cyclic alkyl or aryl formate (C 0 ), acetate (C 1 ), propionate (C 2 ), butyrate (C 3 ), etc. up to C 30 based ester groups, R′CO 2 groups, OR′ groups and COOX groups, wherein R′ is selected from the group consisting of C 1 -C 30 straight, branched chain and cyclic alkyl or aryl groups and X is selected from the group consisting of H, the alkali metals, NH 4 and the C 1 -C 4 alkyl ammonium groups, R 3 and R 4 are individually and respectively selected from the group consisting of H, C 1 -C 30 straight, branched chain and cyclic alkyl or aryl groups, R 5 , R 6 , R 10 and R 11 are individually and respectively selected from the group consisting of H, the alkali metals, NH 4 and the C 1 -C 4 alkyl ammonium groups, Y is selected from the group consisting of Fe, Mn, Mg, Zn, Cu, Ni, Co, Mo, V and Ca, and R 8 and R 9 are individually and respectively selected from the group consisting of nothing (i.e., the groups are non-existent), CH 2 , C 2 H 4 , and C 3 H 6 , each of said moieties having or being modified to have a total of two COO groups therein.
Selected monomers and reactants are dispersed in a suitable solvent system and placed in a reactor. The polymerization reaction is then carried out to obtain an initial polymerized product having the described recurring polymeric subunits. Put another way, the general reaction proceeds by dissolving monomers (e.g., maleic anhydride and itaconic acid) in acetone and/or water in either equimolar or non-equimolar amounts. A free radical initiator is then introduced and copolymerization takes place in solution. After the reaction is complete and a major fraction of the monomer has been reacted, the resulting solution for this particular example is a maleic acid-itaconic acid copolymer. Of course, if all monomers have not undergone polymerization, the resulting solution will contain a small portion of monomers which do not affect later use of the polymer.
Another important aspect of the present invention is the enhancement of dust control when a polymer in accordance with the present is applied as a coating to a fertilizer. It has been found that coating the fertilizer with a polymer in accordance with the present invention greatly decreases the generation of dust. Such a dust-controlling property of polymers in accordance with the present invention was entirely unexpected yet provides a distinct advance in the state of the art in that, typically, a separate dust-controlling substance is applied to fertilizers prior to their application in a field. Generally, the polymer will be applied as a coating to the surface of the fertilizer in order to form a substantially coated fertilizer product. As noted above, the polymer may comprise between about 0.005% to about 15% by weight of the coated fertilizer product, however, for dust control, it is preferred to have the coating level be up to about 0.5% w/w as it has been demonstrated that coating levels as low as 0.5% w/w completely inhibit the generation of dust. Of course, the coating level can be increased to levels greater than 0.5% w/w in order to enhance other beneficial properties of the polymer while still completely inhibiting dust generation. Thus, the present invention will eliminate the need for this separate dust-controlling substance while still contributing all of the beneficial properties described above.
Again, it is important to note that the aforementioned methods and procedures are merely preferred methods of practicing the present invention and those skilled in the art understand that a large number of variations and broadly analogous procedures can be carried out using the teachings contained herein. For example, polymers may be used as is (in the acid form) or further reacted with various materials to make salts and/or complexes. Furthermore, complexes or salts with various metals may be formed by reacting the acid form with various oxides, hydroxides, carbonates, and free metals under suitable conditions. Such reactions are well known in the art and include (but are not limited to) various techniques of reagent mixing, monomer and/or solvent feed, etc. One possible technique would be gradual or stepwise addition of an initiator to a reaction in progress. Other potential techniques include the addition of chain transfer agents, free radical initiator activators, molecular weight moderators/control agents, use of multiple initiators, initiator quenchers, inhibitors, etc. Of course, this list is not comprehensive but merely serves to demonstrate that there are a wide variety of techniques available to those skilled in the art and that all such techniques are embraced by the present invention.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a graph illustrating the percentage of nitrogen and ammonia lost from untreated urea over a sixteen day testing period; and
FIG. 2 is a graph illustrating the percentage of nitrogen and ammonia lost over a sixteen day testing period from urea coated with polymer.
DETAILED DESCRIPTION
The following examples set forth techniques for the synthesis of polymers in accordance with the invention, and various uses thereof. It is to be understood that these examples are provided by way of illustration only and nothing therein should be taken as a limitation upon the overall scope of the invention.
EXAMPLE 1
Acetone (803 g), maleic anhydride (140 g), itaconic acid (185 g) and benzoyl peroxide (11 g) were stirred together under inert gas in a reactor. The reactor provided included a suitably sized cylindrical jacketed glass reactor with mechanical agitator, a contents temperature measurement device in contact with the contents of the reactor, an inert gas inlet, and a removable reflux condenser. This mixture was heated by circulating heated oil in the reactor jacket and stirred vigorously at an internal temperature of about 65-70° C. This reaction was carried out over a period of about 5 hours. At this point, the contents of the reaction vessel were poured into 300 g water with vigorous mixing. This gave a clear solution. The solution was subjected to distillation at reduced pressure to drive off excess solvent and water. After sufficient solvent and water have been removed, the solid product of the reaction precipitates from the concentrated solution, and is recovered. The solids are subsequently dried in vacuo. A schematic representation of this reaction is shown below.
EXAMPLE 2
This reaction was carried out in equipment similar to that used in Example 1 above. The following procedure was followed:847 g purified water was placed into the reactor. Next, 172 g itaconic acid and 130 g maleic anhydride were added with vigorous stirring. This mixture was heated to about 85-90° C., at which temperature this mixture exists as a clear solution. When the mixture reached the desired temperature, 15 g of potassium persulfate was added to the solution. The reaction mixture was allowed to stir for 3 hours, and a second portion of persulfate, equal to the first, was added, and allowed to react for a further 3 hours. Product was isolated in the same manner as described for Example 1. A schematic representation of this reaction is shown below
EXAMPLE 3
The procedure of Example 2 was followed, but the product was not isolated. Instead, it was diluted with water to give a 10% w/w solution. Then, 6.62 g ZnO was added to 200 g of this solution. The oxide dissolved in the liquid with stirring. This solution was then dried to a white highly water-soluble powder.
EXAMPLE 4
The procedure of Example 2 was followed, but the product was not isolated. Instead, it was diluted with water to give a 30% w/w solution. 6.66 g CuO was then added to 260 g of this solution. The oxide dissolved in the liquid with stirring and heating to about 60 degrees C. This solution was then dried to a green-colored highly water-soluble powder.
EXAMPLE 5
The procedure of Example 2 was followed, but the product was not isolated. Instead, it was diluted with water to give a 10% w/w solution. To 200 g of this solution, 5.76 g MnO 2 was added. The oxide dissolved in the liquid with stirring and heating to about 60 degrees C. This solution was then dried to a pink-colored, highly water-soluble powder.
EXAMPLE 6
The procedure of Example 2 was followed, but the product was not isolated. Instead, it was diluted with water to give a 10% w/w solution. Next, 3.28 g MgO was added to 200 g of this solution. The oxide dissolved in the liquid with stirring. This solution was then dried to a white highly water-soluble powder.
EXAMPLE 7
The procedure of Example 2 was followed, but the product was not isolated. Instead, it was diluted with water to give a 25% w/w solution. 2.96 g V 2 O 5 was then added to 240 g of this solution. The oxide dissolved in the liquid with stirring. This solution was then dried to a green highly water-soluble powder.
EXAMPLE 8
The procedure of Example 2 was followed, but the product was not isolated. Instead, it was diluted with water to give a 10% w/w solution. To 200 g of this solution, 3.03 g metallic Fe in finely powdered form was added. The metal dissolved in the liquid with stirring. This solution was then dried to a yellow highly water-soluble powder.
EXAMPLE 9
The procedure of Example 2 was followed, but the product was not isolated. Instead, it was diluted with water to give a 10% w/w solution. To 200 g of this solution, 8.14 g CaCO 3 was added. The carbonate dissolved in the liquid with stirring. This solution was then dried to a white highly water-soluble powder.
EXAMPLE 10
The procedure of Example 2 was followed, but the product was not isolated. Instead, it was neutralized to a pH of 7 with aqueous NaOH (40% w/w). The resulting solution was dried to give a white highly water-soluble powder.
EXAMPLE 11
The procedure of Example 2 was followed, but the product was not isolated. Instead, it was neutralized to a pH of 7 with aqueous KOH (30% w/w). The resulting solution was dried to give a white highly water-soluble powder.
EXAMPLE 12
The procedure of Example 2 was followed, but the product was not isolated. Instead, it was neutralized to a pH of 3 with anhydrous ammonia gas that was introduced into the solution by means of a gas dispersion tube. The resulting solution was dried to give a white highly water-soluble powder.
EXAMPLE 13
This example followed the procedure of Example 12. However, the anhydrous ammonia gas was introduced into the solution prior to the addition of the initiator. Again, the solution was neutralized to a pH of 3. Thus, the neutralization step partially neutralized the monomers rather than the polymer. The initiator used for this example was ammonium persulfate and the reaction scheme is depicted below.
In this scheme, the first three steps are just an extensive elaboration of the neutralization of the water-monomer mixture with anhydrous ammonia to a pH of 3. Such a reaction is equally describable by depicting a reaction scheme using starting materials including itaconic acid, maleic anhydride, anhydrous ammonia, and water which results in the product shown at the far right end in step 3. The salts as drawn are theoretical, however, this does show that the monomers are not completely neutralized nor are they completely un-neutralized. Of course, it is well within the scope of the present invention to have the monomers completely neutralized or completely un-neutralized by the addition of any suitable base as well as having a wide range of B:C monomer ratios.
EXAMPLE 14
This reaction was carried out in equipment similar to that used in Example 1 above. The following procedure was followed:1990 g purified water was placed into the reactor and 1260 g itaconic acid and 950 g maleic anhydride was added with vigorous stirring. This mixture was then heated to about 75 C, at which temperature this mixture as a clear solution. When the mixture reached the desired temperature, 270 g potassium persulfate was added stepwise to the solution. Persulfate addition was conducted at 1 hour intervals in amount of 30 g per addition. Product was isolated in the same manner as described in Example 1.
EXAMPLE 15
This reaction was carried out in the same fashion as Example 14, but ammonium persulfate was used. The total amount of persulfate was 225 g.
EXAMPLE 16
In this example, the effect of polymer upon volatilization of ammonia from urea was determined. A 100 g sample of granular urea was coated with the H polymer by adding 1% polymer and 3.5 ml liquid (H 2 O) to the urea and shaking the mixture to achieve a uniform coating on the urea. Clay (kaolanite clay) was then added to absorb the excess H 2 O. Polymer coated urea and uncoated urea were placed in chambers that were optimized for the volatilization of ammonia. The polymer coated urea and uncoated urea were then analyzed for content over a sixteen day period.
FIG. 1 illustrates the amount of nitrogen and ammonia lost from the urea over the sixteen day testing period. This loss totaled 37.4%. In comparison, FIG. 2 illustrates the amount of ammonia and nitrogen lost from the urea coated with the polymer. The polymer coated urea experienced a 54% reduction of nitrogen and ammonia loss in comparison to the uncoated urea. Thus, the polymer coating greatly decreased nitrogen volatilization. Such a decrease in volatilization would also result from the polymer and urea being co-ground together or by having the polymer in close proximity to the urea in soil.
EXAMPLE 17
In this example the effects of liquid ammoniated phosphates and polymer-treated liquid ammoniated phosphates on acid soils having a high phosphorous fixation capacity period were compared. Untreated liquid ammoniated phosphate (10-34-0) and liquid ammoniated phosphate with 1% by weight polymer and liquid ammoniated phosphate with 2% by weight ammoniated polymer were applied in a band (2 inches below and 2 inches beneath) in the seed row. The polymer used for this experiment was the sodium form. Corn was grown to the six leaf stage and then harvested. The plants were dried, and the dry weight recorded. Results of this experiment are given in Table 1.
The acid soil was very responsive to the 10-34-0 controlled and corn grown in this soil experienced a 151% increase in dry weight. In comparison, the addition of 1% polymer increased corn growth by an additional 19% and addition of the 2% polymer increased corn growth by 26% in comparison to the 10-34-0 control. Thus, addition of the polymer had advantageous effects on the growth of corn
TABLE 1
Acid Soil
Dry Matter/grams
No P Control
1.67
10-34-0 Control (No Polymer)
4.20
10-34-0 1% Polymer
5.00
10-34-0 2% Polymer
5.30
EXAMPLE 18
In this example the efficiency of different salts of the anionic polymer as a coating on phosphate fertilizer was evaluated. Polymer coatings were applied on a 1% by weight basis onto MAP. The test crop for this experiment was corn and the polymer used was a polymer formed by B and C monomers. All phosphorous treatments were banded 2 inches below and 2 inches away from the seed rows. The acid in calcareous soils used in this experiment are both known to fix phosphorous fertilizer, thereby limiting the growth of crops. The corn was harvested at the six leaf stage and dry weights were determined as an indication as the efficiency of the coatings on phosphorous uptake and resultant corn growth. Results of this experiment are given below in Table 2. Table 2 shows that both the hydrogen and ammonium salts of the polymer were effective at increasing corn growth when combined with MAP. The acid control (untreated MAP) produced 294% more dry matter than the control which did not include MAP. These results illustrate that the soil is very responsive to phosphorous. When the MAP was coated with the anionic polymer charged neutralized with hydrogen, dry matter yields were increased by 41.9%. The calcareous control (untreated MAP) produced 128% more dry matter than the control which did not include any MAP. The MAP treated with the anionic polymer charge neutralized with ammonium, produced 15.9% more dry matter than the MAP control
TABLE 2
Acid Soil
Calcareous Soil
(Dry Matter/grams)
(Dry Matter/grams)
No P Control (no MAP)
4.72
12.4
MAP Control
18.6
28.3
1% Hydrogen Polymer
26.4
1% Ammonium Polymer
32.81
EXAMPLE 19
In this example, the effect of a zinc polymer on corn seedling growth was determined. A 21% zinc-polymer was prepared and applied to corn seeds at a rate of eight ounces per 100 pounds of seed. The seeds, were planted in six inch pots and allowed to grow until they reached the four leaf stage. The soil was calcareous and had low zinc availability. At the four leaf stage, plants were harvested and dried, then the dry weights were determined. Dry weights increased by 29% on the plants where the zinc-polymer was applied to the seed versus the control.
EXAMPLE 20
This example tested the dust controlling effects of the polymer on fertilizer particles. The test used was an abrasion resistance test based on the rotary drum method. This tests the resistance to dust and fines formation resulting from granule-granule and granule-equipment contact. It is useful in determining material losses; handling, storage, and application properties; and pollution control equipment requirements. A sample was first screened manually to separate out a fraction containing approximately minus 3.35 mm to 1.00 mm granules. A representative 100 cm 3 portion of the minus 3.35- plus 1.00-mm fraction was then used in the test. A 20 g portion of this was then weighed out and placed in a 100 ml rectangular polyethylene bottle together with 10 stainless steel balls measuring 7.9 mm in diameter and having a total weight of 20.0 g. The bottle was then closed and manually shaken for five minutes. In order to ensure uniform shaking for all samples in an analytical run, all sample bottles were taped together into one block. At the end of the run, the balls were removed manually, and the bottle contents examined. Fines were separated manually and weighed. Results from this example are given below in Table 3 which clearly shows that the polymers of the present invention are highly useful as a coating for MAP fertilizer particles in order to enhance abrasion resistance and decrease dust generation. The reference to the “H” polymer form refers to the fact that the carboxylic acid groups are still intact
TABLE 3
Coating
Level,
% Dust
Percent
after
Fertilizer Type
Coating
W/W, As-Is
Shaking
Granular MAP
None
N/A
0.43
Granular MAP
ARR-MAZ KGA500
0.52
0.29
Granular MAP
High charge polymer, mostly H
0.5
none
form, 60% solids
Granular MAP
High charge polymer, mostly H
1
none
form, 60% solids
Granular MAP
High charge polymer, mostly H
1.5
none
form, 60% solids
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Biodegradable anionic polymers are disclosed which include recurring polymeric subunits preferably made up of dicarboxylic monomers such as maleic anhydride, itaconic anhydride or citraconic anhydride. Free radical polymerization is used in the synthesis of the polymers. The polymers may be complexed with ions and/or mixed with fertilizers or seeds to yield agriculturally useful compositions. The preferred products of the invention may be applied foliarly or to the earth adjacent growing plants in order to enhance nutrient uptake by the plants.
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part of International Application No. PCT/KR2009/001975, filed Apr. 16, 2009, pending, which designates the U.S., published as WO 2010/067926, and is incorporated herein by reference in its entirety, and claims priority therefrom under 35 USC Section 120. This application also claims priority under 35 USC Section 119 from Korean Patent Application No. 10-2008-0124486, filed Dec. 9, 2008, in the Korean Intellectual Property Office, the entire disclosure of which is also incorporated herein by reference.
FIELD OF THE INVENTION
The present invention relates to a novel phosphoric compound, method for preparing the same, and flame retardant thermoplastic resin composition using the same.
BACKGROUND OF THE INVENTION
Thermoplastic resins can have excellent processability and mechanical properties and accordingly are used in the production of a variety of molded products. However, the thermoplastic resins can be easily burned by ignition sources and can spread fire. Therefore, thermoplastic resins used in housings of electronic heat-emitting products such as computers, facsimiles, and the like, should be treated to impart flame retardancy thereto.
Conventionally, a halogen-containing compound and an antimony-containing compound had been added to thermoplastic resins to impart flame retardancy. Examples of halogen-containing compounds include polybromodiphenyl ether, tetrabromobisphenol-A, epoxy compounds substituted with bromine, chlorinated polyethylene, and the like. Examples of the antimony-containing compounds include antimony trioxide and antimony pentoxide.
A halogen-containing compound and antimony-containing compound can impart flame retardancy to a thermoplastic resin with minimal deterioration of the physical properties thereof. Halogen-containing compounds such as polybromodiphenyl ether, however, can generate toxic hydrogen halide gases during molding processes. Therefore, there is an increased need for improving flame retardancy of thermoplastic resins without using halogen-containing compounds.
Phosphoric ester compounds can be used as a flame retardant for thermoplastic resins instead of a halogen-containing flame retardant. However, typically the phosphoric ester flame retardant must be used in such a large amount to provide adequate flame retardancy, which can negatively impact other physical properties of the thermoplastic resin.
SUMMARY OF THE INVENTION
Accordingly, in order to solve the problems of conventional phosphoric flame retardants, the present inventors have developed a novel phosphoric compound which can exhibit improved flame retardancy as compared to conventional phosphoric ester flame retardants. The novel phosphoric compound of the invention also does not generate toxic hydrogen halide gases.
The inventors have also developed a non-halogen compound containing flame retardant thermoplastic resin composition that can have excellent flame retardancy, which includes the novel phosphoric compound as a flame retardant. The composition of the invention can be more eco-friendly than conventional compositions including a halogen-containing flame retardant because the composition does not generate hydrogen halide gases during processing or combustion of the resin composition. In exemplary embodiments, the thermoplastic resin composition can include an aromatic vinyl polymer resin and a polyphenylene ether resin, which embodiment can also exhibit good moldability as well flame retardancy because the amount of polyphenylene ether resin used can be reduced.
The phosphoric compound of the invention is represented by the following Chemical Formula 1:
wherein R 1 and R 2 are the same or different and are independently C 1 -C 6 alkyl or aryl; and each m is the same or different and is independently an integer of 1 to 3.
In exemplary embodiments of the present invention, R 1 may be phenyl and each R 2 may be C 1 -C 6 alkyl.
In exemplary embodiments of the present invention, the phosphoric compound may be bis(4-tert-butylphenyl)phenyl phosphonate or bis(2,4,6-trimethylphenyl)phenyl phosphonate.
The present invention also provides a method for preparing the phosphoric compound represented by Chemical Formula 1. The method comprises reacting a compound, or a combination of compounds, represented by following Chemical Formula 4 with a compound represented by following Chemical Formula 5 in the presence of an organic amine compound.
In Chemical Formula 4, each R 2 is independently C 1 -C 6 alkyl or aryl; and m is an integer of 1 to 3.
In Chemical Formula 5, R 1 is C 1 -C 6 alkyl or aryl.
In exemplary embodiments of the present invention, the organic amine compound may be pyridine, triethylamine, or mixture thereof.
In exemplary embodiments of the present invention, the molar ratio of the compound represented by Chemical Formula 4 to the compound represented by Chemical Formula 5 can be about 2:1 to about 3:1.
In exemplary embodiments of the present invention, the reaction molar ratio of the organic amine compound to the compound represented by Chemical Formula 5 can be about 2:1 to about 50:1.
In exemplary embodiments of the present invention, the method comprises the following steps: reacting the compound represented by Chemical Formula 4 with the compound represented by Chemical Formula 5 in the presence of an organic amine compound for about 10 to about 30 hours at a temperature of about 120 to about 160° C. while stirring and refluxing the reaction mixture; removing unreacted organic amine compound by depressurizing the reaction product obtained by the reaction; and filtering and drying the reaction product, from which the unreacted organic amine compound was removed, after washing the reaction product.
The present invention further provides to a flame retardant comprising the phosphoric compound represented by Chemical Formula 1.
The present invention also provides a flame retardant thermoplastic resin composition including the phosphoric compound represented by Chemical Formula 1 or a mixture thereof. In exemplary embodiments of the present invention, the composition comprises about 0.5 to about 30 parts by weight of the phosphoric compound represented Chemical Formula 1 or a mixture thereof, based 100 parts by weight of the thermoplastic resin.
In exemplary embodiments of the present invention, the phosphoric compound may be bis(4-tert-butylphenyl)phenylphosphonate, bis(2,4,6-trimethylphenyl)phenylphosphonate, or a mixture thereof.
The thermoplastic resin is especially not limited. In exemplary embodiments of the present invention, the thermoplastic resin may include an aromatic vinyl polymer resin, polyphenylene ether resin, polyphenylene sulfide resin, polycarbonate resin, polyolefin-based resin, polyester, polyamide, and the like. The thermoplastic resin may be used alone or in combination thereof.
In exemplary embodiments of the present invention, the thermoplastic resin may include (A) about 80 to about 95% by weight of an aromatic vinyl polymer resin and (B) about 5 to about 20% by weight of a polyphenylene ether resin.
In exemplary embodiments of the present invention, the thermoplastic resin may further include a flame retardant including (D1) an aromatic phosphoric acid ester compound, (D2) an alkyl phosphinic acid metal salt compound, or a mixture thereof. In exemplary embodiments of the present invention, the composition can include about 1 to about 25 parts by weight of (D1) the aromatic phosphoric acid ester compound, (D2) the alkyl phosphinic acid metal salt compound, or a mixture thereof, based on 100 parts by weight of the thermoplastic resin.
In exemplary embodiments of the present invention, the resin composition may further comprise one or more additives such as a plasticizer, heat stabilizer, oxidation inhibitor, anti-dripping agent, compatibilizer, light stabilizer, pigment, dye, inorganic filler, and the like, and combinations thereof.
In exemplary embodiments of the present invention, the first average combustion time of the resin composition measured in accordance with the UL 94 VB for specimens having a thickness of about ⅛″ can be less than 38 seconds.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a GC-MS chromatogram of phosphoric compound (C1) prepared in Example 1.
FIG. 2 is a 1 H-NMR spectrum of phosphoric compound (C1) prepared in Example 1.
FIG. 3 is a GC-MS chromatogram of phosphoric compound (C2) prepared in Example 2.
FIG. 4 is a 1 H-NMR spectrum of phosphoric compound (C2) prepared in Example 2.
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described more fully hereinafter in the following detailed description of the invention, in which some, but not all embodiments of the invention are described. Indeed, this invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements.
Phosphoric Compound
A phosphoric compound of the present invention is represented by the following Chemical Formula 1.
In Chemical Formula 1, R 1 and R 2 are the same or different and are independently C 1 -C 6 alkyl or aryl; and each m is the same or different and are independently an integer of 1 to 3.
The C 1 -C 6 alkyl may be linear or branched. Unless otherwise defined, as used herein, the term “aryl” refers to C 6 -C 20 aryl or C 1 -C 6 alkyl-substituted C 6 -C 20 aryl.
In exemplary embodiments of the present invention, R 1 may be phenyl and each R 2 may be C 1 -C 6 alkyl. For example, each R 2 can be C 1 -C 2 alkyl and each m can be 2 or 3, for example 3.
In exemplary embodiments, R 1 is phenyl, each R 2 is branched C 3 -C 6 alkyl, for example tert-butyl, and m is 1. Exemplary embodiments of the phosphoric compound represented by the Chemical Formula 1 include without limitation bis(4-tert-butylphenyl)phenyl phosphonate represented by the following Chemical Formula 2 and bis(2,4,6-trimethylphenyl)phenyl phosphonate represented by the following Chemical Formula 3.
Method for Preparing the Phosphoric Compound
The phosphoric compound of the present invention can be prepared by reacting the compound, or a combination of compounds, represented by Chemical Formula 4 with the compound represented by Chemical Formula 5 in the presence of an organic amine compound as shown in the following Reaction Equation 1. Specifically, the phosphoric compound of the Chemical Formula 1 can be prepared by dehydrochlorination reaction of the compound represented by Chemical Formula 4 and the compound represented by Chemical Formula 5.
In Reaction Equation 1, each R 1 and R 2 is independently C 1 -C 6 alkyl or aryl as defined herein; and m is an integer of 1 to 3.
Exemplary compounds represented by Chemical Formula 4 may include, but are not limited to, 4-tert-butyl phenol, 2,4,6-trimethyl phenol, and the like, and combinations thereof. Exemplary compounds represented by Chemical Formula 5 may include, but are not limited to, phenylphosphonic dichloride.
The organic amine compound promotes the dehydrochlorination reaction, removes HCl, which is a by-product of the dehydrochlorination reaction, and at the same time works like solvent. Exemplary embodiments of the organic amine compound may include, but are not limited to, pyridine, triethylamine, and the like, and mixtures thereof.
In exemplary embodiments of the present invention, a reaction molar ratio of the compound represented by Chemical Formula 4 to the compound represented by Chemical Formula 5 may be about 2:1 or more. In other exemplary embodiments of the present invention, a reaction molar ratio of the compound represented by Chemical Formula 4 to the compound represented by Chemical Formula 5 may be about 2:1. However, because some of the compounds represented by Chemical Formula 4 may not participate in the reaction due to vaporization during reaction, the reaction molar ratio of the compound represented by Chemical Formula 4 to the compound represented by Chemical Formula 5 may be about 2:1 or more, for example about 2:1 to about 3:1 to prevent this problem.
The organic amine compound may be used in an excess amount based on 1 mole of the compound represented by Chemical Formula 5. In exemplary embodiments, the reaction molar ratio of the organic amine compound to the compound represented by Chemical Formula 5 may be about 2:1 to about 50:1, for example, the reaction molar ratio of the organic amine compound to the compound represented by Chemical Formula 5 may be about 2:1 to about 10:1. When the organic amine compound is used in an amount of less than about 2 moles based on 1 mole of the compound represented by Chemical Formula 5, the dehydrochlorination reaction may not proceed smoothly and it can be difficult to remove HCl by-product. Although the maximum value of the reaction molar ratio of the organic amine compound to the compound represented by Chemical Formula 5 is not particularly limited, typically the invention will not exceed 50 molar ratio to reduce manufacturing costs and costs for collecting unreacted organic amine compound.
In exemplary embodiments of the present invention, the method comprises: reacting the compound, or a combination of compounds, represented by Chemical Formula 4 with the compound represented by Chemical Formula 5 at a temperature of about 120 to about 160° C. for about 10 to about 30 hours, for example about 20 to about 27 hours, while stirring and refluxing the reaction mixture.
In exemplary embodiments of the present invention, the compound, or a combination of compounds, represented by Chemical Formula 4 can be reacted with the compound represented by Chemical Formula 5 while stirring and refluxing the reaction mixture, and then the phosphoric compound represented by Chemical Formula 1 can be formed by the dehydrochlorination reaction as mentioned above. HCl, which is a by-product of the dehydrochlorination reaction, can bond with the organic amine compound and thereby form an organic amine hydrochloride.
In another exemplary embodiment of the present invention, the method may further comprise removing the unreacted organic amine compound and the organic amine hydrochloride from the reaction product obtained by the dehydrochlorination reaction.
The unreacted organic amine compound can be removed by depressurizing the reaction product including the phosphoric compound represented by Chemical Formula 1, the organic amine hydrochloride and the unreacted organic amine compound. In this case, the reaction product can be depressurized using a rotary distillation apparatus at room temperature.
After the unreacted organic amine compound is removed by the depressurizing process, the reaction product can be washed filtered and dried. For example, water can be added to the reaction product, from which the unreacted organic amine compound is removed, the resulting solution can be stirred for about 0.5 to about 2 hours and filtered, the organic amine hydrochloride present in the reaction product can be dissolved in water and removed, and the phosphoric compound represented by Chemical Formula 1, which is insoluble in water and in the form of solid, can be obtained. Water present in the phosphoric compound represented by Chemical Formula 1 can be completely removed using the depressurizing oven, or other suitable means.
Flame Retardant Thermoplastic Resin Composition
The present invention provides a flame retardant thermoplastic resin composition using the phosphoric compound represented by the Chemical Formula 1. The resin composition comprises the thermoplastic resin and the phosphoric compound represented by Chemical Formula 1 or a mixture thereof.
In exemplary embodiments of the present invention, the flame retardant thermoplastic resin composition comprises about 100 parts by weight of the thermoplastic resin, and about 0.5 to about 30 parts by weight, for example about 2 to about 25 parts by weight, and as another example about 2.5 to about 20 parts by weight, of the phosphoric compound represented by Chemical Formula 1 or a mixture thereof, based on 100 parts by weight of the thermoplastic resin.
In some embodiments, the phosphoric compound represented by Chemical Formula 1 or a mixture thereof may be present in an amount of about 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, or 30 parts by weight. Further, according to some embodiments of the present invention, the amount of the phosphoric compound represented by Chemical Formula 1 or a mixture thereof can be in a range from about any of the foregoing amounts to about any other of the foregoing amounts.
When the flame retardant thermoplastic resin composition includes the phosphoric compound represented by Chemical Formula 1 or a mixture thereof in an amount of less than about 0.5 parts by weight, the resin composition may not obtain sufficient flame retardancy. On the other hand, when the amount of the phosphoric compound represented by Chemical Formula 1 or a mixture thereof is more than about 30 parts by weight, fundamental properties of the resin composition may be deteriorated.
Examples of the thermoplastic resin used in the present invention are not especially limited. Examples of the thermoplastic resin can include, without limitation, aromatic vinyl polymer resins, polyphenylene ether resins, polyphenylene sulfide resins, polyalkyl(meth)acrylate resins, polycarbonate resins, polyolefin-based resins, polyester resins, polyamide resins, and the like, and combinations thereof may be used.
Examples of the aromatic vinyl polymer resin may include without limitation polystyrene resin (PS), rubber modified polystyrene resin (HIPS), aromatic vinyl-vinyl cyanide graft copolymer resin (ABS), vinyl cyanide-aromatic vinyl copolymer resin (SAN), and the like, and combinations thereof. Examples of the polyolefin-based resin may include without limitation polyethylene, polypropylene, and the like, and combinations thereof. Examples of the polyester resin may include without limitation polyethylene terephthalate, polybutylene terephthalate, and the like, and combinations thereof. Examples of the polyalkyl(meth)acrylate resin may include without limitation polymethylmethacrylate (PMMA) resin, and the like, and combinations thereof.
In exemplary embodiments, the thermoplastic resin may include an aromatic vinyl polymer resin such as polystyrene resin (PS), rubber modified polystyrene resin (HIPS), aromatic vinyl-vinyl cyanide graft copolymer resin (such as an acrylonitrile-butadiene-styrene or ABS resin), or vinyl cyanide-aromatic vinyl copolymer resin (such as a styrene-acrylonitrile or SAN resin); polyphenylene ether resin, polyphenylene sulfide resin, polycarbonate resin, polyethylene resin, polypropylene resin, polyethylene terephthalate, polybutylene terephthalate, polymethylmethacrylate resin, polyamide resin, and the like may be used. The thermoplastic resin may be used alone or in combination thereof.
In exemplary embodiments of the present invention, the resin composition comprises a mixture comprising (A) an aromatic vinyl polymer resin and (B) a polyphenylene ether resin as the thermoplastic resin. For example, the resin composition can include 100 parts by weight of a mixture comprising (A) about 80 to about 95% by weight of the aromatic vinyl polymer resin and (B) about 5 to about 20% by weight of the polyphenylene ether resin, and about 0.5 to about 30 parts by weight of the phosphoric compound represented by Chemical Formula 1 or a mixture thereof.
In some embodiments, the aromatic vinyl polymer resin may be present in an amount of about 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, or 95% by weight. Further, according to some embodiments of the present invention, the amount of the aromatic vinyl polymer resin can be in a range from about any of the foregoing amounts to about any other of the foregoing amounts.
In some embodiments, the polyphenylene ether resin may be present in an amount of about 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20% by weight. Further, according to some embodiments of the present invention, the amount of the polyphenylene ether resin can be in a range from about any of the foregoing amounts to about any other of the foregoing amounts.
In some embodiments, the phosphoric compound represented by Chemical Formula 1 or a mixture thereof may be present in an amount of about 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, or 30 parts by weight. Further, according to some embodiments of the present invention, the amount of the phosphoric compound represented by Chemical Formula 1 or a mixture thereof can be in a range from about any of the foregoing amounts to about any other of the foregoing amounts.
(A) Aromatic Vinyl Polymer Resin.
In exemplary embodiments of the present invention, the aromatic vinyl polymer resin (A) may be a homopolymer of an aromatic vinyl monomer or a copolymer of one or more aromatic vinyl monomers and optionally one or more rubber monomers. Also, the aromatic vinyl polymer resin (A) can further comprise one or more other monomers, such as a (meth)acrylic acid alkyl ester monomer, unsaturated nitrile (also referred to herein as vinyl cyanide) monomer, and the like, and mixtures thereof.
Examples of the aromatic vinyl monomer include without limitation styrene, α-methyl styrene, para-methyl styrene, and the like. The aromatic vinyl monomer may be used singly or in the form of combinations of two or more thereof. In exemplary embodiments, the aromatic vinyl monomer includes styrene.
The (meth)acrylic acid alkyl ester monomer can be a (meth)acrylic acid alkyl ester having a C1 to C10 alkyl group. Examples of the (meth)acrylic acid alkyl ester monomer may include without limitation methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, pentyl methacrylate, hexyl methacrylate, heptyl methacrylate, octyl methacrylate, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, pentyl acrylate, hexyl acrylate, heptyl acrylate, octyl acrylate, ethyl hexyl acrylate and the like. The (meth)acrylic acid alkyl ester monomer may be used singly or in the form of combinations of two or more thereof.
Examples of the vinyl cyanide monomer include without limitation acrylonitrile, methacrylonitrile, ethacrylonitrile, and the like. The vinyl cyanide monomer may be used singly or in the form of combinations of two or more thereof. In exemplary embodiments, the vinyl cyanide monomer includes acrylonitrile.
In exemplary embodiments of the present invention, the aromatic vinyl polymer resin can include polystyrene resin (PS), rubber modified polystyrene resin (HIPS), aromatic vinyl-vinyl cyanide graft copolymer resin (ABS), vinyl cyanide-aromatic vinyl copolymer resin (SAN), and the like, and combinations thereof.
Examples of the rubber can include without limitation butadiene-based rubber, isoprene based rubber, a copolymer of butadiene and styrene, alkyl(meth)acrylate rubber, and the like, and mixtures thereof. The rubber can be present in an amount of about 3 to about 30% by weight, for example about 5 to about 15% by weight, based on the total weight of the aromatic vinyl polymer resin (A).
The aromatic vinyl monomer can be used in an amount of about 70 to about 97% by weight, for example about 85 to about 95% by weight, based on the total weight of the aromatic vinyl polymer resin (A).
The aromatic vinyl polymer resin (A) may also include other monomer(s) such as but not limited to vinyl cyanide monomers such as acrylonitrile, acrylic acid, methacrylic acid, maleic acid anhydride, N-substituted maleimide, and the like, in order to impart properties such as chemical resistance, processability, flame retardancy, and the like. The other monomer maybe used in an amount of about 40% by weight or less, based on the total weight of the aromatic vinyl polymer resin (A).
The aromatic vinyl polymer resin (A) can be manufactured by polymerization in the presence of a polymerization initiator or by thermal polymerization without a polymerization initiator. Examples of the polymerization initiator include without limitation peroxide-based initiators such as benzoyl peroxide, t-butyl hydroperoxide, acetyl peroxide, cumen hydroperoxide, and the like; azo-based initiators such as azobisisobutyronitrile, and the like; and combinations thereof.
The aromatic vinyl polymer resin (A) can manufactured using conventional techniques, such as but not limited to bulk polymerization, suspension polymerization, emulsion polymerization, and the like, and combinations thereof.
In the blend comprising the aromatic vinyl polymer resin (A) and the polyphenylene ether resin (B), the size of the rubber phase particle can be about 0.1 to about 2.0 μm for the best properties.
The mixture of the aromatic vinyl polymer resin (A) and the polyphenylene ether resin (B) can include the aromatic vinyl polymer resin (A) in an amount of about 80 to about 95% by weight, for example about 80 to about 90% by weight, based on the total weight of (A)+(B). In some embodiments, the aromatic vinyl polymer resin may be present in an amount of about 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 919, 92, 93, 94, or 95% by weight. Further, according to some embodiments of the present invention, the amount of the aromatic vinyl polymer resin can be in a range from about any of the foregoing amounts to about any other of the foregoing amounts.
(B) Polyphenylene Ether Resin
In exemplary embodiments of the present invention, a polyphenylene ether resin (B) can be used in combination with the aromatic vinyl polymer resin (A) which can improve flame retardancy and heat resistance of the thermoplastic resin composition.
Examples of the polyphenylene ether resin (B) include without limitation poly(2,6-dimethyl-1,4-phenylene)ether, poly(2,6-diethyl-1,4-phenylene)ether, poly(2,6-dipropyl-1,4-phenylene)ether, poly(2-methyl-6-ethyl-1,4-phenylene)ether, poly(2-methyl-6-propyl-1,4-phenylene)ether, poly(2-ethyl-6-propyl-1,4-phenylene)ether, poly(2,6-diphenyl-1,4-phenylene)ether, copolymer of poly(2,6-dimethyl-1,4-phenylene)ether and poly(2,3,6-trimethyl-1,4-phenylene)ether, copolymer of poly(2,6-dimethyl-1,4-phenylene)ether and poly(2,3,5-triethyl-1,4-phenylene)ether, and the like. The polyphenylene ether resin may be used alone or in combination thereof. In exemplary embodiments, a copolymer of poly(2,6-dimethyl-1,4-phenylene)ether and poly(2,3,6-trimethyl-1,4-phenylene)ether or poly(2,6-dimethyl-1,4-phenylene)ether can be used.
The degree of polymerization of the polyphenylene ether resin (B) is not limited. In exemplary embodiments, the degree of polymerization of the polyphenylene ether resin measured in chloroform solvent at 25° C. can be about 0.2 to about 0.8 in view of heat stability and workability of the thermoplastic resin composition.
The mixture of aromatic vinyl polymer resin (A) and polyphenylene ether resin (B) can include the polyphenylene ether resin (B) in amount of about 5 to about 20% by weight, for example about 10 to about 20% by weight, based on the total weight of (A)+(B). In some embodiments, the polyphenylene ether resin may be present in an amount of about 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20% by weight. Further, according to some embodiments of the present invention, the amount of the polyphenylene ether resin can be in a range from about any of the foregoing amounts to about any other of the foregoing amounts.
When the amount of the polyphenylene ether resin (B) is less than about 5% by weight, flame retardancy of the resin composition may be deteriorated. On the other hand, when the amount of the polyphenylene ether resin (B) is more than about 20% by weight, moldability of the resin composition may be deteriorated.
In other exemplary embodiments of the present invention, the thermoplastic resin composition may further include an aromatic phosphoric acid ester compound (D1), an alkyl phosphinic acid metal salt compound (D2), or a mixture thereof, in order to improve flame retardancy.
The thermoplastic resin composition may include the aromatic phosphoric acid ester compound (D1), alkyl phosphinic acid metal salt compound (D2), or mixture thereof in amount of about 1 to about 25 parts by weight, for example about 5 to about 20 parts by weight, and as another example about 10 to about 15 parts by weight, based on 100 parts by weight of the thermoplastic resin. In some embodiments, the thermoplastic resin composition may include the aromatic phosphoric acid ester compound (D1), alkyl phosphinic acid metal salt compound (D2), or mixture thereof in an amount of about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, or 25 parts by weight. Further, according to some embodiments of the present invention, the amount of the aromatic phosphoric acid ester compound (D1), alkyl phosphinic acid metal salt compound (D2), or mixture thereof can be in a range from about any of the foregoing amounts to about any other of the foregoing amounts.
When the amount of the aromatic phosphoric acid ester compound (D1), alkyl phosphinic acid metal salt compound (D2), or mixture thereof is less than about 1 part by weight, the resin composition may not obtain sufficient flame retardancy. On the other hand, when the amount of the aromatic phosphoric acid ester mixture (D1), alkyl phosphinic acid metal salt compound (D2), or mixture thereof is more than about 25 parts by weight, properties such as impact strength may be deteriorated.
(D1) Aromatic Phosphoric Acid Ester Compound
The aromatic phosphoric acid ester compound (D1) that can be used in the thermoplastic resin composition according to exemplary embodiments of the present invention can have a structure of the following Chemical Formula 6.
In Chemical Formula 6, R 3 , R 4 , and R 5 are the same or different and are independently hydrogen or C 1 -C 4 alkyl; X is C 6 -C 20 aryl or C 1 -C 4 alkyl-substituted C 6 -C 20 aryl and is derived from dialcohol of resorcinol, hydroquinol, or bisphenol-A; and n is an integer of 0 to 4.
Examples of the aromatic phosphoric acid ester compound (D1) are as follows. When n is 0 in Chemical Formula 6, examples of the compound represented by Chemical Formula 6 include without limitation triphenyl phosphate, tri(2,6-dimethyl) phosphate, and the like. When n is 1 in Chemical Formula 6, examples of the compound represented by Chemical Formula 6 include without limitation resorcinol bis(diphenyl) phosphate, resorcinol bis(2,6-dimethylphenyl) phosphate, resorcinol bis(2,4-ditertiarybutylphenyl) phosphate, hydroquinol bis(2,6-dimethylphenyl) phosphate, hydroquinol bis(2,4-ditertiarybutylphenyl) phosphate, and the like. The aromatic phosphoric acid ester compound can be used alone or in combination thereof.
(D2) Alkyl Phosphinic Acid Metal Salt Compound
The alkyl phosphinic acid metal salt compound (D2) that can be used in the thermoplastic resin composition according to exemplary embodiments of the present invention can have a structure of the following Chemical Formula 7.
In Chemical Formula 7, each R is the same or different and is independently C 1 -C 6 alkyl, C 4 -C 6 cycloalkyl, or C 6 -C 10 aryl; M is a metal of Al, Zn, Mg or Ca; and n is an integer of 2 or 3.
In exemplary embodiments, each R is independently methyl, ethyl, propyl, butyl or phenyl, and M is Al or Zn.
An example of the alkyl phosphinic acid metal salt compound (D2) may include without limitation diethyl phosphinic acid aluminum metal salt.
The average diameter of the alkyl phosphinic acid metal salt compound (D2) can be about 10 μm or less, for example about 0.01 to about 10 μm. When the average diameter of the alkyl phosphinic acid metal salt compound (D2) is more than about 10 μm, the impact strength and flame retardancy of the resin composition may be deteriorated. On the other hand, when the average diameter of the alkyl phosphinic acid metal salt compound (D2) is less than about 0.01 μm, it may be difficult to make the product, and the extrusion or injection processability of the resin composition may be deteriorated.
In other exemplary embodiments of the present invention, the thermoplastic resin composition may further include one or more additives, depending on its use. Examples of the additives may include without limitation plasticizers, heat stabilizers, antioxidants, anti-dripping agents, compatibilizers, light-stabilizers, pigments, dyes, inorganic fillers, and the like. Examples of the inorganic fillers may include without limitation asbestos, glass fibers, talc, ceramic, sulfates, and the like. The additives can be used alone or in combination thereof. The thermoplastic resin composition of the invention can include one or more additives in an amount of about 30 parts by weight or less, for example about 0.001 to about 30 parts by weight, based on 100 parts by weight of the thermoplastic resin.
The thermoplastic resin composition according to the present invention can be manufactured by conventional methods known in the art. In exemplary embodiments, after the above-stated components are mixed with (optional) additives, the thermoplastic resin composition can be manufactured in the form of pellets by melt extruding in an extruding machine.
The flame retardant thermoplastic resin composition according to the present invention can be used in the manufacture of various products due to its excellent flame retardancy. For example, the flame retardant thermoplastic resin composition can be used to produce exterior materials for electric/electronic goods such as housings for televisions, computers, audio equipment, air conditioners, office automation equipment, and the like, to which strict flame retardancy regulations are required.
The method for preparing the plastic products from the flame retardant thermoplastic resin composition according to the present invention is not limited. For example, the products can be made using conventional molding processes known in the art, such as extrusion molding, injection molding, blow molding, casting molding, and the like. These methods can be easily carried out by a person of ordinary skill in the art.
The invention may be better understood by reference to the following examples which are intended for the purpose of illustration and are not to be construed as in any way limiting the scope of the present invention, which is defined in the claims appended hereto.
EXAMPLES
Example 1
Preparation of a Phosphoric Compound (C1)
4-tert-butyl phenol (60 g, 0.40 mol), phenyl phosphonic dichloride (43 g, 0.20 mol), and pyridine (400 mL, 4.97 mol) are added into a reactor, refluxed and stirred at 140° C. for about 20 hours. The temperature of the reactor is cooled down to room temperature and then the unreacted pyridine is removed by depressurizing the reaction product using a rotary distillation apparatus. 500 mL of distilled water is added into the reaction product, which is in the form of solid by removing the unreacted pyridine, the resulting solution is stirred for 1 hour to dissolve pyridine hydrochloride produced during the reaction in the water layer, and the resulting solution is filtered to obtain a water-insoluble solid compound (C1). The filtered solid compound (C1) is dried for 24 hours in an oven under reduced pressure to obtain a pure white solid of bis(4-tert-butylphenyl)phenyl phosphonate (C1) (79 g, yield: 96%). The resultant compound (C1) is analyzed by GC-MS and 1 H-NMR, and the results are shown in FIGS. 1 and 2 , respectively.
Example 2
Preparation of a Phosphoric Compound (C2)
2,4,6-trimethyl phenol (54 g, 0.40 mol), phenyl phosphonic dichloride (43 g, 0.20 mol), and pyridine (400 mL, 4.97 mol) are added into a reactor, refluxed, and stirred at 140° C. for about 20 hours. The temperature of the reactor is cooled down to room temperature and then the unreacted pyridine is removed by depressurizing the reaction product using a rotary distillation apparatus. 500 mL of distilled water is added into the reaction product, which is in the form of solid by removing the unreacted pyridine, the resulting solution is stirred for 1 hour to dissolve pyridine hydrochloride produced during the reaction in the water layer, and the resulting solution is filtered to obtain a water-insoluble solid compound (C2). The filtered solid compound (C2) is dried for 24 hours in an oven under reduced pressure to obtain a pure white solid of bis(2,4,6-trimethylphenyl)phenyl phosphonate (C2) (75.7 g, yield: 96%). The resultant compound (C2) is analyzed by GC-MS and 1 H-NMR, and the results are shown in FIGS. 3 and 4 , respectively.
Preparation of Flame Retardant Thermoplastic Resin Composition
Specifications of each components used in the following examples and comparative examples are as follows.
(A) Aromatic Vinyl Polymer Resin
Rubber modified styrene resin made by Cheil Industries Inc. of Korea (product name: HG-1760S) is used.
(B) Polyphenylene Ether Resin
Poly(2,6-dimethyl-1,4-phenylene)ether made by Mitsubishi Engineering Plastic Company of Japan (product name: PX-100F) is used.
(C) Phosphoric Compound
(C1) Bis(4-tert-butylphenyl)phenyl phosphonate prepared in Example 1 is used.
(C2) Bis(2,4,6-trimethylphenyl)phenyl phosphonate prepared in Example 2 is used.
(D1) Aromatic Phosphoric Acid Ester Compound
Bis(dimethylphenyl) phosphate bisphenol A made by Daihachi Chemical Industry Co., Ltd. of Japan (product name: CR741S) is used.
(D2) Alkyl Phosphinic Acid Metal Salt Compound
Diethyl Phosphinic acid aluminum metal salt made by Clariant Company (product name: Exolit OP930) is used. The average diameter is 5 μM.
Examples 3 to 8
The components are added into a conventional mixer in an amount as described in the following Table 1, and the mixture is extruded through a conventional twin screw extruder at a temperature range of 200 to 280° C. to prepare a product in pellet form. The pellets are dried at 80° C. for 2 hours and then molded into test specimens in a 6 oz injection molding machine at 180 to 280° C. with a mold temperature of 40 to 80° C.
The flame retardancy is measured in accordance with UL 94 VB for the specimens having a thickness of about ⅛″. The results of Examples 3 to 8 are shown in Table 1.
Comparative Examples 1 to 2
Comparative Examples 1 to 2 are prepared in the same manner as the Examples above except each component is used in a different amount. The results of Comparative Examples 1 to 2 are shown in Table 1.
TABLE 1
Comparative
Examples
Examples
3
4
5
6
7
8
1
2
(A)
85
85
85
85
85
85
85
85
(B)
15
15
15
15
15
15
15
15
(C)
(C1)
20
—
5
—
2.5
—
—
—
(C2)
—
20
—
5
—
2.5
—
—
(D)
(D1)
—
—
15
15
10
10
20
15
(D2)
—
—
—
—
2.5
2.5
—
5
First average combustion
37.5
23.0
27.7
20.9
15.2
8.5
41.3
41.5
time (⅛″, sec)
Second average combustion
27.0
24.7
24.5
23.8
19.8
15.1
31.5
10.2
time (⅛″, sec)
As shown in Table 1, it can be seen that Examples 3 to 4 using only the flame retardant phosphoric compound of the invention and Examples 5 to 8 using the flame retardant phosphoric compound of the invention as well as a conventional phosphoric flame retardant exhibit excellent flame retardant properties, as compared to Comparative Examples 1 to 2 using only a conventional phosphoric flame retardant.
Many modifications and other embodiments of the invention will come to mind to one skilled in the art to which this invention pertains having the benefit of the teachings presented in the foregoing description. Therefore, it is to be understood that the invention is not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention being defined in the claims.
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The present invention provides a novel phosphoric compound, a method for preparing the same, and a thermoplastic resin composition including the same. A thermoplastic resin composition comprising the phosphoric compound of the present invention can have excellent flame retardancy, and can be eco-friendly because the phosphoric compound does not generate toxic gas during molding or combustion.
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CROSS REFERENCE TO RELATED APPLICATIONS
This application is a continuation as to all subject matter common to U.S. application Ser. No. 851,995 filed Nov. 16, 1977, now abandoned, by Avilino Sequeira, Jr. John D. Begnaud and Frank L. Barger and assigned to Texaco Inc., assignee of the present invention, and a continuation in-part for additional subject matter.
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to control systems and methods in general and, more particularly, to control systems and methods for oil refining units.
SUMMARY OF THE INVENTION
A furfural refining unit treats medium sweet charge oil with a furfural solvent in a refining tower to yield raffinate and extract mix. The furfural is recovered from the raffinate and from the extract mix and returned to the refining tower. A system controlling the refining unit includes a gravity analyzer, a flash point temperature analyzer, a sulfur analyzer, a refractometer and viscosity analyzers. The analyzers analyze the medium sweet charge oil and provide corresponding signals. Sensors sense the flow rates of the charge oil and the furfural flowing into the refining tower and the temperature of the extract-mix and provide corresponding signals. The flow rate of the medium sweet charge oil or the furfural is controlled in accordance with the signals provided by all the sensors and the analyzers while the other flow rate of the medium sweet charge oil or the furfural is constant.
The objects and advantages of the invention will appear more fully hereinafter from a consideration of the detailed description which follows, taken together with the accompanying drawings wherein one embodiment of the invention is illustrated by way of example. It is to be expressly understood, however, that the drawings are for illustration purposes only and are not to be construed as defining the limits of the invention.
DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a furfural refining unit in partial schematic form and a control system, constructed in accordance with the present invention, in simple block diagram form.
FIG. 2 is a detailed block diagram of the control means shown in FIG. 1.
FIGS. 3 through 14 are detailed block diagrams of the H computer, the K signal means, the H signal means, the KV computer, the VI signal means, the SUS computer, the SUS 210 computer, the W computer, the VI DWC .sbsb.O computer, the VI DWC .sbsb.P computer, the A computer and the J computer, respectively, shown in FIG. 2.
DESCRIPTION OF THE INVENTION
An extractor 1 in a furfural refining unit is receiving medium sweet charge oil by way of a line 4 and furfural solvent by way of a line 7 and providing raffinate to recovery by way of a line 10, and an extract mix to recovery by way of a line 14.
Medium sweet charge oil is a charge oil having a sulfur content equal to or less than a predetermined sulfur content and having a kinematic viscosity, corrected to a predetermined temperature, less than a first predetermined kinematic viscosity but equal to or less than a second predetermined kinematic viscosity. Preferable, the predetermined sulfur content is 1.0%, the predetermined temperature is 210° F., and the first and second predetermined kinematic viscosities are 7.0 and 15.0, respectively. The temperature in extractor 1 is controlled by cooling water passing through a line 16. A gravity analyzer 20, flash point analyzer 22 and viscosity analyzers 23 and 24, a refractometer 26 and a sulfur analyzer 28 sample the charge oil in line 4 and provide signals API, FL, KV 210 , KV 150 and S, respectively, corresponding to the API gravity, the flash point, the kinematic viscosities at 210° F. & 150° F., the refraction index and sulfur content, respectively.
A flow transmitter 30 in line 4 provide a signal CHG corresponding to the flow rate of the charge oil in line 4. Another flow transmitter 33 in line 7 provides a signal SOLV corresponding to the furfural flow rate. A temperature sensor 38, sensing the temperature of the extract mix leaving extractor 1, provides a signal T corresponding to the sensed temperature. All signals hereinbefore mentioned are provided to control means 40.
Control means 40 provides signal C to a flow recorder controller 43. Recorder controller 43 receives signals CHG and C and provides a signal to a valve 48 to control the flow rate of the charge oil in line 4 in accordance with signals CHG and C so that the charge oil assumes a desired flow rate. Signal T is also provided to temperature controller 50. Temperature controller 50 provides a signal to a valve 51 to control the amount of cooling water entering extractor 1 and hence the temperature of the extract-mix in accordance with its set point position and signal T.
The following equations are used in practicing the present invention for medium sweet charge oil:
H.sub.210 =lnln(KV.sub.210 +C.sub.1) 1.
where H 210 is a viscosity H value for 210° F., KV 210 is the kinematic viscosity of the charge oil at 210° F. and C 1 is a constant having a preferred value of 0.6.
H.sub.150 =lnln(KV.sub.150 +C.sub.1) 2.
where H 150 is a viscosity H value for 150° F., and KV 150 is the kinematic viscosity of the charge oil at 150° F.
K.sub.150 =[C.sub.2 -ln(T.sub.150 +C.sub.3 ]/C.sub.4 3.
where K 150 is a constant needed for estimation of the kinematic viscosity at 100° F., T 150 is 150, and C 2 through C 4 are constants having preferred values of 6.5073, 460 and 0.17937, respectively.
H.sub.100 =H.sub.210 +(H.sub.150 -H.sub.210)/K.sub.150 4.
where H 100 is a viscosity H value for 100° F.
kv.sub.100 =exp[exp(H.sub.100)]-C.sub.1 5.
where KV 100 is the kinematic viscosity of the charge oil at 100° F.
sus=c.sub.5 (kv.sub.210)+[c.sub.6 +c.sub.7 (kv.sub.210)]/[c.sub.8 +c.sub.9 (kv.sub.210)+c.sub.10 (kv.sub.210).sup.2 +c.sub.11 (kv.sub.210).sup.3 ](c.sub.12) 6.
where SUS is the viscosity in Saybolt Universal Seconds and C 5 through C 12 are constants having preferred values of 4.6324, 1.0, 0.03264, 3930.2, 262.7, 23.97, 1.646 and 10 -5 , respectively.
SUS.sub.210 =[C.sub.13 +C.sub.14 (C.sub.15 -C.sub.16)]SUS 7.
where SUS 210 is the viscosity in Saybolt Universal Seconds at 210° F. and C 13 through C 16 are constants having preferred values of 1.0, 0.000061, 210 and 100, respectively.
W=C.sub.43 -C.sub.45 API+C.sub.45 /KV.sub.210 -C.sub.46 S+C.sub.47 (API).sup.2 -C.sub.48 API/KV.sub.210 +C.sub.49 (S)(API), 8.
where W is the percent wax in the charge oil, and C 43 through C 49 are constants having preferred values of 51.17 4.3135, 182.83, 5.2388, 0.101, 6.6106 and 0.19609, respectively.
VI.sub.DWC.sbsb.O =C.sub.50 -C.sub.51 RI+C.sub.52 (RI)(VI)+C.sub.53 (FL)(API)-C.sub.54 (W)(VI), 9.
where C 50 through C 54 are constants having preferred values of 2306.54, 1601.786, 1.33706, 0.00945 and 0.20915, respectively.
VI.sub.DWC.sbsb.P =VI.sub.DWC.sbsb.O +(Pour)[C.sub.21 -C.sub.22 lnSUS.sub.210 +C.sub.23 (InSUS.sub.210).sup.2 ] 10.
where VI DWC .sbsb.P and Pour are the viscosity index of the dewaxed product at a predetermined temperature and the Pour Point of the dewaxed product, respectively, and C 21 through C 23 are constants having preferred values of 2.856, 1.18 and 0.126, respectively.
ΔVI=VI.sub.RO -V.sub.DWC.sbsb.O =VI.sub.RP -VI.sub.DWC.sbsb.P 11.
where VI RO and VI RP are the VI of the dewaxed refined oil at 0° F., and the predetermined temperature, respectively.
A=C.sub.55 -C.sub.56 (API)+C.sub.57 (FL)(KV.sub.210), 12.
where C 55 through C 57 are constants having preferred values of 860.683, 28.9516 and 0.02389, respectively.
J={{-C.sub.58 A+{(C.sub.58 A).sup.2 -4C.sub.59 A(C.sub.60 +C.sub.81 √T-ΔVI)}.sup.1/2 }/2C.sub.59 A}.sup.2 13.
where J is the furfural dosage and C 58 through C 61 are constants having preferred values of 0.013795, -0.00025376, -18.233 and 1.1031, respectively.
C=(SOLV) (100)/J 14.
where C is the new charge oil flow rate.
Referring now to FIG. 2, signal KV 210 is provided to an H computer 50 in control means 40, while signal KV 150 is applied to an H computer 50A. It should be noted that elements having a number and a letter suffix are similar in construction and operation as to those elements having the sane numeric designation without a suffix. All elements in FIG. 2, except elements whose operation is obvious, will be disclosed in detail hereinafter. Computers 50 and 50A provide signals E 1 and E 2 corresponding to H 210 and H 150 , respectively, in equations 1 and 2, respectively, to H signal means 53. K signal means 55 provides a signal E 3 corresponding to the term K 150 in equation 3 to H signal means 53. H signal means 53 provides a signal E 4 corresponding to the term H 100 in equation 4 to a KV computer 60 which provides a signal E 5 corresponding to term KV 100 in accordance with signal E 4 and equation 5 as hereinafter explained.
Signals E 5 and KV 210 are applied to VI signal means 63 which provides a signal E 6 corresponding to the viscosity index.
An SUS computer 65 receives signal KV 210 and provides a signal E 7 corresponding to the term SUS in accordance with the received signals and equation 6 as hereinafter explained.
An SUS 210 computer 68 receives signal E 7 and applies signal E 8 corresponding to the term SUS 210 in accordance with the received signal and equation 7 as hereinafter explained.
A W computer 69 receives signals KV 210 , S and API and provides a signal E 9 corresponding to the term W in equation 8 in accordance with the received signals and equation 8 as hereinafter explained.
A VI DWC .sbsb.O computer 70 receives signals RI, E 9 , API, FL and E 6 and provides a signal E 10 corresponding to the term VI DWC .sbsb.O in accordance with the received signals and equation 9 as hereinafter explained.
A VI DWC .sbsb.P computer 72 receives signal E 8 and E 10 and provides a signal E 11 corresponding to the term VI DWC .sbsb.P in accordance with the received signals and equation 10. Subtracting means 76 performs the function of equation 11 by subtracting signal E 11 from a direct current voltage V 9 corresponding to the term VI RP , in equation 11, to provide a signal E 12 corresponding to the term ΔVI in equation 11.
An A computer 79 receives signals KV 210 , API and FL and provides a signal A corresponding to the term A in equation 12, in accordance with the received signals and equation 12 as hereinafter explained.
A J computer 80 receives signals T, E 11 and E 12 and provide a signal E 13 corresponding to the term J in accordance with the received signals and equation 12 as hereinafter explained to a divider 83.
Signal SOLV is provided to a multiplier 82 where it is multiplied by a direct current voltage V 2 corresponding to a value of 100 to provide a signal corresponding to the term (SOLV) (100) in equation 13. The product signal is applied to divider 83 where it is divided by signal E 13 to provide signal C corresponding to the desired new charge oil flow rate.
It would be obvious to one skilled in the art that if the charge oil flow rate was maintained constant and the furfural flow rate varied, equation 14 would be rewritten as
SO=(J) (CHG)/100 15.
where SO is the new solvent flow rate. Control means 40 would be modified accordingly.
Referring now to FIG. 3, H computer 50 includes summing means 112 receiving signal KV 210 and summing it with a direct current voltage C 1 to provide a signal corresponding to the term [KV 210 +C 1 ] shown in equation 1. The signal from summing means 112 is applied to a natural logarithm function generator 113 which provides a signal corresponding to the natural log of the sum signal which is then applied to another natural log function generator 113A which in turn provides signal E 1 .
Referring now to FIG. 4, K signal means 55 includes summing means 114 summing direct current voltage T 150 and C 3 to provide a signal corresponding to the term [T 150 +C 3 ] which is provided to a natural log function generator 113B which in turn provides a signal corresponding to the natural log of the sum signal from summing means 114. Subtracting means 115 subtracts the signal provided by function generator 113B from a direct current voltage C 2 to provide a signal corresponding to the numerator of equation 3. A divider 116 divides the signal from subtracting means 115 with a direct current voltage C 4 to provide signal E 3 .
Referring now to FIG. 5, H signal means 53 includes subtracting means 117 which subtracts signal E 1 from signal E 2 to provide a signal, corresponding to the term H 150 -H 210 , in equation 4, to a divider 118. Divider 118 divides the signal from subtracting means 117 by signal E 3 . Divider 114 provides a signal which is summed with signal E 1 by summing means 119 to provide signal E 4 corresponding to H 100 .
Referring now to FIG. 6, a direct current voltage V 3 is applied to a logarithmic amplifier 120 in KV computer 60. Direct current voltage V 3 corresponds to the mathematical constant e. The output from amplifier 120 is applied to a multiplier 122 where it is multiplied with signal E 4 . The product signal from multiplier 122 is applied to an antilog circuit 125 which provides a signal corresponding to the term exp (H 100 ) in equation 5. The signal from circuit 125 is multiplied with the output from logarithmic amplifier 120 by a multiplier 127 which provides a signal to antilog circuit 125A. Circuit 125A provides a signal to subtracting means 128 which subtracts a direct current voltage C 1 from the signal from circuit 125A to provide signal E 5 .
Referring now to FIG. 7, VI signal means 63 is essentially memory means which is addressed by signals E 5 , corresponding to KV 100 , and signal KV 210 . In this regard, a comparator 130 and comparator 130A represent a plurality of comparators which receive signal E 5 and compare signal E 5 to reference voltages, represented by voltages R 1 and R 2 , so as to decode signal E 5 . Similarly, comparators 130B and 130C represent a plurality of comparators receiving signal KV 210 which compare signal KV 210 with reference voltages RA and RB so as to decode signal KV 210 . The outputs from comparators 130 and 130B are applied to an AND gate 133 whose output controls a switch 135. Thus, should comparators 130 and 130B provide a high output, AND gate 133 is enabled and causes switch 135 to be rendered conductive to pass a direct current voltage V A corresponding to a predetermined value, as signal E 6 which corresponds to VI. Similarly, the outputs of comparators 130 and 130C control an AND gate 133A which in turn controls a switch 135A to pass or to block a direct current voltage V B . Similarly, another AND gate 133B is controlled by the outputs from comparators 130A and 133B is controlled by the outputs from comparators 130A and 130B to control a switch 135B so as to pass or block a direct current voltage V C . Again, an AND gate 133C is controlled by the outputs from comparators 130A and 130C to control a switch 135C to pass or to block a direct current voltage V D . The outputs of switches 135 through 135C are tied together so as to provide a common output.
Referring now to FIG. 8, the SUS computer 65 includes multipliers 136, 137 and 138 multiplying signal KV 210 with direct current voltages C 9 , C 7 and C 5 , respectively, to provide signals corresponding to the terms C 9 (KV 210 ), C 7 (KV 210 ) and C 5 (KV 210 ), respectively in equation 6. A multiplier 139 effectively squares signal KV 210 to provide a signal to multipliers 140 141. Multiplier 140 multiplies the signal from multiplier 139 with a direct current voltage C 10 to provide a signal corresponding to the term C 10 (KV 210 ) 2 in equation 6. Multiplier 141 multiplies the signal from multiplier 139 with signal KV 210 to provide a signal corresponding to (KV 210 ) 3 . A multiplier 142 multiplies the signal from multiplier 141 with a direct current voltage C 11 to provide a signal corresponding to the term C 11 (KV 210 ) 3 in equation 6. Summing means 143 sums the signals from multipliers 136, 140 and 142 with a direct current voltage C 8 to provide a signal to a multiplier 144 where it is multiplied with a direct current voltage C 12 . The signal from multiplier 137 is summed with a direct current voltage C 6 by summing means 145 to provide a signal corresponding to the term [C 6 +C 7 (KV 210 )]. A divider 146 divide the signal provided by summing means 145 with the signal provided by multiplier 144 to provide a signal which is summed with the signal from multiplier 138 by summing means 147 to provide signal E 7 .
Referring now to FIG. 9, SUS 210 computer 68 includes subtracting means 148 which subtracts a direct current voltage C 16 from another direct current voltage C 16 from another direct current voltage C 15 to provide a signal corresponding to the term (C 15 -C 16 ) in equation 7. The signal from subtracting means 148 is multiplied with a direct current voltage C 14 by a multiplier 149 to provide a product signal which is summed with another direct current voltage C 13 by summing means 150. Summing means 150 provides a signal corresponding to the term [C 13 +C 14 (C 15 -C 16 ] in equation 7. The signal from summing means 150 is multiplied with signal E 7 by a multiplier 152 to provide signal E 8 .
Referring now to FIG. 10, there is shown W computer 69 having multipliers 155, 156 and 157 receiving signal API. Multiplier 155 multiplies signal API with signal S to provide a product signal to another multiplier 160 where it is multiplied with a direct current voltage C 49 to provide a signal corresponding to the term C 49 (S) (API) in equation 8. Multiplier 156 effectively squares signal API and provides a signal to another multiplier 163 where it is multiplied with a direct current voltage C 47 to provide a signal corresponding to the term (C 47 ) (API) 2 . Multiplier 157 multiplies signal API with a direct current voltage C 44 to provide a signal corresponding to the term C 44 (API). A divider 166 divides signal API with signal KV 210 to provide another signal to a multiplier 168 where it is multiplied with a direct current voltage C 48 which in turn provides a signal corresponding to the term [C 48 (API)/(KV 210 )] in equation 8. A divider 170 divides a direct current voltage C 45 with signal KV 210 to provide a signal corresponding to the term C 45 /(KV 210 ). A multiplier 173 multiplies signal S with a direct current voltage C 46 . Summing means 175 sums a direct current voltage C 43 with the signals provided by multipliers 160, 163 and divider 170. Other summing means 176 sums the signals provided by multipliers 157, 168 and 173. Subtracting means 179 subtracts the signal provided by summing means 176 from the signal provided by summing means 175 to provide signal E 9 .
Referring now to FIG. 11, VI DWC .sbsb.O computer 70 includes a multiplier 180 receiving signals E 6 , E 9 and providing a product signal to another multiplier 182 where it is multiplied with a direct current voltage C 54 Multiplier 182 provides a signal corresponding to the term C 54 (W) (VI) in equation 9. Another multiplier 185 multiplies signal RI with a direct current voltage C 51 to provide a signal corresponding to the term (C 51 ) (RI). Summing means 188 sums the signals from multipliers 182, 185.
A multiplier 190 multiplies signals E 6 and RI to provide a product signal to another multiplier 193 where it is multiplied with a direct current voltage C 52 . Multiplier 193 provides a product signal to summing means 198. Another multiplier 200 multiplies signals FL and API to provide a product signal to a multiplier 202 where it is multiplied with a direct current voltage C 53 . Multiplier 322 provides a signal corresponding to the term C 53 (FL) (API) in equation 9 to summing means 198 where it is summed with the signal from multiplier 315 and a direct current voltage C 50 to provide a sum signal. Subtracting means 205 subtracts the sum signal provided by summing means 188 from the signal provided by summing means 198 to provide signal E 10 .
VI DWC .sbsb.P computer 72 shown in FIG. 12, includes a natural logarithm function generator 200 receiving signal E 8 and providing a signal corresponding to the term lnSUS 210 to multipliers 201 and 202. Multiplier 201 multiplies the signal from function generator 200 with a direct current voltage C 22 to provide a signal corresponding to the term C 22 ln SUS 210 in equation 10. Multiplier 202 effectively squares the signal from function generator 200 to provide a signal that is multiplied with the direct current voltage C 23 by a multiplier 205. Multiplier 205 provides a signal corresponding to the term C 23 (ln SUS 210 ) 2 in equation 10. Subtracting means 206 subtracts the signals provided by multiplier 201 from the signal provided by multiplier 205. Summing means 207 sums the signal from subtracting means 206 with a direct current voltage C 21 . A multiplier 208 multiplies the sum signals from summing means 207 with a direct current voltage POUR to provide a signal which is summed with signal E 9 by summing means 210 which provides signal E 11 .
Referring now to FIG. 13, A computer 79 includes a multiplier 212 multiplying signal API with a direct current voltage C 56 to provide a signal corresponding to the term C 56 (API) in equation 12. Another multiplier 213 multiplies signals FL and KV 210 to provide a product signal to a multiplier 215 where it is multiplied with a direct current voltage C 57 . Multiplier 215 provides a product signal corresponding to the term C 57 (FL) (KV 210 ) in equation 12 to summing means 218. Summing means 218 sums the signal provided by multiplier 215 with a direct current voltage C 55 to provide a sum signal. Subtracting means 220 subtracts the signal provided by multiplier 212 from the sum signal provided by summing means 218 to provide signal A.
Referring now to FIG. 14, J computer 80 includes multipliers 225 and 226 multiplying signal A with direct current voltages C 58 and C 59 respectively. Multiplier 228 effectively squares the signal provided by multiplier 225 to provide a signal corresponding to the term (C 58 A) 2 to subtracting means 234. Multiplier 235 multiplies the signal from multiplier 226 with a direct current voltage V 4 corresponding to a value of 4 to provide a product signal to another multiplier 236.
A square root circuit 240 receives signal T and provides a signal corresponding to (T) 1/2 to a multiplier 243 where it is multiplied with a direct current voltage C 61 . Multiplier 243 provides a product signal to subtracting means 247 where signal E 12 corresponding to ΔVI is subtracted from it to provide a difference signal. Summing means 250 sums the difference signal from subtracting means 367 with direct current voltage C 60 to provide a signal corresponding to the term [C 60 +C 61 (T) 1/2 -ΔVI] in equation 13 to multiplier 236. Multiplier 236 multiplies the signal provided by multiplier 235 with the signal provided by summing means 250 to provide a signal to subtracting means 234 where it is subtracted from the signal provided by multiplier 228. Subtracting means 234 provides a difference signal to a square root circuit 256 which provides a signal to subtracting means 260. Subtracting means 260 subtracts the signal provided by multiplier 225 from the signal provided by square root circuit 256 to provide a signal to a divider 263. A multiplier 265 multiplies a direct current voltage V 23 , corresponding to a value of 2, with the signal provided by multiplier 226 to provide a product signal to divider 263 where it is divided into the signal provided by subtracting means 260. Divider 383 provides signal E 13 .
The present invention is hereinbefore described controls a furfural refining unit receiving medium sweet charge oil to achieve a desired charge oil flow rate for a constant furfural flow rate. It is also within the scope of the present invention, as hereinbefore described, to control the furfural flow rate while the medium sweet charge oil flow is maintained at a constant rate.
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A furfural refining unit treates medium sweet charge oil with a furfural solvent in a refining tower to yield raffinate and extract mix. The furfural is recovered from the raffinate and from the extract mix and returned to the refining tower. A system controlling the refining unit includes a gravity analyzer, a refractometer and viscosity analyzer, all analyzing the medium sweet charge oil and providing corresponding signals, sensors sense the flow rates of the charge oil and the furfural flowing into the refining tower and the temperature of the extract mix and provide corresponding signals. One of the flow rates of the medium sweet charge oil and the furfural flow rates is controlled in accordance with the signals from all the analyzers and all the sensors, while the other flow rate of the medium sweet charge oil and the furfural flow rates is constant.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to identification and assistance. More specifically the present invention relates to identification primarily for the purposes of unlocking and entering a vehicle and assistance primarily in reminding a user of forgotten items.
[0003] 2. Background of the Invention
[0004] In today's ever-more demanding lifestyles, acts which were once simple and routine are becoming increasingly demanding. For example, one such act is getting into and starting a vehicle, and traveling somewhere without forgetting all that is needed to be brought on the travel. Some people forget or misplace keys while others find themselves carrying so much that the simple process of inserting a key and turning becomes a little more enduring. Other people have even found themselves locked out of their car while it is running, a frustrating situation no one wants to be in.
[0005] Unlocking and starting a vehicle is a very routine process for many people. Driving also requires more than just keys. In the United States, drivers must carry a driver's license and either vehicle registration or proof of insurance. Most drivers don't think of it this way though. Most drivers need their wallet, purse, phone, watch, personal data assistant (PDA), etc. These items may not let one into or start a car, but they are just as easy to leave behind for the same reason.
[0006] Recent advances designed to address the problems in this area include technology such as remote keyless entry or password type keyless entry. Keyless entry usually only means unlocking the vehicle. This has been taken to the next level with remote start vehicles, which can actually turn the engine on from a remote location. However, all of these methods still require some sort of physical device combined with an action in order to accomplish the task. Also, the remote technologies all use some sort of wireless code, like a radio frequency (RF), which can be unlocked by an unauthorized user.
[0007] In the meantime wireless technology continues to grow. What has begun with simple radio frequencies has spawned into WI-FI and BLUETOOTH, which are each capable of high security encryption. BLUETOOTH has been featured in many small electronic devices including cellular telephones and accessories, Global Positioning System (GPS) units, PDA's, etc. Radio frequency identification (RFID) is not quite as secure as WI-FI or BLUETOOTH, but each RFID tag is unique and detectable up to about twenty feet. The general advantage of RFID does not lie in its security, but the actual RFID tag is very small and can be less than paper thin. Some recent developments in RFID technology have even led to a tattoo-like tag, which is merely printed on the surface of an item making it very thin and unnoticeable.
[0008] What is needed in the art is a method of entering a vehicle that is more convenient than current methods and without the need for any one single item. Also, a method of making sure a driver has all the necessary equipment he or she needs before driving is needed. This method should make use of all the new advances in wireless technology including WI-FI, BLUETOOTH, and RFID.
SUMMARY OF THE INVENTION
[0009] The present invention includes wireless communication among multiple items as a method of determining identity and a method of reminding a user of missing items. Unlocking a vehicle will no longer be a problem because using various embodiments of this invention a vehicle can detect a user as the user approaches the vehicle. The user's identity is detected by the personal items the user is carrying such as a watch, cellular telephone, PDA, laptop computer, etc. While no single item can get the job done, as a security measure, the combination of all the items lets the vehicle know that its owner is near. Once the identity has been determined the vehicle unlocks, starts, even open its driver side door or trunk for the user. Not only does this greatly benefit the user, but the vehicle can then take another step and remind the user of essential items the vehicle did not find, even for a given date. Items such as golf clubs on Sundays, or a granola bar on weekdays can be programmed by the user so the user does not forget them when such items should accompany the user.
[0010] Furthermore, the present invention is not limited to vehicles, but can be used at any point of security or other place where a user may find it beneficial to have a reminder of forgotten items. A user may even have one in a vehicle which also controls the user's house, office, computer database, etc. Because the number of items necessary for identification has no limit, it has application in military, correctional, and other top security functions as well.
[0011] In one exemplary embodiment, the present invention is an identification system which comprises a wireless communication device and a plurality of items possessing unique wireless identifiers. Unique wireless identifiers are already present in many electronic devices such as PDA's, laptops, cellular telephones, etc. which commonly possess BLUETOOTH or WI-FI technology. Those items which do not already possess unique wireless identifiers can have them added using the latest in RFID technology, which takes the form of a “tattoo” which can literally be printed on the surface of an item. This gives the user a vast selection of personal belongings to require for identification, making it very hard for a potential imposter to have any idea which items the potential imposter needs to fake the user's identification.
[0012] In another exemplary embodiment, the present invention is a reminder system designed to assist a user when the user has forgotten a necessary or desired item. This is a great solution for those mornings when a user is running late and does not have time to make sure he or she has everything needed for that particular day. Once the user reaches the car a wireless communication device issues an aural or visual reminder of the items the user is missing. The user programs the wireless communication device with a plurality of setup forms which are stored in a database. Users are encouraged to create many setup forms to be reminded of many things such as a laptop every weekday, or reading glasses before going to the office.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 shows a system for determining identity according to an exemplary embodiment of the present invention.
[0014] FIG. 2 shows a screen shot of a software program used to setup identification according to an exemplary embodiment of the present invention.
[0015] FIG. 3 shows a flow chart for a process of determining identity according to an exemplary embodiment of the present invention.
[0016] FIG. 4 shows a system for reminding a user of missing items according to an exemplary embodiment of the present invention.
[0017] FIGS. 5A-D show screen shots of a software program used to personalize a reminder system according to an exemplary embodiment of the present invention.
[0018] FIG. 6 shows a flow chart for a process of reminding a user of missing items according to an exemplary embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0019] The present invention includes wireless communication among multiple items as a technique for determining identity and a method of reminding a user of missing items. The user preprograms a wireless communication device to detect his or her items as the user gains access to a vehicle, house, locker, office, safe, encrypted data files, or other point of security. These items all have unique wireless identifiers. Once a minimum number of the user's items have been detected the wireless communication device allows entry or operation. If any of the user's required items are missing, the wireless detection device reminds the user of the missing items. The wireless communication device uses a broad range of wireless communication methods including, but not limited to, BLUETOOTH, WI-FI, and RFID, and combinations thereof.
[0020] As used in this disclosure, “wireless communication” refers to any wireless transmission or detection. “Wireless communication” includes both one-way and two-way communication. The term “item” and its variations are used throughout this disclosure to describe a vast majority of tangible belongings. Though it is not a technical term it is meant to encompass any and all possible physical belongings that a user may have either to determine the user's identity, or simply wish to be reminded when it is missing. Wireless transmitters get smaller as technology evolves, and since RFID transmitters can now be less than paper thin, the term “item” potentially describes any physical object. Examples to outline the breadth of this term include, but are not limited to, clothing, equipment, collectables, disposables, consumables, etc. Even pets are candidates for unique wireless identifiers. “Point of security”, as used in this disclosure, refers to any secure enclosure or encrypted data such as of the type requiring a key, combination, password, or any other method of limiting access to certain individuals. “Points of security” include homes, vehicles, lockers, safes, data files, and even prisons.
[0021] In one exemplary embodiment, shown in FIG. 1 , the present invention is a system of secure keyless entry. This embodiment features a system for identification based on a wireless communication device capable of detecting multiple items through wireless communication, then comparing the items with a database to determine the user's identity. The wireless communication device can be incorporated into a vehicle, house, locker, or any other point of security. The wireless communication device can even control remote points of security through wireless communication.
[0022] FIG. 1 shows a wireless communication device 102 that is incorporated into a vehicle 120 . Wireless communication device 102 also communicates wirelessly to a plurality of items 112 and other points of security including a house 122 , a locker 124 , and a safe 126 . Wireless communication device 102 works with an antenna 104 to communicate using BLUETOOTH, WI-FI, RFID, or any other wireless communication protocol in the art. A setup form 214 is shown in FIG. 2 , where user 110 enters the items to be identified. The user's name is entered in box 230 . Box 232 shows a list of currently detected items that are within a detectable range of wireless communication device 102 . This range will vary with the wireless protocol used. For instance, an item with an RFID tag needs to be within about twenty feet, but an item with a WI-FI transmitter can be detected from much farther away. From the list of currently detected items, user 110 can drag and drop to box 234 any items that the user feels is necessary to establish the user's identity. User 110 may not wish to be forced to carry all of the items in box 234 to gain entry, so the user may specify a minimum amount of items the user feels are necessary to establish identity. For example, user 110 usually has a wallet, watch, cellular telephone, PDA, and a camera. If user 110 is running late, and has forgotten the camera but has the other four items, user 110 will not want to be forced to find the camera in order to unlock the car. Once identity is established, user 110 is entitled to the privileges selected from box 238 , such as unlocking and starting vehicle 120 . Since wireless communication device 102 can communicate with house 122 , user 110 may also choose to unlock the house or open the garage door from the privileges in box 238 .
[0023] Alternatively, the user 110 can set up the system to ensure that a specific portion of a vehicle 120 (house 122 or other) opens whenever a specific tag or series of tags is recognized. For example, whenever a briefcase, laptop bag or large box is recognized by the system, the trunk of the vehicle 120 may be programmed to open automatically to ensure ease of placement of the recognized item into the trunk.
[0024] In another exemplary embodiment, the system may be set up to recognize RFID tags when the user 110 is leaving the vehicle 120 and alert the user 120 whenever an item has been left behind that should not be. For example, a briefcase or cellular telephone may have been inadvertently left behind, and the user 110 may be alerted to this before the user 110 is too far from the vehicle 120 . Other examples include but are not limited to briefcases, food, pets, food, gifts, etc. The present system can prevent the dreaded forgotten leftover food that is inadvertently left in a vehicle overnight.
[0025] Setup form 214 is one of many user 110 can specify. User 110 is encouraged to complete many setup forms for each user, and even multiple setup forms per user. For instance, user 110 may have a wallet, watch, cellular telephone, PDA, and a camera on weekdays, but on the weekend user 110 doesn't carry all of those items. Instead user 110 has a wallet and watch, is wearing sandals and a baseball cap, and carries a cigar cutter. User 110 may complete another setup form for the weekend. User 110 may even set up a particular list of items needed for a particular trip, either a vacation or a business meeting. The system could even be set up to run a particular profile depending on the detection of a particular tagged item, such as the running of the beach/weekend profile upon detection of a flip-flops. The possibilities are endless. The setup forms are not necessarily exclusive to specific days however; the user may gain entry by carrying the required items for either setup form at any time. Once user 110 has completed setup form 214 , it is stored in database 106 with all the other complete setup forms. User 110 can complete setup forms for each other user, while specifying different items and privileges for each other user.
[0026] A flow chart for an identification process 108 performed by wireless communication device 102 is shown in FIG. 3 . First, wireless communication device 102 seeks 341 all the items within range. The seeking action can be initiated by the press of a button or some other pre-designated event. Such event can, include, for example, a user walking up to a vehicle, or entering a vehicle. Other such trigger events are also possible and within the scope of the present invention. Next, wireless communication device 102 checks 342 database 106 for a setup form that matches the criteria for detected items. When wireless communication finds a setup form that matches the found items, it checks 343 to see if enough items are present to determine an identity based on the criteria in boxes 234 and 236 of a setup form. If there are not enough items present to determine identity, wireless communication device 102 issues a reminder 344 . This reminder can be aural, visual, or both. Once the user has gathered all necessary items the user can send wireless communication device 102 back into “seek” mode 341 . The detected items match a setup form 342 and wireless communication device 102 then checks to see if enough items are detected 343 to establish identity. If enough items are detected the wireless communication device then allows all of the privileges in box 238 . Wireless communication device 102 then checks to see if all the items are present 345 . If less than all of the items are present wireless communication device 102 will still issue a reminder 346 just before activating the privileges. Alternatively, wireless communication device 102 can constantly search for items, and allow privileges as soon as it finds a match. In this manner, user 110 can trigger an event 347 , such as simply walk toward vehicle 120 while wireless communication device 102 auto detects user 110 's items and has already unlocked and started the car by the time user 110 reaches vehicle 120 . This includes a process requiring no action at all by user 110 provided user 110 is in possession of all necessary items.
[0027] In another exemplary embodiment, shown in FIG. 4 , the present invention is a system for reminding a user of missing items. In this embodiment the wireless communication device detects multiple items through wireless detection, and then compares the items found with a database to determine which items, if any, are missing.
[0028] The system includes a wireless communication device 402 , which works together with an antenna 404 , a database 406 , and a reminding process 409 . A user 410 completes at least one setup form 416 where user 410 can specify items the user will need or want upon a specified trigger event. The specified event can be every morning when the car 420 is unlocked, every Sunday morning when the car is started, one time next Tuesday when the car is unlocked, or even any time at the press of a button simply for the user's peace of mind. Upon the specified event, wireless communication device 402 attempts to detect a single or plurality of items 412 through wireless communication. This list is pulled from the appropriate form 416 . If less than the single or plurality of items 412 are detected, wireless communication device issues a reminder. This reminder can be a human voice specifying which from the single or plurality of items 412 are missing, a visual alert and a picture of the item(s), or both.
[0029] Sample setup forms 516 A-D are shown in FIGS. 5A-D , where user 410 enters the items of which to be reminded. The user's name is entered in box 530 . Box 532 shows a list of currently detected items that are within a detectable range of wireless communication device 402 . This range will vary with the wireless protocol used. For instance, an item with an RFID tag needs to be within about twenty feet, but an item with a WI-FI transmitter can be detected from and up to approximately 0.3-1.0 miles away. From the list of currently detected items, user 410 can drag and drop to box 534 the items of which user 410 would like to be reminded. An event is to be specified in boxes 537 and 539 . This is the event upon which wireless communication device 402 performs the reminding process 409 . Box 537 allows user 410 to select a frequency of the reminder, such as “every”, “next”, “every other”, etc., while box 539 allows user 410 to select a time, act, or any other event upon which wireless communication device 402 is capable of acting, such as “Sunday”, “July 4 th ”, “Weekday”, “Press of a button”, “Vehicle Ignition”, etc. The combination of boxes 537 and 539 create a phrase such as “Every Wednesday”, “Next July 4 th ”, “Every other Vehicle Ignition”, etc. Once user 410 has completed setup form 416 , it is stored in database 406 . User 410 can complete a setup form for each instance of reminder user 410 desires. User 410 is encouraged to create many reminders for any and all events the user may desire a reminder. User 410 may also create reminders for each other user while specifying different items to be reminded of at specified events for the other users.
[0030] A flow chart for a reminding process 409 performed by wireless communication device 402 is shown in FIG. 6 . First, an event 651 from a setup form triggers wireless communication device 402 to detect 652 present items through wireless communication. Once the items have been detected, they are compared with the items in box 534 of the triggering setup form. If all of the items from box 534 have been detected 653 , then wireless communication device 402 issues, for example, a visual or aural alert 655 to user 410 that all items have been found. If less than all of the items in box 534 are detected, then wireless communication device 402 issues a visual or aural warning 654 that user 410 does not have all the items that appear in box 534 . For example, in FIG. 5A , user Bob has completed a setup form to ensure that he has his cellular telephone, watch, wallet, PDA, and laptop computer. Bob has specified that he needs to have this reminder every weekday. Only Monday and Tuesday can be seen, but the box is scrollable and the other selected days are hidden in this view. When Bob approaches his vehicle on weekdays wireless communication device 402 will seek Bob's cellular telephone, watch, wallet, PDA, and laptop computer and remind him if anything is missing. FIG. 5D shows a setup form completed by a user named Alice. As can be seen from boxes 532 and 534 , Alice has RFID tags on all of her belts. She has completed this setup form to remind her to wear a belt on weekdays. She has over seven belts, but needs only one per day. Box 536 contains the number “one” so that wireless communication device 402 is satisfied after finding only one belt.
[0031] The foregoing disclosure of the exemplary embodiments of the present invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many variations and modifications of the embodiments described herein will be apparent to one of ordinary skill in the art in light of the above disclosure. The scope of the invention is to be defined only by the claims appended hereto, and by their equivalents.
[0032] Further, in describing representative embodiments of the present invention, the specification may have presented the method and/or process of the present invention as a particular sequence of steps. However, to the extent that the method or process does not rely on the particular order of steps set forth herein, the method or process should not be limited to the particular sequence of steps described. As one of ordinary skill in the art would appreciate, other sequences of steps may be possible. Therefore, the particular order of the steps set forth in the specification should not be construed as limitations on the claims. In addition, the claims directed to the method and/or process of the present invention should not be limited to the performance of their steps in the order written, and one skilled in the art can readily appreciate that the sequences may be varied and still remain within the spirit and scope of the present invention.
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Systems and methods are disclosed which relate to identification and reminding. A wireless communication device is mounted at a point of security such as a car. When a user wishes to enter or start the car, the wireless communication device detects nearby items through wireless communication. These items, which possess wireless transmitters, are compared with an internal database to determine the identity of the user. Once the identity has been determined, the user can then be reminded of missing items.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to size reduction of particles of explosives. More particularly, the invention pertains to an improved method for rapidly and safely grinding explosive materials to a small particle size with reduced variation in particle size distribution.
2. State of the Art
Size reduction of explosive materials has historically been accomplished by either (a) dissolution and recrystallization under carefully controlled conditions, or (b) grinding of the dry explosive. Grinding equipment such as fluid energy mills or jet mills are typically used. These grinders have no moving parts in contact with the material undergoing size reduction. The particles are ground by fluid jets which cause the particles to travel in a "racetrack" course, so that the particle size is reduced by interparticle collision. Alternatively, ball mills or pin mills are used. Nevertheless, the use of fluid-energy mills and other dry grinding methods for explosives is considered to be inherently hazardous. Excessive energy input into a single particle may result in catastrophic detonation. Such high explosives as cyclotrimethylenetrinitramine (RDX) and cyclotetramethylenetetranitramine (HMX) are considered to be too dangerous to be used in the pure form in ammunition. Various desensitizing agents are combined with the explosive materials which enable their use in ammunition and useful detonable products.
Even with insensitive materials such as coal, steam is used as a carrier in production scale fluid-energy mills to minimize the risk of spontaneous combustion and possible explosion.
Wet grinding, i.e. grinding of a slurry of the solid material in an "inert" liquid such as water, is considered to be much less dangerous, because the liquid lubricates the solids and readily absorbs energy.
U.S. Pat. No. 3,239,502 of Lee et al. describes one method currently used for preparing cyclotetramethylenetetranitramine (HMX) of small particle size, i.e. less than 325 mesh. Crude HMX is diluted with a non-solvent liquid such as water, methanol, ethanol or the like. The resultant slurry is recirculated by passage through a piping system including a pump or pumps, and throttling valves or orifices. The recirculating treatment is conducted for a period of at least 10 (ten) hours to gently grind the HMX particles. A cyclone separator is used to separate the desired fines from the larger particles. The latter are returned to the grinding circuit for additional size reduction. The grinding period is very long, typically about 16 hours, and there is considerable batch to batch variation in mean particle size as well as in the distribution of particle size.
More recently, ultrasonic energy has been proposed for size reduction of coal. For example, U.S. Pat. No. 4,156,593 Tarpley Jr. describes the size reduction of coal particles for separating contaminants such as pyrite and clay therefrom. Coal is slurried in an aqueous liquid containing a leaching agent and a penetrant/embrittling agent. Fragmentation in the presence of ultrasonic cavitation is facilitated by the natural porosity of coal.
U.S. Pat. No. 4,410,423 of Walsh describes the use of ultrasonic energy to enhance the acid dissolution of sodium fluoride and cryolite. Alkaline ore containing the sodium fluoride, cryolite, and insoluble alumina is reduced in particle size by dissolution of the fluoride and cryolite. However, the released alumina particles and carbon particles in the slurry are not reduced in size by the ultrasonic treatment.
Generation of an ultrasonic field in liquids may result in cavitation capable of producing high local pressures, i.e. several tens of thousands of atmospheres. It is believed that the gas bubbles which are created have high internal temperatures as well, e.g. 5000 to 10,000 degrees C. Microscopic flames are known to occur in the liquid, and the ultrasonic treatment has been shown to ionize water, degrade organic compounds, melt metals, and erode solid surfaces. Sonification is also known to significantly increase the detonation rates of explosives.
The high explosives RDX and HMX are known to be particularly sensitive to impact, with impact sensitivities of 0.45 and 0.52 kgm, respectively. When the conditions are such that a gas may be adiabatically compressed, with a rapid increase in temperature, and subsequently collapsed, the sensitivity of the explosive material is known to be enhanced. Such conditions are known to exist, and are in fact desirably created, in liquids subjected to ultrasonic generation.
SUMMARY OF THE INVENTION
This invention is a method for grinding solid explosive particles such as energetic nitramines to smaller sizes. In this method, the particles are suspended in a liquid to form a slurry. The slurry is subjected to ultrasonic energy at a frequency or frequencies in the range of about 14-60 KHz. The preferred ultrasonic frequency is in the lower end of the scale, i.e. about 14-30 KHz, where cavitational shock intensity is higher. It may be desirable, however, to utilize the higher frequencies with some explosive materials to reduce the cavitational intensity and avoid detonation.
The slurrying medium is inert, that is, it does not react chemically with the explosive material being ground. Furthermore, it is also a non-solvent as regards the desired explosive material. The slurrying medium, preferably aqueous, may contain additives which react with and/or dissolve contaminants associated with the explosive material. The contaminants, for example may comprise materials found in the crude explosive, including occluded acidity and other undesirable substances.
The method of the invention has demonstrated significant advantages over other methods used to grind explosive materials. Use of ultrasonic grinding is much faster than other methods. Final particle size is easily controlled, and is more uniform than the product of other methods currently in use. In addition, the risk of detonation is believed to be much reduced. The input power is easily controlled to accommodate differences in particle hardness and sensitivity of various explosive materials.
Ultrasonic grinding of wet slurries is generally applicable to solid explosive per se, including those considered to be "high explosive" materials. It has been demonstrated as a method for grinding high explosives cyclotrimethylenetrinitramine (RDX), tetramethylenetetranitramine (HMX) and a mixture of RDX and HMX known as "co-produced explosive" (CPX).
In tests, class 1 RDX in which about 70 percent passed a #325 U.S. Standard sieve was ground to class 5 RDX, in which 97 percent passed the #325 sieve, in a mere 30 minutes. The conventional wet-grinding technique takes more than 10 hours.
Wet sonification of explosive materials in accordance with this invention is particularly advantageous when the final product is to be formulated from wet explosives. The method elminates a drying step as well as the dry grinding step with its attendant hazards.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a partial sectional view through an ultrasonic energy generating device by which the present invention may be practiced.
FIG. 2 is a schematic view of the ultrasonic apparatus used in the tests described herein.
FIG. 3 is a graphical representation of the resulting particle size from grinding slurried samples of particulate melamine, RDX and CPX for various periods of time.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 illustrates a typical ultrasonic generating apparatus 10 which may be useful for continous sonic grinding of a particulate explosive material. The sonic generator 12 includes a transducer 14 and sonic converter 16 which convert electrical energy to ultrasonic vibration in the tip 18 of disruptor horn 20. The particular construction and operation of such generators is well known in the art. The disruptor horn 20 is shown submerged in the slurry 22 of particulate explosive material within treatment chamber 24. A stream 26 of slurry 22 is introduced into the treatment chamber 24 from inlet conduit 28. A stream 30 of ground explosive material slurry 32 passes through orifice 34 in orifice plate 36 into outlet conduit 38. The orifice is sized to permit the finely ground particles to pass through, retaining the larger, unground particles to remain in the treatment chamber 24.
If desired, the flowrate of slurry into the treatment chamber 24 may be adjusted to increase the liquid level 40 so that a portion 42 of the slurry overflows from the treatment chamber through overflow conduit 44. It may be recycled for further grinding or used for a different end product.
The tip 18 of the horn 20 is located so that all particles passing into the outlet conduit 38 are subjected to the high intensity ultrasonic field below the tip, where the primary acoustic cavitation occurs. Preferably, the tip 18 is located a maximum distance of about 1.0D from the orifice plate 36, where D is the diameter of the tip 18.
In an alternate continuous treatment method, the treatment chamber 24 has only an inlet located at the bottom of the chamber 24, and an outlet on the side of the chamber 24. Thus, looking at FIG. 1, the flow path is reversed, i.e. the slurry is fed upward through conduit 38 into treatment chamber 24, and the ground slurry passes from the chamber 24 through conduit 28. The particles in the incoming slurry are immediately subjected the acoustic cavitation upon passing upward through orifice 34 into the treatment chamber. In this alternate system, overflow conduit 44 is generally unnecessary, and is removed.
Because of the heat generated by sonification, the treatment apparatus will generally require cooling means, not shown, to prevent the bulk slurry temperature from exceeding a safe limit. For some explosives like HMX, RDX and CPX, the bulk slurry temperature in the ultrasonic treatment chamber is preferably maintained below 50 degrees C. This temperature will vary with the particular explosive material. The cooling means may comprise cooling coils in the treatment chamber walls, or surrounding the walls, or other means known in the art.
Ultrasonic generators in current use generally have a zirconate titanate crystal or transducer for generating large ultrasonic amplitudes with small power inputs at frequencies of about 14-60 KHz. The preferred frequency is between 14 and 30 KHZ, and the most preferred is 14-30 l KHZ. The ultransonic waves travelling through the liquid consist of alternate compressions and rarefactions, which at high amplitude, create acoustic cavitation, i.e. the making and breaking of gas bubbles which abrade and grind the solid particles to smaller sizes. Bubble collapse may create high local pressure of about 20,000 atmospheres if permitted to resonate. The bubble size is greater at the lower frequencies, e.g. 14 -30 KHZ, resulting in greater mechanical shock upon collapse. At higher frequencies such as 1 MHz, the shock intensity is much reduced. Acoustic cavitation may not be possible at frequencies above 2.5 MHz.
The slurry stream 30 passing from the ultrasonic treatment is typically filtered or otherwise treated to separate the ground particulate explosive materials from the inert slurry liquid.
One of the advantages of using ultransonification to grind explosives is that the energy seen by the particles is easily varied to adapt to the particular grinding and safety requirements. The treatment may be varied by changing the generator power, by changing the particular slurry medium, by changing the slurry temperature, or by changing the frequency. All of these factors are known to affect the intensity of cavitational forces in ultrasonification. Thus, the changing sensitivity of an explosive material due to particle size may be compensated for during the grinding process, if necessary.
The ultrasonic power intensity useful in this invention is expected to vary widely, depending upon the sensitivity of the explosive, the particular slurry medium used, and other factors. It is expected that for most explosives, the most useful range of power intensities is from about 70 to about 120 watts/square cm. of tip area, but more generally greater than 70 watts/square cm.
EXAMPLE
As depicted in FIG. 2, a Heat Systems-Ultrasonics Inc. Sonicator model no W385 ultrasonic generation probe 50 was set up for batch treatment of aqueous slurries of explosive materials. The treatment chamber was a beaker 52 containing the slurry 54, placed in an ice/water bath 56 to keep the bulk slurry temperature below 40 degrees C. The mechanical transformer 58, i.e. horn of the Sonicator ultrasonic generator was placed in the beaker and operated for a given period of time, i.e. 5, 10, 20 or 30 minutes. The tranducer 60 operated through the sonic converter 62 to produce a frequency of 20 KHz and maximum input power of 385 watts. The generator had a pulsating head 64 with a diameter 66 of 0.5 inch and a head area of 0.196 square inches (1.267 square cm.). While the power input was set at maximum for all tests, the output power intensity ranged from about 70 to 120 watts per square centimeter tip area, depending upon the particular slurry medium.
Particulate melamine was first chosen to test the theory, since it has approximately the same hardness as RDX, without being energetic, i.e. explosive. Samples of 10 grams of particulate melamine (26.0% passing a No. 325 U. S. Standard sieve) were each slurried in 30 g of water and subjected to batch sonification at 20 KHz frequency for a period of 5, 10, 20, or 30 minutes. The resulting ground slurries were each evaluated for particle size, in terms of percent of mass which passes the No. 325 U.S. Standard (44 micron) sieve. The results were as follows:
______________________________________PERCENTAGE OF PARTICLE MASS PASSING A NO. 325U.S. SIEVE Sonification Time, MinutesParticulate Material None 5 10 20 30______________________________________Melamine 26.0 60.3 76.3 90.6 97.2RDX 10.8 74.9 79.7 92.3 97.2CPX 72.1 94.3 96.4 98.7 99.3______________________________________
The results are also presented in FIG. 3, and indicate that rapid size reduction was achieved by sonification under these conditions. For example, the rate of grinding the RDX and CPX was much faster than is achieved by recirculation of the slurry in a piping system, as used in the prior art. Detonation was not experienced in any of the tests, although conducted at what are considered to be high power intensities. The rapid rate of particle size reduction at these power intensities indicates that lower power intensities could also be used for explosive grinding, althoush the grinding rate is expected to be somewhat lower. Thus, an explosive material which is ultrasensitive may be ground at a somewhat lower power intensity to avoid any possibility of detonation.
Reference herein to details of the illustrated embodiments is not intended to restrict the scope of the appended claims which themselves recite those features which are regarded as important to the invention.
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The particle size of energetic explosive materials is reduced by slurrying the particulate explosive materials in an inert liquid such as water or an aqueous solution, and subjecting the slurry to intense acoustic cavitation from an ultrasonic generator for a short time. The particulate explosive materials are rapidly ground to a small particle size while minimizing the danger of detonation.
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FIELD OF THE INVENTION
The subject driver performance monitoring system is generally directed to an onboard computer system for operation on a designated host vehicle. More specifically, the vehicle driver performance monitoring system is an onboard computer system which has in place the hardware and software means to sense various vehicle operation parameters, characterize the driving habits of the current driver based on those parameters with respect to various specified determinants, and make available processed information for digital read-out and display.
The quality of a driver's performance in driving the host vehicle is invariably reflected generally in the physical manipulation of that vehicle and particularly in the parametric variations of that vehicle's electrical/mechanical components. Accordingly, the subject vehicle driver performance monitoring system includes a plurality of parametric sensors which measure the physical parameters associated with the host vehicle components to which they are respectively coupled and generate electrical signals indicative of those measured quantities. The data derived from the formulation of these signals is continually processed and stored during operation of the host vehicle such that updated assessments of the driver's performance in light of various pre-specified performance determinants may be computed.
The need for such driver performance assessments, as provided by the subject vehicle driver performance monitoring system, is manifest in several readily apparent applications. First, parents of driving-aged children well recognize the demonstrated tendency of many teenage drivers to operate an automobile in a less than conservative, often reckless, manner. As they cannot accompany their children in a vehicle at all times, and as their children will rarely operate an automobile in a reckless manner in their immediate presence, those parents currently lack the means to monitor their children's driving habits and, in many cases, lack the information to even suspect that their children in fact exercise poor driving habits. The subject vehicle driver performance monitoring system would provide the continually monitored driving performance information which they critically need in order to maintain control over their children's driving habits and thereby preserve the health and safety of not only their own children, but occupants of other automobiles and bystanders on public streets.
Businesses also possess a discernable need for the driving performance assessments provided by the subject vehicle driver performance monitoring system. It is imperative for any business owning employee-operated vehicles to monitor the driving habits of their employees during the operation of those vehicles. The current practice of many such businesses is to visibly mount on their vehicles signs which solicit complaints from anyone observing careless operation of those vehicles. Except when observers occasionally lodge a legitimate complaint in response to these signs, such businesses are relegated to after-the-fact reports of accidents and other driver-responsible occurrences, or incidental observations, to discover the poor driving habits of their employees. This not only compromises public safety, it also heightens for businesses the expenses they must allocate for costs associated with otherwise avoidable accidents and the increased insurance premiums resulting from them. Moreover, the lack of satisfactory means to effectively monitor employee driving habits deprives businesses of an opportunity to improve the driving performance of their employees and, thereby, actually reduce business expenses while promoting public safety.
Another significant application anticipated for the subject vehicle driver performance monitoring system is in the automobile insurance business wherein accurate assessments of driving habits would facilitate accurate and fair allocations of costs. As most automobile insurance companies currently rely primarily on age, sex, and the driving record of the insured individual in estimating the risk of insurance payouts caused by that individual, only marginal estimates of such risks are attained; and unfair assessments of the applicable insurance premium for that individual often result. Reckless though fortunate drivers, who but for the care fortuitously employed by other drivers, have avoided serious automobile accidents are regularly assessed an insurance premium as low as, if not lower than, more careful drivers but unfortuitous drivers who, except for a single unavoidable traffic incident, would have an unblemished driving record. Similarly, careless automobile owners who mistreat their vehicles or push the operation of their vehicles beyond their performance tolerances regularly pay the same, if not lower, premium as do more caring vehicle owners who invest substantial effort to minimize the wear and tear on their vehicles. The accurate assessments of driving performance provided by the subject vehicle driver performance monitoring system would enable automobile insurance companies to remedy these inequities and, as well, reduce their own expenses by appropriately allocating higher costs only among the highest risk drivers. This would enable insurance companies to both attract more careful drivers and encourage safer driving habits even in the most reckless of drivers they already insure.
PRIOR ART
Onboard vehicle computer systems which incorporate means for sensing vehicle component parameters are known in the art. The best prior art known to Applicant includes U.S. Pat. Nos. 5,207,095; 5,034,894; 5,074,144; 4,500,868; 4,933,852; 4,716,458; 4,275,378; 4,093,039; 5,150 609; 4,945,759. Such known systems, however, are directed primarily to performing vehicle diagnostics, assessing vehicle performance, or training an operator to master various facets of vehicle operation. There is no onboard computer system heretofore known which continually monitors the driver performance of a host vehicle as comprehensively as does the subject vehicle driver performance monitoring system.
For instance, U.S. Pat. No. 5,207,095 is directed to an onboard vehicle computer system for use in evaluating an operator's braking technique which employs a plurality of vehicle-mounted sensors. The onboard computer in that system periodically receives and stores the parametric values associated with vehicle braking sensed by the sensors. The data thus generated by that computer is then available to be read later by an instructor who will compare the recorded parametric values to formulate further instructive steps. Unlike the subject vehicle driver performance monitoring system, however, that system does not perform evaluative functions on the data. Any evaluations to be made in light of the raw data are left for the user to make himself or herself. Furthermore, as the vehicle sensor monitoring system there is intended specifically as an instructional tool, monitoring is performed only during those discrete time intervals related to an instructional session. It is not performed in correlation continually with the host vehicle's operation, as is the monitoring in the subject vehicle driver performance monitoring system.
In addition, the intended instructional applications for that system reveal no apparent need to question driver integrity; therefore no driver integrity checking means are therein provided. In the subject vehicle driver performance monitoring system, however, the integrity of the host vehicle driver is an ever-present concern, the compromise of which would wholly undermine the utility of the system. The subject vehicle driver performance monitoring system therefore includes means for recording any attempt to either operate a given system on a vehicle other than the uniquely identified host vehicle for which it is configured or to otherwise tamper with proper system operation.
U.S. Pat. No. 5,034,894 directs itself to a self-diagnosis computer system onboard a motor vehicle wherein a plurality of detectors are mounted on that vehicle's engine to detect any aberrant operating conditions. Although the computer system there performs continual monitoring while the vehicle is in operation, no provision is made for the assessment of driver performance based on any sensed parameters.
Similarly, U.S. Pat. No. 5,074,144 is directed to an onboard vehicle computer system for monitoring vehicle performance. Various transducers for continually monitoring various vehicle parameters are employed in that system; however, comprehensive means for analyzing the measured vehicle parameters to characterize or assess driver performance, per se, are not provided.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram showing the major functional components of the subject driver performance system;
FIG. 2 is a system flow block diagram of the sensor data evaluation and sensor data storage functions in the subject driver performance monitoring system; and,
FIG. 3 is a system flow block diagram of the serial port communications function in the subject driver performance monitoring system.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to FIG. 1, the subject vehicle driver performance monitoring system generally includes a microprocessor module 1, vehicle mounting unit 2, playback mounting unit 3, a plurality of vehicle sensors 40-43, and software to be described in paragraphs to follow for system control, as well as data processing and analysis. Microprocessor module 1 is preferably a self-contained, detachable modular unit which must be coupled to vehicle mounting unit 2 in order for the subject vehicle driver performance monitoring system to be operational. All external interconnections leading to and from microprocessor module 1 shown in the functional flow diagram of FIG. 1, with the exception of that interconnection between microprocessor input/output (I/O) port 22 of microprocessor 20 and playback mounting unit 3, are physically interfaced through the mounting of microprocessor module 1 onto vehicle mounting unit 2. Thus, microprocessor module 1 may be readily detached from vehicle mounting unit 2 and the host vehicle and later re-mounted on vehicle mounting unit 2 prior to host vehicle operation. A detached microprocessor 1 may also be re-mounted either on playback mounting unit 3 or on the vehicle mounting unit 2 of another host vehicle if so desired, as long as the necessary system data reconfiguration reflecting the change is first performed.
Microprocessor module 1 contains microprocessor 20 along with various processing support units which include power supply unit 10, RS232 converter 30, vehicle network converter 31, non-volatile storage device 32, and real time clock 33. Microprocessor 20, which serves as the processing engine for the subject vehicle driver performance monitoring system, comprises CPU 21, microprocessor I/O port 22, serial port 23, internal ROM 24, internal RAM 25, A/D converter 26, and multiplexer 27. Microprocessor 20 is preferably a standard 8-bit microprocessor chip such as a Phillips 8XC562 or other comparable chip commercially available. It incorporates as firmware stored in ROM 24, software for operation of all system components and control of data passage therebetween, as well as software for data processing and evaluation. Driven by this firmware, CPU 21 processes the system-generated parametric data received from vehicle component sensors 40-43 via A/D converter 26 and multiplexer 27.
In certain applications, system data will be available from sources other than the designated vehicle component sensors 40-43. To enable digital communication for the acquisition of parametric system data in such applications, vehicle network converter 31 and RS232 converter 30 are provided to respectively perform the signal conversions necessary to effect digital communication between the serial port 23 of microprocessor 20 and either the vehicle data network resident on the host vehicle or a source having RS232 compatibility.
During the progression of the data processing and evaluation functions performed by microprocessor 20, temporary data storage occurs in RAM 25 internally provided in microprocessor 20. System-generated data, as well as user-provided system configuration data, is stored in a separate non-volatile storage device 32 which, in the preferred embodiment, is a low power RAM, such as the Hitachi HM62256, coupled to the address, data, and control lines of the microprocessor 20 microprocessor BUS. This non-volatile storage device 32 is equipped with a commercially available back-up power and clocking source such as the Dallas semi-conductor DS1216D so that the data contents stored therein may be preserved during those periods when microprocessor module 1 is decoupled from vehicle power or where vehicle power failure occurs. The clocking source is a real time battery-backed clock 33 well known in the art and commercially available which is serially addressed from the microprocessor BUS which time tags all sensor data saved in the non-volatile storage device 32.
Power supply 10 of microprocessor module 1 which is coupled to vehicle power by the mounting of microprocessor module 1 onto vehicle mounting unit 2 makes available the DC supply signals necessary to drive all system components. A switch mode regulator is employed to minimize power consumption and heat dissipation; as an unswitched +5 VDC supply signal is sufficient in driving the microprocessor system while a switched +5 VDC supply signal is preferable in driving the sensors 40-43, signal conditioning units 44, and signal voltage converters 30, 31. Where optional sensors requiring the conventional +12 VDC vehicle power supply signal are used in the system, power supply 10 also filters the vehicle power signal to provide a clean +12 VDC supply. Power supply 10 also includes input and output surge suppressors to reduce the likelihood of damage due to surges that may occur in the vehicle supply voltage.
As already mentioned, microprocessor module 1 must be mounted onto vehicle mounting 2 in order for the vehicle driver performance monitoring system to be operable. Vehicle mounting unit 2 itself may be mounted either directly in the host vehicle's engine or compartment or inside the host vehicle's passenger compartment and is, preferably, a mechanically rigid unit which securely receives and supports microprocessor module 1 while coupling it electrically for operation. The mounting unit 2 includes a plug connector that mates with a matching connector on microprocessor module 1 to concurrently couple power supply 10 to host vehicle power and the lines of multiplexer 27 of microprocessor 20 to the corresponding lines leading to and from the signal conditioners 44 of sensors 40-43.
Also included in the mounting unit 2 is an electronically readable device such as the Dallas semi-conductor DS2224 encoded with a unique identification code (UIC) to designate the given host vehicle. Electrical connections are run between this UIC device 4 and the plug connector of vehicle mounting unit 2 such that when the microprocessor module 1 is mounted to mounting device 2, microprocessor 20 gains serial access to the identification code through its I/O port 22. This connection enables microprocessor 20 to perform system integrity checks as part of each system power-up sequence which insure that the information accumulated for the driver of a designated host vehicle is not erroneously attributed to a driver of a different host vehicle to which the microprocessor module 1 belonging to a designated host vehicle's system is wrongfully or mistakenly removed and mounted.
A plurality of sensors 40-43 are situated in any suitable fashion on various parts of the host vehicle. These sensors include, but are not limited to, ground speed, engine RPM, steering wheel rotation, dual axis tilt, and tri-axis linear and angular acceleration sensors. In the preferred embodiment, host vehicle ground speed is derived from the vehicle's wheel rotation rate measured either with a drive shaft encoder or a tapped link to the vehicle speedometer. The engine RPM is sensed by coupling an inductive coil pick-up device such as a CR magnetics device model 19 to the host vehicle's ignition wire. The host vehicle's steering wheel rotation is measured with a shaft encoder coupled to the vehicle's steering linkage. The host vehicle's lateral tilt is measured with a dual axis tilt sensor such as the Spectron SP5003 preferably mounted at or near the vehicle's inertial center. Finally, the host vehicle's acceleration is preferably measured about each of three orthogonal axes using piezo films such as the AMP ACH-01 films which may be appropriately oriented and applied on suitable surfaces of the vehicle, but are preferably so applied on microprocessor module 1.
Each sensor 40, 41, 42, 43 interfaces with multiplexer 27 of microprocessor 20 through a signal conditioner unit 44 which formats the electrical signal generated by that sensor to bring it within the operating voltage range of microprocessor 20. Each signal conditioner unit 44 includes anti-aliasing filters and gain/offset adjustment means to convert the output voltage range of the sensor to which it is connected to the 0-+5 VDC range of microprocessor 20. As shown, the analog outputs of signal conditioners 44 are fed to multiplexer 27 for the sequential switching thereby to the analog to digital (A/D) converter 26 which then converts each analog sensor signal into a corresponding 8-bit digital signal.
It should be noted that in an alternate embodiment, vehicle component data may be available directly from the host vehicle's internal data network. Sensors 40-43 may, in that case, not be necessary as the vehicle components data to be measured thereby will have already been measured by resident components on the host vehicle. The data available on the vehicle's data network may then be retrieved by microprocessor 20 through its serial port 23 following the necessary signal conversions performed by vehicle network converter 31. Typically, parameters such as vehicle speed and engine RPM will be available in this manner.
The discussion heretofore has described a "black box" system which, for obvious safety reasons on a vehicle, does not provide for a built-in data read-out and display means to which a driver's attention could be easily diverted. Rather, the subject vehicle driver performance monitoring system provides a playback mounting unit 3 preferably co-located with a remote computer, which includes a connector that links to the lines of I/O port 22 of microprocessor 20 of a mounted microprocessor module 1 and mates with a matching connector having a standard serial data link to the co-located remote computer. The subject system also provides for software which, when installed on a remote computer so linked to microprocessor 20, enables a user to perform a variety of menu-driven functions. These functions include means for: reading into and storing on the given remote computer's data storage medium system data from the data base generated in microprocessor module 1; clearing the generated data base of microprocessor module 1; cataloging the system data read into desired file hierarchies on the remote computer data storage medium; reconfiguring the system configuration data base of microprocessor module 1; reading and resetting the system time on microprocessor module 1; performing various analyses on the generated system data read from microprocessor module 1; and displaying or transferring to a printer raw system data and any analysis results.
To examine or evaluate system data, therefore, a user may connect to microprocessor module 1 via I/O port 22 a portable laptop computer brought into the host vehicle for such purpose. Alternatively, a user may detach microprocessor module 1 from vehicle mounting unit 2, remove that module from its host vehicle to a remote computer site, and then mount that module on the playback mounting unit 3 linked at that site to a standard desktop computer for examination and analysis of data thereon.
The software resident on microprocessor module 1 as firmware stored in microprocessor ROM 24 will now be discussed. This software generally performs system control and system data processing functions. The system control function includes means for managing, reversibly transferring, and storing data within the subject vehicle driver performance monitoring system as well as a means for establishing the interfaces necessary for communication between the microprocessor module 1 and other processing or peripheral equipment external thereto. It also includes means for periodically performing system integrity checks to verify, first, that a given host vehicle to which the microprocessor module 1 is operably mounted is indeed the particular host vehicle for which that microprocessor module 1 is specifically configured; and, second, to set a flag where system parametric conditions indicate that the host vehicle to which a microprocessor module 1 is correctly coupled has been operated without the corresponding operation of that microprocessor module 1. This second check prevents the subject driver performance monitoring system from being bypassed covertly by, for instance, making a record of the odometer reading either passed automatically to the system via the host vehicle's resident data network or read manually, then entered on the system through a remote PC interface.
The system data processing software includes means for sequentially reading raw data generated by each of the vehicle sensors 40-43, time tagging and cataloging that data, and performing various analytical functions on the system data so accumulated. In performing these functions, the system data processing software accesses the system configuration data base to ultimately achieve characterizations of driver performance with respect to at least one or more predetermined driver performance determinants entered in that configuration data base essentially in the form of sensor data weighting coefficients.
Referring now to FIGS. 2 and 3, the functional progression of the subject vehicle driver performance monitoring system firmware is illustratively depicted in three functional loops: loop A, loop B, and loop C. Loop A which depicts the progression of the system data evaluation function and loop B which depicts the progression of the system data storage function are executed in a synchronous manner in that loop B is executed each processing frame when a peak value is available out of peak filter 140 of loop A. Loop C, illustrated in FIG. 3, which depicts the progression of highest level system control function, is performed asynchronously in relation to loops A and B.
Upon each power-up of the subject vehicle driver performance monitoring system, the real time clock 33, the host vehicle's unique identification code device 4, and the host vehicle's odometer (either through a corresponding sensor or from the vehicle data network) are read for their current values, as indicated in blocks 90-92. A time record comprising current power-up time, time of last system shutdown, host vehicle unique identification code, host vehicle odometer reading at last system shutdown, host vehicle odometer reading at current power-up, and total distance travelled during last operation of the system is formulated and entered on the non-volatile storage medium 32 to update the data base of time records stored thereon. If this time data base is full the oldest time record is deleted as the current time record is added. Prior to deletion of the oldest time record, however, that part of the record indicating total distance travelled during the preceding system operation is noted, and the value is added onto a special total distance travelled overflow record saved as part of the time data base. The preceding time data record data base update functions occur as block 93.
The information contained in the current time record is used to perform initial processing steps prior to the execution of program loops A, B, and C. The pair of time values, each preferably consisting of month, date, year, hour, minute, and second indications, are compared to log the times during which the microprocessor module i was decoupled from host vehicle power. The host vehicle unique identification code is examined to select the correct system configuration data base for the given host vehicle if more than one system configuration data base have been stored in the given microprocessor module 1; and, conversely, to associate the measured sensor data records with the correct host vehicle later during performance evaluation. The odometer readings and the total distance travelled during the preceding system operation are used in making a present determination as to whether or not the given host vehicle was operated without the corresponding operation of its driver performance monitoring system. Immediately following these initial processing steps, execution of program loops A, B and C is begun.
In program loop A, measurement data originating from each of the vehicle sensors 40, 41, 42, 43 is continually read in sequence, as shown in blocks 100,110, in order that a driving performance measure pertaining to the measured sensor data values be computed in block 120 for each set of sensor data reads. The measured data originating from each of the vehicle component sensors 40, 41, 42, 43 represents a coefficient in the computation of this driving performance measure. Where one or more of the expected sensors is not incorporated into the host vehicle or temporarily not functioning, a default coefficient, or sensor value, stored in the system configuration data base is used in place of that missing data when the computation is performed. In block 130, the distance travelled by the host vehicle during the immediately preceding time increment is computed by integrating the host vehicle speed over that increment. This distance measure is then combined with the total distance maintained since system power-up to determine for the current driving performance measure a total distance travelled parameter.
A temporary sensor record comprising the measured sensor data values, the computed driving performance measure, the updated total distance travelled, and the current time is stored in scratch memory as soon as each value is available. This iteration is then repeated over a predetermined number of times over a frame lasting a predetermined number of seconds, N. At the conclusion of each frame, the accumulation of temporary sensor records resulting in scratch memory is sorted to select the temporary resulting sensor record having the highest driving performance measure. That sensor record is then extracted in block 140 by the peak filter, and the next frame of loop A executions is begun. As higher driving performance measures indicate qualitatively worse driving habits, this process notes and passes for storage into the sensor data base in loop B the worst driver performance during the immediately preceding processing frame.
As shown in FIG. 2, loop B executes only once every N second processing frame when the temporary sensor record having the highest driving performance measure is extracted by the peak filter in loop A. Loop B updates the sensor data base maintained in non-volatile storage medium 32 of microprocessor module 1 if sufficient storage space is available, and insures that only the sensor records having the highest driving performance measures are retained. therein if sufficient storage space for all sensor records is not available. The progression of blocks for the case when the non-volatile storage medium 32 is not full occurs as shown in blocks 200, 240, and 250. Where non-volatile storage medium 32 is full, the sensor data record having the lowest driving performance measure is selected from the existing sensor data base in block 210. In block 220, the driving performance measure in the sensor data record so selected in block 210 is then compared with the driving performance measure in the sensor data record currently selected by the peak filter in block 140 of loop A. If the driving performance measure in the currently extracted sensor data record does not exceed the driving performance measure in the old sensor data record selected from the existing sensor data base, execution of loop B immediately proceeds to block 250 where the current time and odometer settings are read and recorded on the non-volatile storage medium 32; then execution is halted until the next frame. If, however, the driving performance measure in the currently extracted sensor data record exceeds the driving performance measure in the old sensor data record, the old sensor data record is replaced with the current sensor data record as shown in block 230. Thereafter, the current time and odometer settings are read and recorded as described in block 250 along with the total distance travelled since the last system power-up.
Referring now to FIG. 3, program loop C, which executes independent of loops A and B, is shown. During each loop, the serial port buffer 23 of microprocessor 20 is checked in block 300 for any remotely-generated data read commands. If no such remote command is present, execution of loop C is halted until after a predetermined time has elapsed, and a check of the serial port 23 buffer is again initiated. If a remotely-generated command either requesting transfer of data from the sensor or time data bases, or requesting a clear of the sensor or time data bases is present, such request is complied with and execution of loop C is halted, as shown in FIGS. 310-380. If, as shown in block 390, a remote command requesting system reconfiguration is present, the new system configuration parameters passed with that command are read, and the non-volatile storage medium 32 of microprocessor module 1 is accordingly updated, as shown in blocks 390-400. Similarly, if a remote command to either send the current time in the real time clock 33 or a request to update that time is received, the appropriate compliance procedures shown in blocks 420 and 440 are followed. After execution of each compliance procedure, loop C halts until a check of the serial port buffer 23 is re-initiated. Any other valid commands remotely passed to serial port 23 may be similarly detected and complied with in loop C.
Although this invention has been described in connection with specific forms,and embodiments thereof, it will be appreciated that various modifications other than those discussed above may be resorted to without departing from the spirit or scope of the invention. For example, equivalent elements may be substituted for those specifically shown and described, certain features may be used independently of other features, and in certain cases, particular combination of system control or system data processing steps may be reversed or interposed, all without departing from the spirit or scope of the invention as defined in the appended claims.
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A vehicle driver performance monitoring system is provided. A plurality of vehicle component sensors (40-43) suitably mounted to a host vehicle measure a plurality of vehicle component parameters indicative of a host vehicle's driver performance. A microprocessor module (1) detachably coupled to the vehicle mounting unit (2) affixed to and uniquely designated for a given host vehicle poles each vehicle sensor (40-43) of that host vehicle to read, process, and store the vehicle operation data generated thereby. A playback mounting unit (3) is provided to facilitate the connection of a remote computer to the host vehicle's microprocessor module (1) in order to establish digital communication whereby the vehicle operation data and the analysis results processed therein are retrieved and displayed for a user.
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This application claims the benefit of priority to U.S. Provisional Patent Application Ser. No. 61/921,213 filed Dec. 27, 2013, which is incorporated by reference in its entirety.
FIELD OF INVENTION
This invention relates to securing openings, and in particular to systems, devices, apparatus, kits and methods of attaching transparent plastic panels over door and window openings of vacant and/or damaged buildings and houses, with triangular flange brackets which are attached to both the panels and adjacent frames and casings about the openings.
BACKGROUND AND PRIOR ART
In the last decade, there has been an increase in the number of buildings and houses, where the property owner has left the property due to property owners defaulting on loans that exceed the actual value of the property, and/or leaving properties that have been damaged by storms, or vandalism, and the like. As such, lenders and mortgage companies have the need for property preservation to secure the empty and vacant buildings and houses.
Vacant structures occasionally have broken windows, which can be an attractive nuisance for vagrants, criminals and children and can result in thefts and destruction of interiors of the structures, as well as be unsafe and dangerous to persons entering the property
Boarding up openings with plywood and traditional shutters, can be both expensive, and time consuming. Additionally, using fasteners, such as nails, screws, and/or bolts to directly attach boards and shutters can cause further damage to the property.
Additionally, boards and shutters are generally opaque and do not allow light therethrough. As such, the interiors of the structures are darkened which can result in further problems by having darkened interiors at all times.
Furthermore, the use of boards and shutters gives an immediate indication to a passerby that the property is vacant, which further attracts vagrants, criminals and children that can cause undesirable problems such as damage to the property.
Still furthermore, the appearance of boarded up windows and opaque shutters are both unsightly and can lower the property values for the buildings and houses.
As such, there exists a need to allow for simple and easy securing of the buildings and houses for property preservation. Additionally, there is a need for securing openings to the property with panels that are transparent and let light into the structures, and can give the appearance of the property not being vacant.
Thus, the need exists for solutions to the above problems with the prior art.
SUMMARY OF THE INVENTION
A primary objective of the present invention is to provide systems, devices, apparatus, kits and methods of attaching transparent plastic panels over door and window openings of vacant and/or damaged buildings and houses, with flange brackets which are attached to both the panels and adjacent frames about the openings.
A secondary objective of the present invention is to provide systems, devices, apparatus, kits and methods for securing openings such as windows and doors of vacant and/or damaged buildings and houses that can be easily attached without causing permanent damage to the openings.
A third objective of the present invention is to provide systems, devices, apparatus, kits and methods for securing openings such as windows and doors of vacant and/or damaged buildings and houses that are easily and inexpensively attached to the openings.
A fourth objective of the present invention is to provide systems, devices, apparatus, kits and methods for securing openings such as windows and doors of vacant and/or damaged buildings and housings, using transparent panels to allow light inside.
A fifth objective of the present invention is to provide systems, devices, apparatus, kits and methods for securing openings such as windows and doors of vacant and/or damaged buildings and houses, that give the appearance of the openings not being vacant nor boarded up or closed with shutters.
A sixth objective of the present invention is to provide systems, devices, apparatus, kits and methods for securing openings such as windows and doors of vacant and/or damaged buildings and houses, that are not unsightly and do not result in lowering of the property value of the buildings and houses.
A securing system for covering openings to buildings and housings, can include a rigid plastic panel sized to cover at least one exterior opening through a frame casing to a structure, at least one pair of rigid flange brackets sized to cover a lower left corner and a lower right corner of the plastic panel, and fasteners for attaching the plastic panel to the exterior of the structure opening so that the plastic panel is on an exterior side of the structure opening and the rigid flange brackets are on an interior side of the structure opening.
The plastic panel can be selected from at least one of a solid transparent acrylic material, a solid transparent resinous material, or a transparent polycarbonate material.
The rigid flange brackets can include a generally triangular shape. Each of the rigid flange brackets can include a long generally flat vertical side perpendicular to a shorter generally flat base, a flat top, and angled side which angles from the flat top angling downward at an angle to second flat vertical side which is shorter than the long flat side. The long flat side can have a length of approximately 5″ to approximately 7″, and the base can have a length of approximately 5″ to approximately 7″, the second side can have a length of approximately 2″ to approximately 3″, the flat top can have a length of approximately 2″ to approximately 3″, and an angled side of approximately 4 and ½″ to approximately 5 and ½″. Each rigid flange bracket can include a central through-hole of approximately ½″ diameter. Each rigid flange bracket can have a thickness of approximately ¼″ to approximately ⅛″ to approximately 3/16″.
The rigid flange brackets can include materials selected from stainless steel, galvanized metal and aluminum. Each of the rigid flange brackets can be formed from transparent rigid plastic material identical to the transparent rigid plastic panel.
The structure opening can include a window with glass attached.
A method of securing openings on structures, can include the steps of sizing a rigid plastic panel to fit over an opening to a structure, providing at least a pair of rigid flange brackets, positioning the rigid transparent plastic panel over the exterior of the structure opening, positioning one of the rigid flange brackets to overlap over a lower left corner portion of an interior to the structure opening and over a portion of a lower left corner of a frame casing about the structure opening, positioning another one of the rigid flange brackets to overlap over a lower right corner portion of an interior to the structure opening and over a portion of a lower right corner of a frame casing about the structure opening, attaching the rigid flange brackets to the sized rigid plastic panel with fasteners, so that the structure opening is securely covered and protected by the rigid plastic panel.
A kit for covering openings to buildings and housings, can include a rigid plastic panel sized to cover at least one exterior opening through a frame casing to a structure, at least one pair of rigid generally triangular flange brackets sized to cover a lower left corner and a lower right corner of the plastic panel, and fasteners for attaching the plastic panel to the exterior of the structure opening so that the plastic panel is on an exterior side of the structure opening and the rigid flange brackets are on an interior side of the structure opening.
Further objects and advantages of this invention will be apparent from the following detailed description of the presently preferred embodiments which are illustrated schematically in the accompanying drawings.
BRIEF DESCRIPTION OF THE FIGURES
FIG. 1 is an exploded view of the novel triangular flanges with fasteners and plastic sheet for use with protecting window openings to a building or house.
FIG. 2 is an enlarged front view of one the novel triangular flanges of FIG. 1 .
FIG. 3 is a rear view of the triangular flange of FIG. 2 .
FIG. 4 is a side view of the triangular flange of FIG. 2 along arrow 4 X.
FIG. 5 is a partial perspective interior view of a window opening to a building or house with the triangular flanges on the interior lower corners over the window casing with the sheet panel on the exterior with the fasteners attaching the flanges to the sheet panel.
FIG. 6 is an interior view of the window opening with flanges and panel shown in FIG. 5 .
FIG. 7 is an exterior view of the window opening with flanges and panel shown in FIG. 5 .
FIG. 8 is a flowchart of the installation steps to install a plastic panel over an opening shown in FIGS. 5-7 , using the novel triangular flange brackets of FIGS. 1-3 .
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Before explaining the disclosed embodiments of the present invention in detail it is to be understood that the invention is not limited in its applications to the details of the particular arrangements shown since the invention is capable of other embodiments. Also, the terminology used herein is for the purpose of description and not of limitation.
In the Summary above and in the Detailed Description of Preferred Embodiments and in the accompanying drawings, reference is made to particular features (including method steps) of the invention. It is to be understood that the disclosure of the invention in this specification includes all possible combinations of such particular features. For example, where a particular feature is disclosed in the context of a particular aspect or embodiment of the invention, that feature can also be used, to the extent possible, in combination with and/or in the context of other particular aspects and embodiments of the invention, and in the invention generally.
In this section, some embodiments of the invention will be described more fully with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout, and prime notation is used to indicate similar elements in alternative embodiments.
A list of components will now be described.
10 fasteners, such as bolts and screws 11 enlarged head of fastener(s) 14 threads 16 washer(s) 18 nut(s) 20 plastic sheet/panel 100 triangular flange(s)/bracket(s) 110 long side 120 short side 130 base 142 flat top 144 angled edge 150 through-hole 210 interior window frame/casing 220 exterior window opening 225 . existing glass in window opening
FIG. 1 is an exploded view of the novel triangular flanges/brackets 100 with fasteners 10 and plastic panel/sheet 20 for use with protecting window openings to a building or house. FIG. 2 is an enlarged front view of one the novel triangular flanges/brackets 100 of FIG. 1 . FIG. 3 is a rear view of the triangular flange/bracket 100 of FIG. 2 . FIG. 4 is a side view of the triangular flange/bracket 100 of FIG. 2 along arrow 4 X.
Referring to FIGS. 1-4 , a kit can include a pair of fasteners 10 , can be bolts with enlarged heads 12 , threads 14 , washer(s) 16 and nut(s), a pair of triangular flanges/brackets 100 , and a rigid plastic sheet/panel 20 .
The panel/sheet 20 can be formed from a rigid material, such as polycarbonate. The panel/sheet 20 can be formed from a rigid transparent plastic, such as but not limited to a solid transparent acrylic material, a solid transparent resinous material, or a transparent polycarbonate material, such as those sold under the trade names of LEXAN®, PLEXIGLASS® and the like, can be used.
Each of the novel triangular flanges/brackets 100 can be generally right angled with long sides 110 of approximately 5″ to approximately 7″, and a base 130 having a length of approximately 5″ to approximately 7″, a short side 120 length of approximately 2″ to approximately 3″, a flat top 142 length of approximately 2″ to approximately 3″, and an angled side 144 of approximately 4 and ½″ to approximately 5 and ½″(an angle of approximately 45 degrees) and a central through-hole 150 of approximately ½″ diameter. Each of the flanges/brackets 100 can have a thickness of approximately ¼″ to approximately ⅛″ to approximately 3/16″.
The term approximately can include +/− ten percent of the value referenced. Other dimensions can be sized as needed.
The flanges/brackets 100 can be formed from rigid metal materials, such as but not limited to plastic, and metal such as but not limited to stainless steel, galvanized metal, aluminum, and the like. Additionally, the flange brackets can be formed from transparent material such as the same material used for the transparent rigid panels. The flange brackets can be solid materials, or honeycomb inside or hollow.
FIG. 5 is a partial perspective interior view of a window opening 220 to a building or house with the triangular flanges/brackets 100 on the interior lower corners over the window casing 210 with the sheet panel 20 on the exterior with the fasteners 10 attaching the flanges/brackets 100 to the sheet panel 20 . FIG. 6 is an interior view of the window opening 220 with flanges/brackets 100 and panel 20 shown in FIG. 5 . FIG. 7 is an exterior view of the window opening 220 with flanges/brackets 100 and panel 20 shown in FIG. 5 .
FIG. 8 is a flowchart of the installation steps to install a plastic panel over an opening shown in FIGS. 5-7 , using the novel triangular flange brackets of FIGS. 1-3 .
Referring to FIGS. 1-8 , an opening 220 , such as a window opening in a building structure or house structure having broken glass 225 , needs to be secured. The novel invention can install rigid transparent plastic panels 20 over the exterior of window openings 220 using the novel triangular flanges/brackets 100 .
The installer measures the window opening 220 to determine the size of the rigid transparent plastic panel 20 that is needed. The correct size can be cut to cover part or the entire glass area 225 of the window opening 220 . Next, the installer places the cut panel 20 over the exterior of the glass area 225 of the window opening 220 .
Next, the installer places the novel triangular flanges/brackets 100 on the bottom left and bottom right of the interior of the window opening, so that the triangular brackets overlap the frame or casing 210 of the window opening 220 .
Next, the installer can drill holes 150 using a drill through the triangular flanges/brackets 100 and through the transparent plastic panels 20 . A hole size 150 can be approximately ½ inch. Alternatively, the flanges/brackets 100 can have existing hole(s) therethrough. Next, fasteners 10 such as bolts with nuts and washers can be used to secure and sandwich portions of the frame/casing 210 of the window by the exterior positioned transparent plastic panel 20 using the triangular flanges/brackets 100 on the inside of the window opening 220 . For example, the heads 12 of the bolts 10 can be on the exterior of the window opening 220 and the nuts 18 on the inside, where the nuts 18 are screwable and attach to the threads 14 of the fasteners 10 . Alternatively, the bolt heads 12 can be on the inside and the nuts 18 on the outside. A locking washer(s) 16 can also be used with the fasteners 10 . Additionally, other types of fasteners 10 can be used, such as but not limited to carriage bolts, and screws, and the like.
In the preferred embodiment, other generic types of fasteners 10 , such as but not limited to bolts, screws and the like, can also be used on the top edge(s) of the transparent plastic panel 20 to attach the panel to the frame/casing 210 , without using the novel triangular flanges/brackets 100 . Additionally, the novel triangular flanges/brackets 100 can also be placed over the top right and top left upper casings 210 of the window opening 220 fastened to the transparent plastic panels 20 and similarly attached. The transparent rigid plastic panels 20 can be easily removed from the openings by reversing the installation steps referenced above.
The novel triangular flanges/brackets 100 are an extension to the inside from a corner(s) (flange) casing 210 of an opening 220 to a window or other object. The flange/bracket 100 , of suitable size, shape, material and strength, placed over the corners of something to be covered, is intended to accept a threaded or unthreaded fastener in order to secure a cover over an opening. The novel triangular flanges/brackets 100 can utilize holes 150 of suitable size, in line with holes drilled through the covering, to insert the above mentioned fastener.
The fastener will be passed through the primary surface, the covering, to be secured. A hole of suitable size is drilled through the primary surface to allow the fastener to pass through. A suitable stop is on, or must be placed on, the fastener to prevent it from going through the primary surface. The number of holes drilled, the position of the holes and the number of the novel triangular flange brackets used depends on the size of the opening to be covered and the type of covering material used. If the novel triangular flange brackets material is the same as the covering material, the flange is virtually invisible. This is especially true if clear material is used.
Although a triangular shape is described, the novel flanges/brackets 100 can have other shapes such as but not limited to other geometrical shapes and the like. A flat or other shaped object placed inside the opening where there is a stopping point such as a window with a frame/casing around glass. The object can be a large washer, and have sufficient strength and size for a hole to be drilled therethrough to accept the threaded end of a bolt or screw. Washers and/or nuts can also be used to tighten and secure the outside covering against the flange brackets, thereby making the opposite sides covering virtually immovable except by loosening the nuts from the flange side. The novel flanges/brackets can be made from metal as described above or from the same material as the transparent rigid plastic panels.
Although the openings described in the preferred embodiment in relation to the Figures show window openings, the invention can be used with other openings, such as but not limited to openings for doors and the like.
While the invention has been described, disclosed, illustrated and shown in various terms of certain embodiments or modifications which it has presumed in practice, the scope of the invention is not intended to be, nor should it be deemed to be, limited thereby and such other modifications or embodiments as may be suggested by the teachings herein are particularly reserved especially as they fall within the breadth and scope of the claims here appended.
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Systems, devices, apparatus, kits and methods of attaching transparent rigid plastic panels over door and window openings of vacant and/or damaged buildings and houses, that can include generally triangular flange brackets which are attached to both the panels and both sides of the openings.
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TECHNICAL FIELD
[0001] The invention relates generally to automotive displays and, more particularly, to Head-Up-Displays (HUD) that provide enhanced driving safety.
BACKGROUND ART
[0002] Head-Up-Display (HUD) systems enable drivers to view crucial information without the need to look away from the road. Hence HUD systems have become an increasingly important component for automotive use to enhance road safety.
[0003] Augmented Reality (AR), provides a three-dimensional (3D) viewing experience. A number of technologies have been developed to provide 3D AR, the most relevant of which are as follows:
[0004] U.S. Pat. No. 8,521,411 B2 (Grabowski, Aug. 27, 2013) describes a HUD system that allows a continuous depth volumetric image by rapid mechanical scanning of a lens to re-image a laser beam into floating space. “Opt. Express 14, 12760-12769 (2006)” discloses a method of showing volumetric 3D images with a rapidly rotating mirror scanner to produce multiple slices of inclined images. These mechanical systems suffer from mechanical wear over time and may easily suffer from shock damage if they are not mechanically isolated from the vehicle. Further, the former system would only provide a cable image and hence can only display very limited information to the driver.
[0005] US20040164927A1 (Suyama, Aug. 26, 2004) describes a system where a liquid crystal Fresnel lens with a rapidly variable focal length is used to re-image a display panel to produce a volumetric image. The lens used for this system requires a large variation in power and a fast switching speed. For the system to work, the lens would either need to be very thick, which would compromise its switching speed, or have very small Fresnel zone size, which would compromise its image quality. For the lens to switch fast enough to display large depth variation volumetric images, a special type of “dual-frequency” liquid crystals will be required. This type of liquid crystal has not yet been utilized in mass display products, may not necessarily meet automotive standards, and may be expensive to be used in large volume production.
[0006] JP2004168230A describes an automotive HUD system that uses multiple pixelated liquid crystal panels and an ordinary backlight unit to display images at different depths. Such a system will have a very low optical efficiency, meaning the system will consume significant power to achieve high brightness required by automotive displays. The system would also have a limited display contrast, which is a known limitation of liquid crystal display panels with ordinary backlights.
[0007] U.S. Pat. No. 5,764,317 (Sadovnik, Jun. 9, 1988) and U.S. Pat. No. 6,100,862 (Sullivan, Aug. 8, 2000) describe systems that produce volumetric images by using a projector to sequentially project a different image onto an array of switchable screens.
[0008] However, these systems are only capable of displaying images at discrete depth planes. Since the screens can never be fully transparent, haze will become noticeable if the number of screens is increased in attempt to display a pseudo-continuous volumetric image.
[0009] U.S. Pat. No. 4,670,744 (Buzak, Jun. 2, 1987) describes a system that uses a stack of cholesteric liquid crystal as switchable mirrors to change the optical distance between a display panel and the observer. The switchable reflectors are highly dependent on wavelength and angle of the incident light, making it unsuitable for full-color displays.
[0010] Currently there is no augmented reality technology that can achieve low haze, can be manufactured at a relatively low cost, and provide continuous volume augmented reality that uses readily-mass-manufacturable materials that fit automotive performance and safety standards.
SUMMARY OF INVENTION
[0011] The use of three dimensional augmented reality (AR) technologies would allow information being displayed to be integrated into the background traffic. An apparatus in accordance with the present invention relates to a Head-Up-Display (HUD) system suitable for automotive use and augmented reality applications.
[0012] The solution aims to solve one or more problems in the prior art, such as haze, switching speed, color performance, optical efficiency, cost to manufacture, the need for the system's materials' performance to fit automotive requirements, and the need for the system's image quality and safety to automotive standard.
[0013] According to one aspect of the invention, a head-up-display (HUD) system includes: at least one scanning laser projector operative to generate laser light; a stacked array of multiple-switchable screens arranged relative to the projector to receive laser light generated by the projector, each screen of the stacked array of multiple-switchable screens spaced apart from one another and operative to switch between a transparent state and a diffusive state; and a controller operatively coupled to the stacked array of multiple-switchable screens, the controller configured to time sequentially switch each screen of the array from a transparent state to a diffusive state, wherein only one screen is switched to the diffusive state at a given time. An output of the projector is arranged at an angle or a distance from imaging optics succeeding the array of screens to prevent a specular beam emitted by the at least one scanning laser projector from intercepting the imaging optics succeeding the array of screens when all screens are in the transparent state.
[0014] According to another aspect of the invention, a head-up-display (HUD) system includes: a stacked array of screens, each screen of the stacked array screens spaced apart from one another and comprising transparent display panels including pixels capable of providing full image resolution; and a controller operatively coupled to the stacked array of screens, the controller configured to time sequentially display an image on each screen of the array.
[0015] According to another aspect of the invention, a head-u-display includes at least one scanning laser projector operative to generate laser light; a stacked array of multiple-switchable screens arranged relative to the projector to receive laser light generated by the projector, each screen of the stacked array of multiple-switchable screens spaced apart from one another and operative to switch between a transparent state and a diffusive state; a first variable power lens arranged relative to the stacked array of multiple-switchable of screens to receive an image from the stacked array of multiple-switchable screens, the first variable power lens having a variable focal length; and a controller operatively coupled to the stacked array of multiple-switchable screens, the controller configured to time sequentially switch each screen of the array from a transparent state to a diffusive state, wherein only one screen is switched to the diffusive state at a given time.
[0016] To the accomplishment of the foregoing and related ends, the invention, then, comprises the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative embodiments of the invention. These embodiments are indicative, however, of but a few of the various ways in which the principles of the invention may be employed. Other objects, advantages and novel features of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the drawings.
BRIEF DESCRIPTION OF DRAWINGS
[0017] In the annexed drawings, like references indicate like parts or features:
[0018] FIG. 1 is a schematic diagram of an exemplary system in accordance with an embodiment of the invention.
[0019] FIG. 2 is a schematic diagram illustrating a position of a laser beam waist within/near a stack of LC screens.
[0020] FIG. 3 is a schematic diagram illustrating detailed structure of an exemplary variable power lens.
[0021] FIG. 4 is an electronic signal diagram for operating an apparatus in accordance with the invention.
[0022] FIGS. 5 a and 5 b are schematic diagrams showing a virtual image formed by an LC lens.
[0023] FIGS. 6 a and 6 b are schematic diagrams illustrating an optical path of a specular laser coming directly from a projector in possible instances where none of the screens are fully diffusive.
[0024] FIG. 7 is a schematic diagram illustrating another embodiment of an apparatus in accordance with the invention, the apparatus not having a variable power lens. Also shown in FIG. 7 is the optical path of the specular laser emitted by the projector.
[0025] FIGS. 8 a and 8 b are schematic diagrams illustrating an apparatus in accordance with another embodiment of the invention, where the switchable projector screen is pixelated for low temperature operation
[0026] FIG. 9 is a schematic diagram showing advantages of a hybrid spatial-temporal multiplexed system.
[0027] FIG. 10 is a schematic diagram illustrating an apparatus in accordance with another embodiment of the invention with backscattering geometry that eliminates beam blocks.
[0028] FIG. 11 is a schematic diagram illustrating an apparatus in accordance with another embodiment of the invention, where the laser beam is blocked.
[0029] FIG. 12 is a schematic diagram illustrating an apparatus in accordance with another embodiment of the invention, where the variable power lens, instead of having a continuously variable focal length, has multiple discrete focal lengths that can be refocused to. This creates a combinatorial number of possible positions where the virtual image can be displayed.
[0030] FIG. 13 is a schematic diagram illustrating an apparatus in accordance with another embodiment of the invention, the apparatus using multiple transparent LCDs/OLED instead of switchable scattering screens.
[0031] FIG. 14 is a schematic diagram illustrating an apparatus in accordance with another embodiment of the invention, the apparatus using multiple projectors, where each projector projects different images onto one or more switchable screens.
[0032] FIG. 15 is a schematic diagram illustrating an apparatus in accordance with another embodiment of the invention, the system using an interference filter to attenuate a specular laser beam.
[0033] FIG. 16 a illustrates a luminance profile of a PDLC screen in a scattering state.
[0034] FIG. 16 b illustrates a transmission profile of an interference filter at laser wavelength.
DESCRIPTION OF REFERENCE NUMERALS
[0000]
11 : Scanning Laser Projector according to the first embodiment
12 : Lens according to the first embodiment
13 : PDLC screens according to the first embodiment
13 a - d : PDLC screens at different positions.
14 : Mirrors
15 : Liquid crystal lens according to the first embodiment
15 a : Liquid crystal filling
15 b : Transparent polymer
15 c : Indium Tin Oxide
15 d : Substrate of LC lens cell
15 e : Polarizer
16 : Imaging lens
17 : Combiner of the HUD system
18 : Driver/Observer
19 : Laser beam block
20 : Volume where the continuous sets of virtual images can be created by the screens 13 a - 13 d and the LC lens 15 .
21 : Virtual image according to the first embodiment
22 : Instantaneous cross section of laser beam according to the first embodiment.
a: uncollimated beam directly from the projector
b: collimated laser beam with beam waist focus to a position within the stack of PDLC screens.
23 : Electronics for the LC lens according to the first embodiment
24 : PDLC driver according to the first embodiment
25 : Graphics signal sent to the projector
26 : Synchronization Unit according to the first embodiment
30 a - d : Pixelated PDLC screens according to the third embodiment
31 : Lower part of the virtual image according to the third embodiment
32 : Upper part of the virtual image according to the third embodiment
40 : PSCT screens used in backscattering geometry according to the forth embodiment
41 : Partially transparent mirror according to the fifth embodiment
50 : Polarization preserving switchable screens according to the fifth embodiment
51 : Absorbing Polarizer according to the fifth embodiment
60 : A variable power lens capable of refocusing to a discrete number of focal lengths according to the sixth embodiment.
70 a - d : An array of transparent display panels according to the seventh embodiment
80 a - c : Multiple projectors, where each of them may project a different image onto one or more screens according to the eighth embodiment.
81 a - d : PDLC screens according to the eighth embodiment.
90 : Interference filters according to the ninth embodiment.
91 : Scattering profile of PDLC screens according to the ninth embodiment.
92 : Transmission profile of interference filter at laser wavelength according to the ninth embodiment.
93 : PDLC screen in scattering state.
100 : Beam waist of laser according to the first embodiment.
101 : Rayleigh length of laser according to the first embodiment.
102 : Distance between one of the virtual images within the continuously possible set of images 20 and the driver 18 .
103 : Distance between virtual image 21 and the driver 18 .
104 : Distance between virtual image 31 and the driver 18 .
105 : Distance between virtual image 32 and the driver 18 .
106 : Eye-to-eye distance of an ordinary driver
107 a - c : The various possible focal lengths of the lens 60
108 : Optical axis of the imaging optics following the switchable screens such as 15 , 16 , and/or 17
109 : Offset distance of the projector from the optical axis 108
110 : Offset angle of the projector from the optical axis 108
111 : Specular laser beam paths in the case where all switchable screens are transparent.
DETAILED DESCRIPTION OF INVENTION
[0086] An apparatus in accordance with the present invention can include a laser projector, a stacked array of electrically switchable screens, and a variable power lens. A geometry between the components of the apparatus can be arranged such that an exit pupil of the laser projector will never be visible to the driver even when all electrically switchable screens are simultaneously switched transparent to the transparent state.
[0087] The laser projector can be, for example, a laser Micro-Electro-Mechanical Systems (MEMS) scanning projector where the projected image has a large depth of focus and does not require precise focusing. The projector projects an image onto a stack of several switchable diffusing screens, which can be re-imaged by a variable focal lens and other fixed optics to produce a virtual image that appears to be floating in real space at a continuously variable distance from the driver.
[0088] Each of the screens in the system is capable of independently switching between a transparent and a diffusive state via an applied voltage. In order to reduce Fresnel reflections from the surface of the screens, the screens can be glued to refractive index matching material blocks or the screens' surface may be anti-reflection coated. Depending on the availability, cost, image quality and switching speed requirements, the screens can be made from materials in the known arts, such as Polymer Dispersed Liquid Crystal (PDLC), Polymer Network Liquid Crystal (PNLC), Polymer Stabilized Cholesteric Texture (PSCT), or holographic switchable diffusers.
[0089] The variable power lens can have a continuously variable dioptre power tuneable with electrical signals. The lens can be made of, for example, diffractive, surface refractive, gradient refractive, or reflective Fresnel lens. The lens can be immersed in nematic liquid crystals, PDLC with sub-wavelength sized domains, blue phase liquid crystal, or other known methods of electric-tuneable optical path thickness for light polarized in one or more directions. Alternatively, other known types of variable power lenses, including mechanical focusing lenses, mechanical mirrors, electro-wetting lens, and liquid lenses can also be used.
[0090] During operation, each screen can be switched to a diffusive state time sequentially, and the projector forms a different image on the diffused screen. This is re-imaged by a variable focus lens and other subsequent optics such as a refractive lens and a partially transparent combiner mirror, resulting in a virtual image some distance away from the driver.
[0091] The projector's image frame is synchronized with the screens' sequence as well as the power of the variable lens such that the system's operation allows a different image to be displayed at a continuous choice of depths.
[0092] Because the virtual image is formed by a single optical system, it exhibits all depth cues such as focus, binocular convergence, and motion parallax, making it comfortable for long term viewing. Continuously variable virtual image depth in the system allows the virtual image to be seamlessly integrated into the traffic scene.
[0093] The range of positions that can be formed by the full HUD system becomes a combinatorial set of images that can be formed from each screen by the variable power lens. Since switching speed of liquid crystal cells are inversely proportional to the square of the cell gap thickness, adding extra switchable screens into the system would provide quadratic improvement to system's switching speed while still providing the full depth range of virtual images.
[0094] A first embodiment of a display in accordance with the invention is shown in FIGS. 1-6 and described in the following paragraphs. The illustrated embodiment is a head-up-display system where the overall optical components are shown in FIG. 1 . The display includes a laser scanning projector 11 followed by a lens 12 and a stacked array of multiple-switchable screens 13 . The laser scanning projector 11 can be a Micro-ElectroMechanical Systems (MEMS) which allows a high resolution image to be displayed over a large depth of focus. A controller 10 is operatively coupled to the projector 11 and the stacked array of screens 13 and configured to operate the HUD system as described herein.
[0095] Although the lens 12 in this embodiment is illustrated as a single element lens, it can also include several groups or elements. The stack of screens 13 are capable of being independently switched by the controller 10 between a transparent and a diffusive state by applying an electrical signal to each of them. The material used for the screen may be Polymer Dispersed Liquid Crystal (PDLC). The screen can also be made of other known materials that are capable of being used as switchable diffusers such as Polymer Stabilized Cholesteric Texture (PSCT), Polymer Network Liquid Crystal (PNLC), or holographic switchable diffusers. The number of screens N in the stack should be such that the amount of haze from the N-1 transparent screens would be acceptable under dark conditions such as night driving.
[0096] The projector 11 , based on commands from the controller 10 , forms an image on one of the PDLC screens 13 . This is re-imaged by the subsequent optics in the system including, for example, mirrors 14 , a variable power lens 15 , other fixed optics 16 , and a combiner 17 to form a virtual image that appears to be some distance away from the driver 18 . Depending on the required image quality, the fixed optics 16 may or may not be present and could be placed before or after the variable power lens 15 . The fixed optics could include one or more spherical, aspherical, freeform, and diffractive elements in order to reduce distortion and optical aberrations in the virtual image.
[0097] The combiner 17 , for example, may be a piece of curved, high reflection dielectric coated partially transparent and partially reflective optical element. However, the combiner's shape may also be flat, curved, segmented, progressive powered, segmented prism, or Fresnel lens profiled and can also be metallic or holographic coated.
[0098] FIG. 2 shows that the function of the lens 12 is to improve the collimation of the specular beam 22 a from the projector to produce a collimated scanning laser beam 22 b. A further function of the lens 12 is to control the beam waist radius 100 to be no larger than twice the effective pixel size of the projector. The beam waist radius is the distance from the beam axis where the intensity drops to 13.5% of the maximum value. Whereas the effective pixel size of is given as the minimum of either the projector's pixel size on the screen or the resolution resolvable by the subsequent optics (e.g., 15 , 16 , 17 in FIG. 1 ). A further function of the lens 12 is to position the beam waist to be within (between the first screen and the last screen of) the PDLC stack, and to make the Rayleigh length 101 of the laser beam larger than or close to the axial span of all the PDLC screens. This allows an image with effective resolution of VGA or better to be displayed onto any screen without the need of an active focus modulator or a large physical system size. Although the lens 12 in the illustrated embodiment is a fixed lens, a second variable power lens can be used to actively focus the image onto the screen if the resolution of the image needs to be improved significantly beyond WXGA.
[0099] FIG. 3 illustrates an exemplary structure of the variable power lens 15 originally shown in FIG. 1 . The preferred lens is a liquid crystal (LC) lens with a continuously variable focal length. The component includes a Fresnel lens 15 b moulded from a transparent polymer, which is embossed within liquid crystal 15 a . The liquid crystal 15 a should meet the performance requirements for the automotive industry. The liquid crystal cell is sandwiched between two layers of transparent electrodes 15 c and substrate 15 d. The liquid crystal 15 a is rubbed in a way such that applying a voltage to the electrodes will change the effective refractive index of the liquid crystal 15 a as seen by incident light polarized by a polarizer 15 e. This creates a variable difference in refractive index between the polymer of the Fresnel lens 15 b and the liquid crystal 15 a, meaning that the power of the variable power lens 15 can be continuously varied by adjusting the amplitude of the applied voltage. However, other known configurations of liquid crystal lenses and known variable power lenses can also be used in the system. This includes, for example, the use of liquid lenses, switchable diffractive lenses, mechanical methods of varying the power of a lens, as well as known methods of varying the optical distance between a lens and the screen.
[0100] The profile of the Fresnel lens 15 b can take the form of any shape, including spherical, aspheric, and prisms. The substrate 15 d can be either flat or curved. However the longest linear dimension of the variable power lens 15 , after accounting for the magnification of the subsequent optics 16 and 17 , should be larger than the eye-to-eye distance 106 (See FIG. 5 ) of an ordinary driver 18 . In this way, a virtual image with the size at least as large as the lens 15 will be simultaneously visible to both eyes.
[0101] FIG. 4 shows the exemplary HUD system at the level of electronics signal. In the preferred HUD system, graphical signal 25 sent to the projector 11 is time synchronized with a switching sequence generated by a voltage controller 24 and provided to the screens 13 a - 13 d as well as voltage 23 for controlling the focal length of the variable power lens 15 . The graphics signal 25 can be sequences of image frames, but can also be any general instructions to steer the laser beam to arbitrary positions. A synchronization unit 26 , which can be implemented at the software level using the controller 10 or other processing device, coordinates the graphics signal 25 provided to the projector 11 , the voltage controller 24 for generating the switching sequence of the screens 13 a - 13 d and the voltage 23 for controlling a focal length of the variable power lens 15 .
[0102] FIG. 5 a - b shows the operation of an exemplary HUD system. During operation, each screen 13 is switched by the controller 10 diffusive time sequentially, but only one screen (e.g., 13 b ) is switched diffusive at any given time, allowing a virtual image 21 to be formed in space at a distance 103 from the driver as depicted in FIG. 5 a.
[0103] Meanwhile, the controller 10 may continually sweep the power of the lens 15 from minimum to maximum back and forth (e.g., the focal length of the variable power lens may continually sweep between a first focal length and a second, different, focal length). FIG. 5 b shows that varying the lens's power allows the distance 102 of the virtual image 21 to be continuously varied over a limited range. This allows the image formed by each PDLC screen 13 a, 13 b, 13 c, and 13 d to be re-imaged to anywhere within a respective continuous volume 20 a, 20 b , 20 c, and 20 d. The switching order of the screens and the voltage signal applied to the LC variable power lens 15 could also depend on the content being displayed. The image volumes 20 a - 20 d may or may not overlap. Having a non-overlapping volume means that a weaker LC variable power lens 15 can be used hence leading to a faster switching speed; whereas having an overlapping volume may allow reduction in image flickering in cases where the switching cycle time of the screens exceeds the switching time of the LC variable power lens 15 .
[0104] The combinatorial effect of the LC variable power lens 15 and the PDLC screen means that the LC variable power lens 15 would not be required to very thick while still allowing the image to be displayed within a large volume. Since the switching time of liquid crystal-filled cells scales with the square of the cell gap thickness, increasing the number of screens would improve the switching speed of the system quadratically. This significant improvement enables a full continuously volumetric system to be made from automotive grade liquid crystals—which could not be achievable in the known prior art. Secondly, the weak LC variable power lens 15 would allow the embossed Fresnel lens structure to have a smaller gradient, leading to lower fabrication tolerance requirements and costs, as well as better image quality due to reduction in liquid crystal splay, bend, and twist that arises from non-uniform cell gaps.
[0105] FIG. 6 a shows an exemplary safety feature which can help the system meet automotive standards. To prevent the specular laser beam from being visible to the driver under possible instances where none of the screens are fully diffusive, the laser projector 11 can be offset from the subsequent optics. FIG. 6 b shows the same optical arrangement as FIG. 6 a but with the fold mirrors 14 removed to show more clearly the possible arrangement of the projector 11 . The projector 11 can be offset at a distance 109 and/or an angle 110 from the optical axis of the subsequent optics (e.g., 15 and 16 ) such that the scanning specular beam path 111 would never intercept these components (e.g., 15 and 16 ). If all screens are simultaneously transparent, the specular laser beam will be directly incident onto a beam block 19 or onto other non-glossy elements such that none of the specular beam will exit the system through other optics such as 15 and 16 . The tilt angle of the projector should be just large enough for the specular beam not to escape from the HUD enclosure, as a tilt angle that is too large (e.g., >20 degrees) may introduce haze in the image.
[0106] Subsequent embodiments described below are made in reference to the first embodiment and only the differences between the subsequent embodiments and the first embodiments are discussed.
[0107] A second embodiment of the system is shown in FIG. 7 . In the case where continuously variable image depth is not required, the variable power lens 15 from the first embodiment is not needed and thus is omitted from FIG. 7 . In this case, the projector's specular beam is still permanently hidden from the driver's access.
[0108] FIGS. 8 a -8 b illustrate a third embodiment that includes a laser projector 11 , switchable projector screens 30 a - 30 d (collectively referred to as switchable projector screen 30 ), and variable power lens 15 . This embodiment differs from the main embodiment as the switchable projector screens 30 are pixelated or partitioned such that only a portion of the same screen can be switched diffusive at any given time (rather than the whole screen being switched uniformly diffusive or transparent). The material of the screen could be, but is not limited to, PDLC.
[0109] This system enables images 31 , 32 to be perceived by a driver 18 at different depths 104 , 105 , where the images are displayed to the driver simultaneously without the need of temporally switching on and off different screens.
[0110] FIG. 9 is the same embodiment shown in FIGS. 8 a -8 b and illustrates how the system can benefit from spatial multiplexing by showing a dashboard image 31 in one screen's partition 30 d and traffic information image 32 on another screen's partition 30 b. This would be advantageous in cold conditions where the switching speed of the screens may slow down significantly. It should be noted that, unlike JP2004168230A, the image quality in this embodiment does not depend on the size of the pixels. Instead, the image quality of this system depends solely on the projector's resolution and the laser beam waist. This means the screens can be coarsely pixelated to achieve spatial multiplexing. Since full volumetric images displayed in automotive HUDs usually contain large patches of blank space, coarsely pixelated screens would allow high resolution images to be displayed without expensive requirements in computational power.
[0111] FIG. 10 illustrates a fourth embodiment where the projector 11 is arranged to be physically closer to the screen 40 d than all other screens ( 40 a - c ), where 40 d represent the screen that is optically closest to the driver 18 . In this embodiment, the virtual image comes from back scattered light from the switchable screens 40 . The screens 40 can be made of known materials with a satisfactory backscattering efficiency such as Polymer Stabilized Cholesteric Texture (PSCT). The last screen 40 a (i.e., the screen optically furthest from the driver 18 ) may be replaced by a permanent diffuser. This means if the screens are anti-reflection coated, there will be no need to use a beam block in the system.
[0112] In addition, one of the mirrors 14 from the first embodiment can be replaced by a partially transparent mirror or a beam splitter 41 to allow the projector's beam to reach the screens, but the mirror can also remain fully reflective if it is not obscuring the projector's light. This embodiment allows more flexibility in the folding up of the HUD system without potentially exposing the projector's exit pupil to the driver when none of the screens are fully diffusive at any instance.
[0113] FIG. 11 illustrates a fifth embodiment where a stack of switchable screens 50 is used instead of the screens 13 proposed in the first embodiment. When the screens 50 are in the transparent state, the polarization state of light transmitted through the screens is preserved (i.e., the polarization of the light passing through the screen is unaltered or altered by a small amount such that a specular beam transmitted through the polarizer 51 would be safe for the driver). This allows polarized light coming from the projector 11 to be simply blocked by a polarizer 51 if all the screens are clear. Therefore, the specular laser beam is not visible to the driver and thus additional measures (e.g., off-axis geometry) to prevent such visibility are not needed. The screens 50 can be PDLC screens made of low birefringence polymers, switchable holographic diffusers, or any other known switchable screens that preserves polarization in the transparent state.
[0114] FIG. 12 illustrates a sixth embodiment where, instead of the variable power lens 15 as proposed in the first embodiment, a lens 60 capable of refocusing to a discrete number of focal lengths 107 a, 107 b, 107 c is used. The lens 60 , when combined with the stack of switchable screens, would be capable of producing a combinatorial number of virtual images. The large number of virtual images could be spaced closely enough such that their discrete depths are not distinguishable to an ordinary observer. The lens could be a diffractive type lens, birefringent lens, or other known tuneable multi-focal length lenses. An advantage of this embodiment is that it may be less costly to manufacture and have a faster switching speed compared to the first embodiment.
[0115] FIG. 13 illustrates a seventh embodiment where, instead of the switchable screens 13 , a stack of transparent display panels 70 containing pixels with full image resolution are used. The transparent display panels 70 can produce a continuous image depth and/or contribute to the combinatorial number of possible virtual image depth planes. These screens 70 can be a stack of transparent liquid crystal panels, organic light emitting diode (OLED), inorganic LED arrays, wave guide displays, or other known methods of non-projector type transparent displays.
[0116] FIG. 14 illustrates an eighth embodiment where, instead of using only one laser projector, two or more projectors 80 a - 80 c are used in the system. Each of the projectors 80 a - 80 c may be capable of simultaneously projecting different images onto one or more screens 81 a - 81 d. The projectors can be any known types of projectors, including laser scanning MEMs projector, Digital Light Processing (DLP) projector, LCD projectors, or Liquid Crystal on Silicon (LCoS) projectors. Light from each projector could be incident onto the screens at an oblique angle to avoid unwanted scattering from other screens to reduce haze. Because multiple projectors are used, high quality images can be achieved without the need to actively refocus images onto different screens.
[0117] In addition, if the screens are arranged such that they are not occluding each other from view, rapidly switching the variable power lens 15 would allow multiple volumetric images to be simultaneously visible to the driver. This could be achieved by spatially rearranging the screens, or by pixelating/partitioning the screens as described in the seventh embodiment.
[0118] FIG. 15 and FIGS. 16 a -16 b illustrate a ninth embodiment where an interference filter 90 with low transmission in the direction of the specular beam is used to attenuate the specular beam produced by the projector 11 . As such, the projector 11 could be aligned parallel to the viewing axis of the HUD, which would provide improved optical efficiency. The interference filter 90 could also be designed such that its transmission as a function of angle from the incident laser beam 92 ( FIG. 16 b ) is complementary to the luminance profile 91 ( FIG. 15 and FIG. 16 a ) of the PDLC screen 93 in the scattering state. This would allow the user to see an image with uniform brightness independent from viewing position. The interference filter 90 could be designed for a single wavelength or multiple laser wavelengths.
[0119] Although the invention has been shown and described with respect to a certain embodiment or embodiments, equivalent alterations and modifications may occur to others skilled in the art upon the reading and understanding of this specification and the annexed drawings. In particular regard to the various functions performed by the above described elements (components, assemblies, devices, compositions, etc.), the terms (including a reference to a “means”) used to describe such elements are intended to correspond, unless otherwise indicated, to any element which performs the specified function of the described element (i.e., that is functionally equivalent), even though not structurally equivalent to the disclosed structure which performs the function in the herein exemplary embodiment or embodiments of the invention. In addition, while a particular feature of the invention may have been described above with respect to only one or more of several embodiments, such feature may be combined with one or more other features of the other embodiments, as may be desired and advantageous for any given or particular application.
INDUSTRIAL APPLICABILITY
[0120] Industrial application will be mainly for automotive head-up-display systems. Application can be used in any vehicle for traffic information display. The HUD system can be fixed into the vehicle's dashboard by the automotive manufacturer or sold as individual components that could fit into any vehicles including uses for automotive training. The key advantage of the system is visual comfort. This is because the augmented reality display demonstrates all three dimensional depth cues, allowing information to be displayed at a variable distances as seen from the driver.
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A head-up-display (HUD) system includes at least one scanning laser projector operative to generate laser light, and a stacked array of multiple-switchable screens arranged relative to the projector to receive laser light generated by the projector, each screen of the stacked array of multiple-switchable screens spaced apart from one another and operative to switch between a transparent state and a diffusive state. A controller is operatively coupled to the stacked array of multiple-switchable screens, the controller configured to time sequentially switch each screen of the array from a transparent state to a diffusive state, wherein only one screen is switched to the diffusive state at any given time. An output of the projector is arranged at an angle or a distance from imaging optics succeeding the array of screens to prevent a specular beam emitted by the at least one scanning laser projector from intercepting the imaging optics succeeding the array of screens when all screens are in the transparent state.
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BACKGROUND OF THE INVENTION
The art of drawing blood from patients for testing purposes has in recent years centered around the use of blood drawing devices that utilize pre-evacuated containers or tubes in which the blood tests are actually carried out. These devices normally include a dual needle assembly which includes a hypodermic needle and a tap needle which is used for tapping the evacuated container. To facilitate the taking of multiple samples, such devices also include a holder for the evacuated containers. In use the holder is coupled to the needle assembly and serves as a holder for the container during the blood drawing process as well as a structure for guiding the tap needle and container stopper into a vacuum tapping relation at which the needle has penetrated the stopper and is in communication with the sterile contents of the vessel.
Certain problems are encountered in using pre-evacuated containers. For one, the blood withdrawals are sometimes so rapid as to cause collapse of the patient's vein. This is undesirable because the need then arises to seek out another vein to collect the blood specimen and with all the well known patient trauma that is associated with the use of hypodermic needles. Yet another problem which is encountered is that of mechanical hemolysis caused by a shearing action on blood cells that transpires with rapid movement of the blood through the assembly components. Such hemolysis results in unsatisfactory specimens that must be discarded and again secured from the patient.
The vein collapsing problems can be generally overcome by providing a suitable valve mechanism between the hypodermic needle and the evacuated container. This permits the hospital technician or other attendant to regulate the flow of blood under the action of the partial vacuum in the sterile container to a rate which avoids collapsing of the patient's vein. This flow regulation also tends to minimize mechanical hemolysis but a further avoidance of the problem results from the use of streamlined flow structures in the mounts for and at the proximal ends of the needles.
Various different types of valve arrangements have been advocated and used in the dual needle assemblies. Many have involved the use of complicated structures which are too expensive to utilize in disposable items. Others have parts that can be accidentally disassembled during use of the devices. This, of course, requires the technician to start over again with a new sterile assembly and under circumstances which frequently follow an initial penetration of patient tissue by the hypodermic needle. Yet other valve arrangement require the use of both hands in order to manipulate the valve, and under circumstances where it would be preferable to have one hand free to perform other tasks.
The need accordingly exists for an inexpensive needle assembly of the kind contemplated in which the parts are reliably coupled together and protected from disassembly during use and in which the blood flow can be easily and effectively regulated by the technician.
A general object of the invention is to provide improvements in blood drawing devices. One particular object is to provide improvements in dual needle assemblies that are used with evacuated containers in blood drawing devices. Still another object is to provide a needle assembly of the kind contemplated and wherein the blood flow may be regulated by the attendant by a simple means for constricting the passage through a resilient tube. Other objects of the invention are to provide a simple, inexpensive means for regulating the flow of blood between the needles of a dual needle assembly and which during the process of manufacturing the disposable item, can be readily assembled by the workers. Other objects will be evident hereinafter.
STATEMENT OF THE INVENTION
The inventor provides a disposable dual needle assembly in which the proximal ends of the hypodermic and tap needles are connected by a resilient tube structure that is housed in a housing which is equipped with an exteriorally manipulatable push button that is used for constricting the passage through the tube to thus limit the blood flow through the assembly to the evacuated container. The arrangement provided protects the tube from being disconnected from the needle mounts yet simultaneously permits the valving action to be accomplished by a simple compression of the tube through finger manipulation of the push button. In accord with certain aspects of the invention, the housing is a simple extrusion which is provided with opposite end openings in which the needles are mounted. Between the openings, the extrusion is equipped with opposite side walls, one being equipped with an opening for the push button that is manipulated at the exterior of the housing while the other provides an interior surface against which the tube is compressed. In accord with other aspects of the invention, the push button is equipped with a lateral stop arrangement that permits it to be forced through the lateral opening during the assembly of the device but which in the final assembly engages an interior surface of the side wall to prevent withdrawal of the button from the housing. Other aspects of the invention have to do with a housing in which the interior surfaces of the opposite side walls are non-symmetrically located in reference to the center axis of the housing so as to provide a close physical relation between the tube and wall against which it is compressed by the push button and to also provide an arrangement that tends to minimize the excursion required of the push button to effectuate tube compression.
In the preferred embodiment, the needles of the disposable needle assembly are mounted at their proximal ends in mounting members which are press fit in the end openings of the housing and provided with outer portions that may be equipped with a means for attaching the needle assembly to the container holder. The mounting member is adapted at its inner end to receive the end of the tube. The mounting member of course, has a bore or channel in which the needle is mounted and at the proximal end of the needle, the mounting member is equipped with a contoured enlargement that aids in reducing mechanical hemolysis during use of the device.
BRIEF DESCRIPTION OF THE DRAWINGS
The novel features which are believed to be characteristic of this invention are set forth with particularity in the appended claims. The invention, itself, however, both as to its organization and method of operation, together with further objects and advantages thereof, may best be understood by reference to the following description taken in connection with the accompanying drawings, wherein:
FIG. 1 is a top plan view of a disposable dual needle assembly embodying the principles of the invention;
FIG. 2 is a longitudinal sectional view in elevation taken generally along the Lines 2--2 of FIG. 1;
FIG. 3 is a transverse sectional view taken generally along the Lines 3--3 of FIG. 2;
FIG. 4 is an end elevational view at the hypodermic needle end of the assembly as taken generally along the Lines 4--4 of FIG. 2, with certain parts in section;
FIG. 5 is an end elevational view at the vacuum tap needle end of the assembly as generally seen along the Lines 5--5 of FIG. 2;
FIG. 6 is a horizontal section through a fragment of the assembly as seen along the Lines 6--6 of FIG. 2;
FIG. 7 is a transverse section taken generally along the Lines 7--7 of FIG. 2;
FIG. 8 is a longitudinal section at the vacuum tap end of the needle assembly illustrating its operating relation to an evacuated container and holder therefor, the container and holder being shown in section; and
FIG. 9 is a transverse section taken generally along the Lines 9--9 of FIG. 8.
DESCRIPTION OF PREFERRED EMBODIMENT
Reference is now made to the drawings and wherein a disposable dual needle assembly embodying the invention is generally designated at 10. The assembly 10 serves as a component of a disposable blood drawing device 11 (FIG. 8) that in addition to the needle assembly 11, includes an evacuated container 12 which has a sterile interior that is under a partial vacuum and a holder component 13 in which the container 12 is held. Holder 13 serves to hold the container 12 when its vacuum is being tapped and it also serves in guiding the tap needle and container into a vacuum tapping relation seen in FIG. 8.
The needle assembly 10 includes a hollow hypodermic needle 15, a hollow vacuum tap needle 16, a pair of needle mounting members 17 and 18, an elongated, resilient tube 19 which interconnects the needles, and an elongated housing 20 which is equipped with a push button 21 for constricting the tube passage 22 so as to limit the blood flow through the assembly 10.
The housing 20 is an elongated, cylindrical member which is preferably extruded from a suitable thermoplastic material. The housing 20 has opposite end openings 24 and 25 in which the needles 15 and 16 are mounted by means of members 17 and 18. The housing 20 is equipped with opposite side walls 26 and 27 which extend between the opposite end openings 24 and 25. Between the opposite ends 30 and 31 of the housing, the top side wall 26 is equipped with a lateral opening 32 in which the button 21 for regulating the blood flow is mounted.
In the interior of housing 20, side walls 26 and 27 have planar surfaces 28 and 29 respectively and which are offset from the center axis 33 of the housing 20 and arranged in parallel. The bottom side wall surface 29 is offset from the axis 33 by a distance which is slightly greater than the radius of tube 19 so that in the assembly 10, the excursion requirement for the push button 21 to accomplish obstruction of the tube passage 22 is minimal. The top wall surface 28, on the other hand, is offset from the center axis 33 by a distance which is greater than that of the bottom wall surface 29 so as to accommodate the location of the inner end 35 of push button 21.
Push button 21 is a generally cylindrical element that is preferably made from a somewhat resilient plastic material so as to permit deformation of the stop discussed below during the assembly of the component. Button 21 is mounted in the lateral opening 32 of housing 20 and as arranged, the push button 21 is mounted for substantially linear movement in the opening 32 along an axis 37 which is normal to the center axis 33 of the housing. Push button 21 can be moved inwardly to pinch or compress the tube, as into the position shown at 34, by exerting finger pressure against the outer end 36 of the button. As this happens, the inner end 35 of the button moves inwardly and compresses the tube 19 against the inner surface of the bottom side wall 27 to thereby constrict the passage 22.
At its inner end 35, the push button 21 is equipped with a pair of lateral projections 38 and 39 which are arranged at the opposite sides of the button so as to serve as stop elements in limiting outward movement of the button. The button snuggly fits in the lateral opening 32 and the projections or protuberances 38 and 39 are each equipped with an inclined side surface 40 as well as another surface 41 that lies in a plane normal to the button axis 37. The arrangement of the inclined surface 40 is such as to permit the button to be inserted in the opening 32 from the housing exterior during the assembly of the components of assembly 10 and to a point at which the projections 38 and 39 pass through the opening 32 to a location in the interior of the housing. At this point in the assembly of the device 10, the button more or less snaps into place. Thereafter the protuberances 38 and 39 serve as stop elements that prevent the withdrawal of the button 21 from the opening because outward button movement causes the upper surfaces 41 of the projections 38 and 39 to engage the inner surface 28 of wall 26 and thus stop further outward movement of the button.
The needle mounting members 17 and 18 are identical in structure. Each member has a central portion 45 which generally conforms in shape to that of the end openings 24 and 25. The arcuate side walls 44 of the central portion 45 is equipped with a pair of side ribs 46 that provide a tight fit between the parts when the mount is press fit in the appropriate end opening of the housing. These needle mounting members also have an outer portion 47 which is equipped with a pair of opposite arcuate side walls 48 and a pair of opposite planar side walls 49. These walls 48 and 49 merge with a conical end wall 50 at the outer extremity of the member and which as seen in the drawings, converges upon the center axis 33. The needle mounts also have a cylindrical inner portion 51 which is adapted to fit in one of the opposite end openings 56 of tube 19. The inner portion 51 is provided with a circular rib 52 so as to again provide a tight fit when the tube is press fit onto the inner portion 51.
Each needle mount 17 and 18 also has a bore 53 for receiving the needle and which is coaxially arranged in the assembly 10 with the axis 33 of housing 20. At the outer end extremity of the needle mounting member, the bore 53 is flared to receive a suitable adhesive 54 which serves to fix the needle in the mount. The needle, of course, is received in the bore during the assembly of the device 10 and at its proximal end, each needle is flared and located in a streamlined enlargement 55 of the bore 53 and which serves to minimize the shear of blood cells as the blood leaves or enters the needles during use of the device.
The outer portion 47 of the tap needle mount 18 is equipped with a coupling 60 for releasably securing the assembly 10 to a holder 13 for the evacuated container 12. Coupling 60 includes a sleeve portion 61 which is adapted and arranged to fit on the outer portion 47 of member 18 and is crimped to the outer portion 47 by longitudinally extending crimps 62 and transverse crimps 63 that fit in transverse grooves 64 at the base of the planar side walls 49. The coupling 60 also has a pair of radially projecting flanges 65 at the opposite side walls 49 (FIG. 5) and which are used in coupling the assembly to the container holder 13.
FIGS. 8 and 9 best illustrate the arrangement for coupling assembly 10 to the evacuated container holder 13. Holder 13 has an open outer end (not shown) in which the evacuated container 13 is inserted in the process of using the device 11. At its base end 68, the holder 13 has an end wall 71 with a small central opening 69 that accommodates reception of the end extremity of the outer portion 47 of the vacuum tap needle mounting member 18 (FIG. 8). At its exterior, end wall 71 has an annular section 70 which is integrally formed with the end wall and which is provided at its outer extremity with a pair of diametrically opposite and radially inwardly projecting flanges 72. Flanges 72 are so spaced apart as to accommodate reception of the coupling flanges 65 therebetween in the process of coupling the assembly 10 to the holder 13.
When the radial flanges 65 of coupling 60 are received in the center opening 73 of annular section 70, rotation of assembly 10 a quarter turn rotates the flanges 65 to positions between the flanges 72 and the end wall 71 of holder 13. Here the flanges 65 become seated against integral stop portion 74 when the assembly 10 is coupled to the holder 13. Obviously the holder 13 and assembly 10 are disconnected by a clockwise quarter rotation (see FIG. 9) of assembly 10 relative to the holder 13 followed by axial movement of the components away from each other.
The dual needle assembly 10 is, of course, sterilized and to maintain sterile conditions, suitable caps 75 that fit on the outer portions 47 of the mounts 17 and 18 are provided to house the needles. These caps are, of course, removed to use the disposable assembly 10.
In normal use, the cap covering the hypodermic needle 15 is first removed and the assembly 10 is manipulated to penetrate and locate the end of the needle in the patient's blood vein. Thereafter, in the normal process of using the assembly, the cap covering the tap needle 16 end of the assembly is next removed and the container holder 13 is coupled to the assembly in the manner described in the consideration of FIGS. 8 and 9. As the holder is being attached to the assembly 10, the push button 21 may be pressed inwardly to close the passage 22 of tube 19 so as to prevent a flow of blood through the assembly under the blood pressure condition encountered in the patient's vein. Thereafter, and with the passage 22 closed off by the technician's finger pressure on button 21, the technician manipulates the stopper end of the evacuated container 12 into the holder 13 and to a point at which the stopper 57 is penetrated by the tap needle 16 and communicates with the evacuated interior of the container 12.
The arrangement of the tube 19 is, of course, such that the opposite ends of the passage communicate with the hollows of the needles. As such, when needle 16 penetrates the stopper 57 with the button depressed, a partial vacuum is created in the tube 19 up to the point at which the depressed button closes off the passage at the pinched position designated at 34. Thereafter the technician may gradually release the pressure on button 21 to regulate the flow of blood from the vein through needle 15, tube 19 and thence through tap needle 16 to the interior of container 12. As soon as the specimen is taken, of course, container 12 may be removed from holder 13 to take yet another blood specimen, all without the need for removing the assembly 11 from the patient's arm. During the exchange of containers, the technician may maintain button 21 at the depressed state that closes off the passage 22 to again prevent blood flow under the pressure conditions encountered in the patient's veins.
While only certain preferred embodiments of this invention have been shown and described by way of illustration, many modifications will occur to those skilled in the art and it is, therefore, desired that it be understood that it is intended herein to cover all such modifications that fall within the true spirit and scope of this invention.
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A disposable blood drawing device has an evacuated container and holder therefor as well as a dual needle assembly which is connectable to the holder. The assembly has an elongated housing with opposite end openings in which hypodermic and tap needles are respectively mounted and internally interconnected by a resilient tube that is compressable against one of the opposite walls of the housing by means of a push button which is manipulated exterially to compress and thus limit the flow through the resilient tube. The push button has a lateral stop element that will pass through an opening for receiving the push button during the assembly of the assembly but which engages the internal surface of one wall of the housing to prevent withdrawal of the button. The mounting for the tap needle carries an adaptor for connecting the device with the holder.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a pyrene derivative that emits light efficiently, has great heat resistance, permits an uniform film to be formed, and is morphologically stable, and further relates to a light-emitting element that has an anode, a cathode, and a layer including an organic compound from which luminescence can be obtained by applying an electric field (hereinafter, referred to as “a layer including a luminescent layer”).
2. Description of the Related Art
Organic compounds include more varied material kinds of materials in comparison with inorganic compounds, and have a possibility that a material that has various functions can be synthesized by an appropriate molecular design. Also, they have features that a molded article such as a film is flexible and excellent workability is provided by polymerization. Based on these advantages, photonics and electronics utilizing functional organic materials have been attracting attention recently.
For example, examples of a photoelectric device utilizing an organic semiconductor material as a functional organic material include a solar cell and a light-emitting device (also referred to as an organic electroluminescent device), which are devices utilizing an electric property (carrier transporting property) and an optical property (light absorption or light emission) of the organic semiconductor material, and, among them, the light-emitting device has been showing remarkable progresses.
The light-emitting device has a light-emitting element interposing a layer including a luminescent material between a pair of electrodes (an anode and a cathode), which is said to have the light emission mechanism that a hole injected from the anode and an electron injected from the cathode are recombined in the luminescence center of the layer including the luminescent material to form an excited molecule in an excited state when a voltage is applied between the both electrodes and energy is released to emit light while the excited molecule moves back toward the ground state. As the excited state, a singlet excited state and a triplet excited state are known, and luminescence is said to be possible through any of the singlet excited state and the triplet excited state.
In order to manufacture a full-color display by using the light-emitting element, it is necessary to arrange pixels that emit light of three primary colors of red, green, and blue. As a method for that purpose, there are various applicable methods. However, blue luminescence is indispensable in any method, and it is desired to provide a blue light-emitting element that is high in luminance, efficiency, and color purity.
Meanwhile, as a conventional blue light-emitting element, a light-emitting element using 1,3,6,8-tetraphenylpyrene or a derivative thereof as a luminescent material is known (refer to Patent Document 1 and Non-Patent Document1, for example). However, since a thin film of the luminescent material is likely to undergo crystallization, there is a problem that it is difficult to keep the film morphologically uniform and obtain stable light emission for a long stretch of time. Further, the luminous efficiency is insufficient.
(Patent Document 1)
Japanese Patent Laid-Open No. 2001-118682
(Non-Patent Document 1)
Wataru Sotoyama, et al., 2003 SID International Symposium Digest of Technical Papers, Vol. 34, 1294–1297 (2003)
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a pyrene derivative that permits an uniform film to be formed, and that is unlikely to undergo crystallization and morphologically stable. In addition, it is an object of the present invention to provide a light-emitting element from which stable light emission can be obtained for a long stretch of time and a light-emitting device using the light-emitting element.
A lot of earnest studies of the inventors have finally found out that a pyrene derivative represented by the following general formula (1) emits light efficiently and is unlikely to crystallize. Accordingly, an aspect of the present invention is a pyrene derivative represented by the following general formula (1).
(where R 1 to R 4 may be identical or different, and are individually any substituent selected form the group consisting of an alkyl group having 1 to 6 carbon atoms, an alkoxyl group having 1 to 6 carbon atoms, an aryl group, a diarylamino group, and a silyl group having one or more alkyl groups or one or more aryl groups.)
By using the pyrene derivative mentioned above, a light-emitting element from which stable light emission can be obtained efficiently for a long stretch of time can be manufactured. Accordingly, another aspect of the present invention is a light-emitting element including the pyrene derivative mentioned above. Since the pyrene derivative according to the present invention shows high-efficiency luminescence, it is preferable that the pyrene derivative mentioned above is included in a light-emitting layer.
The pyrene derivative according to the present invention permits an uniform film to be formed and is unlikely to undergo crystallization and morphologically stable. Therefore, stable light emission can be obtained for a long stretch of time by using the pyrene derivative according to the present invention for a light-emitting element. In addition, by using the light-emitting element according to the present invention, it becomes possible to obtain a light-emitting device that emits light stably for a long stretch of time.
BRIEF DESCRIPTION OF THE DRAWINGS
In the accompanying drawings:
FIG. 1 is a diagram illustrating a structure of a light-emitting element according to the present invention;
FIG. 2 is a diagram showing a result of a DSC measurement of a pyrene derivative;
FIG. 3 is a diagram showing a fluorescence spectrum of the pyrene derivative;
FIG. 4 is a diagram showing an UV-Vis absorption spectrum of the pyrene derivative;
FIG. 5 is a diagram illustrating a light-emitting device;
FIG. 6 is a diagram illustrating a structure of a light-emitting element according to the present invention;
FIG. 7 is a diagram illustrating a structure of a light-emitting element according to the present invention;
FIGS. 8A and 8B are diagrams illustrating a light-emitting device; and
FIGS. 9A to 9C are diagrams illustrating electronic devices.
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention is not limited to the following descriptions, and it is to be understood that various changes and modifications will be apparent to those skilled in the art unless such changes and modifications depart from the scope of the present invention. Therefore, the invention is not to be considered limited to what is described in the following embodiments.
(Embodiment 1)
A pyrene derivative according to the present invention has a structure represented by the above-mentioned general formula (1). Specific examples of R 1 to R 4 include alkyl groups such as a methyl group, an ethyl group, an isopropyl group, and a cyclohexyl group, alkoxyl groups such as a methoxy group, an isopropoxy group, and a hexyloxy group, aryl groups such as a phenyl group, a naphthyl group, and an anthryl group, diarylamino groups such as a diphenylamino group and a carbazolyl group, and a silyl group having one or more alkyl groups or one or more aryl groups.
In addition, by appropriately changing the structures of R 1 to R 4 in the general formula (1), pyrene derivatives represented by the following structure formulas (2) to (12) can be formed, for example. However, the present invention is not to be considered limited to these.
The pyrene derivative according to the present invention is large in molecular weight and has a three-dimensional structure since a phenyl group is bonded at the ortho position of a phenyl group bonded at each of 1-, 3-, 6-, and 8-positions of a pyrene. Accordingly, the pyrene derivative according to the present invention has not only great heat resistance but also a property of permitting an uniform film to be formed and a property of being unlikely to undergo crystallization, that is, being morphologically stable.
In addition, the pyrene derivative according to the present invention has a property of emitting light efficiently.
Various reactions can be applied to a synthesis method of the pyrene derivative according to the present invention. As a synthesis scheme of the pyrene derivative represented by the above-mentioned structure formula (2), there is the following method. However, the synthesis method of the pyrene derivative according to the present invention is not to be considered limited to this.
(Embodiment 2)
In the present embodiment, a light-emitting element using the pyrene derivative shown in Embodiment 1 will be described.
The structure of the light-emitting element according to the present invention is not particularly limited, which can be selected appropriately for any purpose. Basically, the structure has a layer including a luminescent material between a pair of electrodes (an anode and a cathode), which is formed by appropriately combining layers such as a hole injecting layer, a hole transporting layer, a light-emitting layer, a hole blocking layer, an electron transporting layer, and an electron injecting layer. For example, a light-emitting element that has a structure such as an anode/a hole injecting layer/a light-emitting layer/an electron transporting layer/a cathode, an anode/a hole injecting layer/a hole transporting layer/a light-emitting layer/an electron transporting layer/a cathode, an anode/a hole injecting layer/a hole transporting layer/a light-emitting layer/an electron transporting layer/an electron injecting layer/a cathode, an anode/a hole injecting layer/a hole transporting layer/a light-emitting layer/a hole blocking layer/an electron transporting layer/a cathode, or an anode/a hole injecting layer/a hole transporting layer/a light-emitting layer/a hole blocking layer/an electron transporting layer/an electron injecting layer a cathode, is included. In addition, the pyrene derivative according to the present invention is included in the light-emitting element according to the present invention, which may be included in any of a light-emitting layer, a hole transporting layer, a hole injecting layer, an electron transporting layer, and an electron injecting layer. Either the anode or the cathode may be laminated first.
Additionally, it is preferable that the light-emitting element according to the present invention is supported by a substrate. The substrate is not particularly limited, and a substrate that is used for a conventional light-emitting element, for example, a substrate including a material such as glass, quartz, or transparent plastic can be used.
As an anode material for the light-emitting element according to the present invention, it is preferable to use a metal, an alloy, an electrically conductive compound, or a mixture thereof, which has a large work function (a work function of 4.0 eV or more). As a specific example of the anode material, a metal such as gold (Au), platinum (Pt), nickel (Ni), tungsten (W), chromium (Cr), molybdenum (Mo), iron (Fe), cobalt (Co), copper (Cu), or palladium (Pd), and a nitride of a metal material such as TiN can be used in addition to indium tin oxide (hereinafter, referred to as ITO) and indium oxide including zinc oxide (ZnO) at 2 to 20%.
On the other hand, as a cathode material, it is preferable to use a metal, an alloy, an electrically conductive compound, or a mixture of these, which has a small work function (a work function of 3.8 eV or less). As a specific example of the cathode material, an alkali metal (such as Li, Na, K, or Cs), an alkali earth metal (such as Mg or Ca), gold, silver, lead, aluminum, an alloy or mixed metal of aluminum and lithium, and an alloy or mixed metal of magnesium and silver can be used. Further, between the cathode including the metal mentioned above and an organic layer, a metal oxide or a metal halide may be used as an electron injecting layer. As specific examples of the electron injecting layer, metal oxides such as lithium oxide (Li 2 O), magnesium oxide (MgO), and aluminum oxide (Al 2 O 3 ), and metal halides such as lithium fluoride (LiF), magnesium fluoride (MgF 2 ), strontium fluoride (SrF 2 ) can be used.
A thin film including the anode material and a thin film including the cathode material are formed by a method such as evaporation or sputtering to form the anode and the cathode respectively, which preferably have a film thickness of 10 to 500 nm.
In the light-emitting element according to the present invention, light generated by recombination of carriers in the layer including the luminescent material is emitted from one or both of the anode and the cathode to the outside. In other words, the anode is formed to include light-transmitting material in the case where light is emitted from the anode while the cathode is formed to include a light-transmitting material in the case where light is emitted from the cathode.
For the layer including the luminescent material, known materials can be used, and any of low molecular weight materials and high molecular weight materials can be used. The pyrene derivative according to the present invention is included in the layer including the luminescent material. The materials for forming the layer including the luminescent material includes not only organic compounds but also an inorganic compound included in a portion of the layer including the luminescent material.
The layer including the luminescent material is formed by appropriately combining layers such as a hole injecting layer including a hole injecting material, a hole transporting layer including a hole transporting material, a light-emitting layer including a luminescent material, a hole blocking layer including a hole blocking material, an electron transporting layer including an electron transporting material, and an electron injecting layer including an electron injecting material, which may have a single layer or have a laminated structure including a plurality of layers.
In the present invention, in the case of using the pyrene derivative for the light-emitting layer, the layer including the luminescent material can be formed by appropriately combining layers in addition to the light-emitting layer. In other words, the layer including the luminescent material can have a laminated structure by combining layers such as the hole injecting layer, the hole transporting layer, the hole blocking layer, the electron transporting layer, and the electron injecting layer as appropriate in addition to the light-emitting layer. Here are specific materials to be used in this case.
As the hole injecting material, porphyrin-based compounds are efficient among organic compounds. For example, phthalocyanine (hereinafter, referred to as H 2 -Pc) and copper phthalocyanine (hereinafter, referred to as Cu-Pc) can be used. In addition, a material of a chemically doped conductive polymer such as polyethylene dioxythiophene (hereinafter, referred to as PEDOT) doped with polystyrene sulfonate (hereinafter, referred to as PSS) can be used.
As the hole transporting material, an aromatic amine-based compound (that is, a compound that has a benzene ring-nitrogen bond) is preferred. As materials that are widely used, for example, in addition to N,N′-bis(3-methylphenyl)-N,N′-diphenyl-[1,1′-biphenyl]-4,4′-diamine (hereinafter, referred to as TPD), derivatives thereof such as 4,4′-bis[N-(1-naphthyl)-N-phenyl-amino]-biphenyl (hereinafter, referred to as α-NPD) and starburst aromatic amine compounds such as 4,4′,4″-tris(N-carbazolyl)-triphenylamine (hereinafter, referred to as TCTA), 4,4′,4″-tris(N,N-diphenyl-amino)-triphenylamine (hereinafter, referred to as TDATA), and 4,4′,4″-tris[N-(3-methylphenyl)-N-phenyl-amino]-triphenylamine (hereinafter, referred to as MTDATA) are included.
As the electron transporting material, a metal complex that has a quinoline moiety or a benzoquinoline moiety such as tris(8-quinolinolato)aluminum (hereinafter, referred to as Alq 3 ), tris(4-methyl-8-quinolinolato)aluminum (hereinafter, referred to as Almq 3 ), or bis (10-hydroxybenzo[h]-quinolinato)beryllium (hereinafter, referred to as BeBq 2 ), and bis (2-methyl-8-quinolinolato)-(4-hydroxy-biphenylyl)-aluminum (hereinafter, referred to as BAlq) that is a mixed ligand complex are preferred. In addition, there is also a metal complex that has an oxazole-based, thiazole-based, or benzimidazole-based ligand such as bis [2-(2-hydroxyphenyl)-benzoxazolato]zinc (hereinafter, referred to as Zn(BOX) 2 ), bis[2-(2-hydroxyphenyl)-benzothiazolato]zinc (hereinafter, referred to as Zn(BTZ) 2 ), or tris-(2-(2′-hydroxyphenyl)-1-phenyl-1H-benzimidazolate)aluminum (hereinafter, referred to as Al(PBI) 3 ).
In addition to the metal complexe, oxadiazole derivatives such as 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (hereinafter, referred to as PBD) and 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazole-2-yl]benzene (hereinafter, referred to as OXD-7), triazole derivatives such as 3-(4-tert-butylphenyl)-4-phenyl-5-(4-biphenylyl)-1,2,4-triazole (hereinafter, referred to as TAZ) and 3-(4-tert-butylphenyl)-4-(4-ethylphenyl)-5-(4-biphenylyl)-1,2,4-triazole (hereinafter, referred to as p-EtTAZ), phenanthroline derivatives such as bathophenanthroline (hereinafter, referred to as BPhen) and bathocuproin (hereinafter, referred to as BCP), and benzimidazole derivatives such as 2,2′,2″-(1,3,5-benzenetriyl)tris-[1-phenyl-1H-benzimidazole] (hereinafter, referred to as TPBI), 1,3,5-tris[4-(1-phenyl-1H-benzimidazole-2-yl)phenyl]benzene (hereinafter, referred to as TPBIBB), and 9-phenyl-2,4,5,7-tetrakis(1-phenyl-1H-benzimidazole-2-yl)-carbazole (hereinafter, referred to as PBIC) can be used.
As the hole blocking material, materials such as the above-mentioned BAlq, OXD-7, TAZ, p-EtTAZ, BPhen, and BCP can be used
In addition, the pyrene derivative according to the present invention can be used as a host material or guest material of the light-emitting layer.
In the case of using the pyrene derivative as a host material of the light-emitting layer, triplet luminescent materials (phosphorescent materials) such as tris (2-phenylpyridine)iridium (hereinafter, referred to as Ir(ppy)3) and 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrin-platinum (hereinafter, referred to as PtOEP) can be used as a guest material in addition to quinacridone, diethyl quinacridone (DEQ), rubrene, perylene, DPT, Co-6, PMDFB, BTX, ABTX, DCM, and DCJT.
In the case of using the pyrene derivative as α guest material of the light-emitting layer, materials such as TPD, a-NPD, 4,4′-bis (carbazolyl)-biphenyl (hereinafter, referred to as CBP), TCTA, PBD, OXD-7, BCP can be used as a host material.
As described above, a light-emitting element from which stable light emission can be obtained efficiently for a long stretch of time can be manufactured by using the pyrene derivative according to the present invention, which has material properties of emitting light efficiently, having great heat resistance, permitting an uniform film to be formed, and being unlikely to undergo crystallization and morphologically stable.
(Embodiment 3)
In the present embodiment, a light-emitting device according to the present invention will be described.
In the present embodiment, the light-emitting element using the pyrene derivative according to the present invention, which is shown in Embodiment 2, is manufactured over a substrate including a material such as glass, quartz, or transparent plastic. By manufacturing a plurality of light-emitting elements using the pyrene derivative according to the present invention over a substrate, a passive matrix light-emitting device can be manufactured.
In addition, other than the substrate including the material such as glass, quartz, or transparent plastic, for example, as shown in FIG. 5 , a light-emitting element in contact with a thin film transistor (TFT) array may be manufactured, and in this case, an active matrix light-emitting device where driving of a TFT is controlled by a TFT can be manufactured. In FIG. 5 , a TFT 11 and a TFT 12 are formed over a substrate 10 , to which a light-emitting element 13 is connected. Specifically, by applying a current from the TFT 11 to a first electrode 14 through a wiring 17 , an electric field is applied between the first electrode 14 and a second electrode 16 and a layer 15 including a luminescent material emits light. FIG. 5 shows gates of the staggered TFTs. However, The structures of the TFTs are not particularly limited. For example, a staggered TFT and an inversely staggered TFT may be used. In addition, the degree of crystallinity a semiconductor layer forming the TFT is not particularly limited, either. A crystalline semiconductor layer or an amorphous semiconductor layer may be used to form the TFT.
EXAMPLE 1
In the present example, an example of synthesizing the pyrene derivative represented by the above-mentioned structure formula (2) will be specifically exemplified.
First, in accordance with the above synthesis scheme (A-1), 10.4 g (44.8 mmol) of distilled 2-bromobiphenyl was added to a solution of dried tetrahydrofran (hereinafter, referred to as THF) in an atmosphere of nitrogen, and further, 31 ml of a 1.56 N hexane solution of n-buthyllithium (48 mmol) was dropped at −78° C. After the dropping, stirring was performed at −78° C. for 1 hour. After the stirring, the suspension was added to dried zinc chloride in an atmosphere of nitrogen, and stirring was performed at room temperature for 1 hour After the stirring, 4.64 g (9.0 mmol) of 1,3,6,8-tetrabromopyrene was added, and 517 mg (0.45 mmol) of tetrakis (triphenyl phosphine) palladium was further added. After that, reflux for 24 hours was performed. After the reflux, the solution was condensed to precipitate a solid, and the precipitated solid was washed with 3% hydrochloric acid, water, and ethanol, and further washed with hexane. Finally, the solid was washed with a small amount of THF to obtain 1,3,6,8-tetra-2-(phenyl)phenyl-pyrene (the above structure formula (2); hereinafter, referred to as TBiPy) that is light green powder, where the yield was 48%.
It was determined according to a TG-DTA measurement that the thermal decomposition temperature of the obtained TBiPy was 414° C. In addition, FIG. 2 shows a result of a DSC measurement. It is determined from FIG. 2 that glass transition temperature Tg is 148° C., crystallization temperature Tc is 260° C., and melting point Tm is 304° C. As described above, it is determined that the pyrene derivative according to the present invention has the high glass transition temperature, the high melting point, and the high thermal decomposition temperature, hence has great heat resistance. Further, the peak showing the crystallization temperature is not clear in FIG. 2 , which suggests that the pyrene derivative is a material that is unlikely to undergo crystallization. When vacuum deposition was used to deposit the pyrene derivative actually, it was possible to form a uniform film.
When a fluorescence spectrum of a thin film of the obtained TBiPy was measured, the obtained fluorescence spectrum had a maximum peak at 457 nm with respect to an excitation wavelength (355 nm) ( FIG. 3 ). In addition, when a UV-Vis absorption spectrum of a thin film of the obtained TBiPy was measured, a maximum absorption wavelength of 389 nm was obtained ( FIG. 4 ).
Further, the value of a HOMO level that was measured by using Electron Spectrometer for Chemical Analysis AC-2 (from Riken Keiki Co., Ltd.) is −5.77 eV. In addition, the value of a LUMO level that was estimated by adding the value of an absorption edge of the absorption spectrum ( FIG. 4 ), as an energy gap, to the value of the HOMO level is −2.79 eV.
EXAMPLE 2
In the present example, a case of using a pyrene derivative according to the present invention for a portion of a layer including a luminescent material to manufacture a light-emitting element, specifically, a structure in the case of a pyrene derivative according to the present invention for a light-emitting layer will be described with reference to FIG. 1 .
First, a first electrode 101 for a light-emitting element is formed over a substrate 100 . In the present example, the first electrode 101 functions as an anode. ITO that is a transparent conductive film is used as a material to form the first electrode 101 with a film thickness of 110 nm by sputtering.
Next, a layer 102 including a luminescent material is formed on the first electrode (anode) 101 . The layer 102 including the luminescent material in the present example has a laminated structure including a hole injecting layer 111 , a hole transporting layer 112 , a light-emitting layer 113 , a hole blocking layer 114 , an electron transporting layer 115 , and an electron injecting layer 116 .
The substrate over which the first electrode 101 is formed fixed in a substrate holder of a commercially produced vacuum deposition device with the surface at which the first electrode 101 is formed down, copper phthalocyanine (hereinafter, referred to as Cu-Pc) is put in an evaporation source provided in the vacuum deposition device, and then, the hole injecting layer 111 is formed by evaporation using resistance heating to have a film thickness of 20 nm. As a material for forming the hole injecting layer 111 , a known hole injecting material can be used.
Then, a highly hole transporting material is used to form the hole transporting layer 112 . As a material for forming the hole transporting layer 112 , a known hole transporting material can be used. In the present example, α-NPD is used to form the hole transporting layer 112 with a film thickness of 40 nm in the same way.
Then, the light-emitting layer 113 is formed. In the light-emitting layer 113 , a hole and an electron are recombined to generate luminescence (to emit light). In the present example, TBiPy that is a pyrene derivative according to the present invention is used as a material for forming the light-emitting layer 113 to form the light-emitting layer 113 with a film thickness of 30 nm by evaporation.
Then, the hole blocking layer 114 is formed. As a material for forming the hole blocking layer 114 , a known electron transporting material can be used. In the present example, BAlq is used to form the hole blocking layer 114 with a film thickness of 10 nm by evaporation.
Then, the electron transporting layer 115 is formed. As a material for forming the electron transporting layer 115 , a known electron transporting material can be used. In the present example, Alq 3 is used to form the electron transporting layer 115 with a film thickness of 20 nm by evaporation.
Then, the electron injecting layer 116 is formed. As a material for forming the electron injecting layer 116 , a known electron injecting material can be used. In the present example, calcium fluoride (hereinafter, referred to as CaF 2 ) is used to form the electron injecting layer 116 with a film thickness of 2 nm by evaporation.
After forming the layer 102 including the luminescent material, which is formed by laminating the hole injecting layer 111 , the hole transporting layer 112 , the light-emitting layer 113 , the hole blocking layer 114 , the electron transporting layer 115 , and the electron injecting layer 116 in this way, a second electrode 103 that functions as a cathode is formed by sputtering or evaporation. In the present example, aluminum (150 nm in film thickness) is formed by evaporation on the layer 102 including the luminescent material to obtain the second electrode 103 .
In this way, the light-emitting element using the pyrene derivative according to the present invention is formed.
When a voltage is applied to the formed light-emitting element, blue luminescence was observed at a voltage of 5 V or more, and at an applied voltage of 10 V, blue luminescence with a luminance of 2098 cd/m 2 (CIE chromatic coordinated of the luminescence: x=0.169, y=0.162) was observed. The luminous efficiency at the voltage of 10 V was 1.03 cd/A.
EXAMPLE 3
In the present example, a case of using a pyrene derivative according to the present invention as a guest material of a light-emitting layer will be described with reference to FIG. 6 . In the present example, structures of a first electrode, a second electrode, a hole injecting layer, a hole transporting layer, a hole blocking layer, an electron transporting layer, and an electron injecting layer are the same as those of Example 1. Accordingly, descriptions thereof are omitted.
Of a layer 202 including a luminescent material to be formed on a first electrode 201 , a light-emitting layer 213 to be formed to come in contact with a hole transporting layer 212 as shown in FIG. 6 is formed by using a host material and a guest material that is a pyrene derivative according to the present invention.
Specifically, CBP as the host material and TBiPy as the guest material are used to form the light-emitting layer 213 with a film thickness of 30 nm by co-evaporation. The ratio of the guest material was controlled to be 5 wt %.
Then, a light-emitting element using the pyrene derivative according to the present invention is formed over a substrate 200 by forming a second electrode 203 on the layer 202 including the luminescent material, which is formed by laminating a hole injecting layer 211 , the hole transporting layer 212 , the light-emitting layer 213 , a hole blocking layer 214 , an electron transporting layer 215 , and an electron injecting layer 216 in this way.
When a voltage is applied to the formed light-emitting element, blue luminescence was observed at a voltage of 7 V or more, and at an applied voltage of 10 V, blue luminescence with a luminance of 74 cd/m 2 (CIE chromatic coordinated of the luminescence: x=0.170, y=0.159) was observed. The luminous efficiency at the voltage of 10V was 1.43 cd/A.
The pyrene derivative according to the present invention has a high-efficiency light-emitting property. Therefore, the pyrene derivative can be used as a guest material of a light-emitting layer of a layer including a luminescent material, as shown in the present example. Further, the pyrene derivative according to the present invention has great heat resistance, permits an uniform film to be formed, and is unlikely to undergo crystallization and morphologically stable, which makes it possible to expand the life of a light-emitting element.
COMPARATIVE EXAMPLE 1
In the present comparative example, a case of using 1,3,6,8,-tetra(biphenylyl)pyrene (hereinafter, referred to as t(bp)py) as a guest material of a light-emitting layer will be described with reference to FIG. 7 , where the other structures are the same as those of Example 3.
Of a layer 302 including a luminescent material to be formed on a first electrode 301 , a light-emitting layer 313 to be formed to come in contact with a hole transporting layer 312 as shown in FIG. 7 is formed by using a host material and a guest material that is t(bp)py according to the present comparative example.
Specifically, CBP as the host material and t(bp)py as the guest material are used to form the light-emitting layer 313 with a film thickness of 30 nm by co-evaporation. The ratio of the guest material was controlled to be 5 wt % as in the case of Example 3.
Then, a light-emitting element using t(bp)py is formed over a substrate 300 by forming a second electrode 303 on the layer 302 including the luminescent material, which is formed by laminating a hole injecting layer 311 , the hole transporting layer 312 , the light-emitting layer 313 , a hole blocking layer 314 , an electron transporting layer 315 , and an electron injecting layer 316 in this way.
When a voltage is applied to the formed light-emitting element, blue luminescence was observed at a voltage of 6 V or more, and at an applied voltage of 10 V, blue luminescence with a luminance of 296 cd/m 2 (CIE chromatic coordinated of the luminescence: x=0.154, y=0.140) was observed. The luminous efficiency at the voltage of 10V was 1.03 cd/A, which is somewhat inferior to the case of Example 3 using the structure of the same sort. Further, this light-emitting element was morphologically deteriorated as compared with the cases of Examples 2 and 3.
EXAMPLE 4
In the present example, a light-emitting device that has a light-emitting element according to the present invention in a pixel portion will be described with reference to FIGS. 8A and 8B . FIG. 8A is a top view showing the light-emitting device and FIG. 8B is a cross-sectional view taken along line A–A′ in FIG. 8A . Reference numeral 601 indicated by a dotted line denotes a driver circuit portion (a source side driver circuit), reference numeral 602 denotes a pixel portion, and reference numeral 603 denotes a driver circuit portion (a gate side driver circuit). In addition, reference numerals 604 and 605 denote a sealing substrate and a sealing material, respectively. The inside surrounded by the sealing material 605 is a space 607 .
A leading wiring 608 is provided for transmitting signals to be input to the source side driver circuit 601 and the gate side driver circuit 603 , and receives signals such as a video signal, a clock signal, a start signal, and a reset signal from FPC (Flexible Printed Circuit) 609 that serves as an external input terminal. Though only the FPC is shown in the figure here, a printed wiring board (PWB) may be attached to the FPC. The light-emitting device in the specification includes not only a light-emitting device body but also a state where an FPC or a PWB is attached thereto.
Next, the sectional structure will be explained with reference to FIG. 8B . The driver circuits and the pixel portion are formed over a substrate 610 . Here, the source side driver circuit 601 as the driver circuit portion and the pixel portion 602 are shown.
In the source side driver circuit 601 , a CMOS circuit is formed of a combination of an n-channel TFT 623 and a p-channel TFT 624 . The TFTs forming the driver circuit may be formed of a known CMOS circuit, PMOS circuit, or NMOS circuit. Although the present example shows a driver integrated type in which a driver circuit is formed over a substrate, which is not always necessary, the driver circuit can be formed not over the substrate but outside the substrate.
The pixel portion 602 has a plurality of pixels, each including a switching TFT 611 , a current controlling TFT 612 , and a first electrode 613 electrically connected to a drain of the controlling TFT. In addition, an insulator 614 is formed to cover an edge of the first electrode 613 . Here, a positive photosensitive acrylic resin film is used to form the insulator 614 .
Besides, in order to obtain a favorable coverage, the insulator 614 is made to have a top portion or bottom potion formed with a curved surface with a curvature. For example, in the case of using positive photosensitive acrylic as a material for the insulator 614 , it is preferable that only a top portion of the insulator 614 has a curved surface with a curvature radius (0.2 μm to 3 μm). In addition, any of a negative photosensitive material that becomes insoluble in an etchant by light and a positive photosensitive material that becomes soluble in an etchant by light can be used as the insulator 614 .
On the first electrode 613 , a layer 616 including a luminescent material and a second electrode 617 are formed. Here, as a material to be used for the first electrode 613 that functions as an anode, it is preferable to use a material that has a large work function. For example, in addition to single layers such as an ITO film, an indium oxide film including zinc oxide at 2 to 20%, a titanium nitride film, a chromium film, a tungsten film, a Zn film, and a Pt film, laminated structures such as a laminate of a titanium nitride film and a film including aluminum as its main component and a three-layer structure of a titanium nitride film, a film including aluminum as its main component, and a titanium nitride film can be used. When a laminated structure is employed, the wiring has a lower resistance, favorable ohmic contact can be taken, and it is possible to function as an anode.
The layer 616 including the luminescent material is formed by evaporation that uses an evaporation mask or by inkjet. The layer 616 including the luminescent material includes a pyrene derivative according to the present invention. As a material to be used in combination with the pyrene derivative, low molecular weight materials, middle molecular weight materials (including an oligomer and a dendrimer) or high molecular weight materials may be used. In addition, as a material to be used for the layer including the luminescent material, it is often the case that an organic material is used for a single layer or laminate. However, the present invention includes a structure in which an inorganic compound is used for a part of a film including an organic compound.
In addition, as a material to be used for the second electrode (cathode) 617 formed on the layer 616 including the luminescent material, a material that has a small work function (Al, Ag, Li, or Ca; an alloy thereof such as MgAg, MgIn, AlLi, or CaF 2 ; or CaN) may be used. In the case of transmitting light generated in the layer 616 including the luminescent material through the second electrode 617 , it is preferable to use a laminate of a metal thin film that has a thinned film thickness and a transparent conductive film (such as ITO, indium oxide including zinc oxide at 2 to 20%, or zinc oxide (ZnO)) as the second electrode (cathode) 617 .
Further, the sealing substrate 604 and the substrate 610 are bonded with the sealing material 605 to have a structure where a light-emitting element 618 is provided in the space 607 surrounded by the substrate 610 , the sealing substrate 604 , and the sealing material 605 . The space 607 also includes a structure of filling with the sealing material 605 in addition to a case of filling with an inert gas (such as nitrogen or argon).
It is preferable to use an epoxy resin for the sealing material 605 . In addition, it is desirable to use a material that hardly allows permeation of moisture or oxygen. Further, as a material to be used for the sealing substrate 604 , a plastic substrate including FRP (Fiberglass-Reinforced Plastics), PVF (polyvinylfluoride), Mylar, polyester, or acrylic can be used besides a glass substrate and a quarts substrate.
In this way, the light-emitting device that has the light-emitting element according to the present invention can be obtained. In the case of this light-emitting device according to the present invention, crystallization in the light-emitting element is suppressed so that stable light emission can be obtained for a long stretch of time.
The light-emitting device shown in the present example can be implemented freely in combination with any of the structures of the light-emitting elements shown in Examples 1 to 3.
EXAMPLE 5
In the present example, various electronic devices completed by using a light-emitting device that has a light-emitting element according to the present invention will be described.
As examples of electronic devices equipped with a light-emitting device formed according to the present invention, a video camera, a digital camera, a goggle-type display (head mount display), a navigation system, a sound reproduction device (such as an in-car audio system or an audio set), a laptop personal computer, a game machine, a personal digital assistant (such as a mobile computer, a cellular phone, a portable game machine, or an electronic book), and an image reproduction device equipped with a recording medium (specifically, a device equipped with a display device, which can reproduce a recording medium such as a digital versatile disc (DVD) and display the image) can be given. FIGS. 9A and 9B show some specific examples of these electronic devices, which will be described.
FIG. 9A is a display device, which includes a frame body 2001 , a support 2002 , a display portion 2003 , a speaker portion 2004 , and a video input terminal 2005 . A light-emitting device formed according to the present invention is used for the display portion 2003 to manufacture the display device. The display device includes all devices for displaying information such as for a computer, for receiving TV broad casting, and for displaying an advertisement.
FIG. 9B is a cellular phone, which includes a main body 2701 , a frame body 2702 , a display portion 2703 , a voice input portion 2704 , a voice output portion 2705 , an operation key 2706 , an external connection port 2707 , and an antenna 2708 . A light-emitting device that has a light-emitting element according to the present invention is used for the display portion 2703 to manufacture the cellular phone.
As described above, a light-emitting device that has a light-emitting element according to the present invention is quite widely applied. In addition, since a pyrene derivative according to the present invention is used to form the light-emitting element that is used for the light-emitting device, the light-emitting element has features of a low driving voltage and a long lifetime. Therefore, it is possible to reduce power consumption and extend a lifetime (that is, favorable display images can be obtained for a long time) by applying this light-emitting device to electronic devices in all fields.
Although the present invention has been fully described by way of example with reference to the accompanying drawings, it is to be understood that various changes and modifications will be apparent to those skilled in the art. Therefore, unless such changes and modifications depart from the scope of the present invention hereinafter defined, they should be construed as being included therein.
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It is an object of the present invention to provide a pyrene derivative represented by the general formula (1) that is unlikely to crystallize and is superior in quality in the case of forming a film
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TECHNICAL FIELD
This invention relates to a TOUCH-TONE signal to dial pulse converter arrangement for communication switching systems and particularly to a common control circuit for determining the end-of-keying for a plurality of TT (TOUCH-TONE) to DP (Dial Pulse) converters on a time shared basis.
BACKGROUND ART
A substantial percentage of customer originated calls are presently keyed by callers using a TT telephone. The use of TT signaling has proven to be a valuable adjunct to telephone service in that it improves and simplifies customer "dialing" from a human factors standpoint and enables calls to be established more rapidly than with dial pulse signaling.
Many present day switching systems, such as the direct progressive or step-by-step systems, are basically designed to establish switching connections in response to dial pulse signals. In order to enable such systems to operate with customer TT telephones, it was necessary to equip the systems with facilities for converting the customer keyed TT signals into dial pulses.
Typically, such facilities include a plurality of converter circuits for serving a larger plurality of TT customer stations. A converter customarily is connected to a calling station for returning dial tone and then receiving and verifying the validity of the customer keyed TT digits. The converter usually converts the TT digits and then generates the dial pulses required for operating the switching network to extend the call toward its destination.
Efficient and rapid call processing requires that the TT to DP converter facilities ascertain when a calling customer has finished keying of a called customer number. This function permits a converter to complete its outpulsing operations, release rapidly from call connections and become available for serving other calls.
Despite the many innovations which have occurred in TT to DP converter arrangements, a recognized problem in the prior art has been the need for complex and expensive circuitry to be duplicated in each of the TT to DP converters in order to ascertain when the last TT digit has been keyed by a caller.
DISCLOSURE OF THE INVENTION
The foregoing problem is solved and a technical advance is achieved by the provision of a single end-of-keying control circuit for serving a plurality of TT to DP converters on a time division basis. Each of the converters is successively connected individually to the end-of-keying control circuit under control of a time slot allotter circuit and during an individual one of a plurality of repetitive time slots.
In each time slot, the end-of-keying control circuit receives two sets of input signals from the then connected converter. The first set of input signals represents the numerical value of one and more of the TT digits received by that converter. Such digits include, for example, dial zero, international, national and office code digits. The second set of input signals represents the actual number of TT digits received by the converter at that instant of the call. For example, the second set of input signals indicates how many digits have been received on a ten digit call and the actual number increases as TT keying progresses.
The end-of-keying control circuit comprises apparatus responsive to the first set of input signals for specifying the total number of digits expected to be received by the then connected one of the converters during the call. The control circuit is further equipped with circuitry which cooperates with the specifying apparatus and is responsive to the second set of signals for sending an end-of-keying signal to the then connected converter to indicate that the expected number of TT digits have been received. The converter can then operate expeditiously to complete call processing functions, such as outpulsing, and then release for serving other calls.
The specifying apparatus illustratively comprises a cross-connection field including a combinational logic circuit and a plurality of input and output terminals interconnected in a predetermined pattern. The apparatus also includes decoder circuitry responsive to a receipt of the first set of input signals in an n-out-of-x code for supplying to the input terminals of the cross-connection field output signals representing the decimal code value(s) of one and more of the TT digits received by the then connected converter at that point in the call.
A plurality of decoders are included in the decoder circuitry. Each decoder is responsive to separate ones of the first set of input signals for an individual one of the TT digits and for supplying to prescribed ones of the cross-connect input terminals output signals representing the decimal code value of the corresponding TT digit.
The specifying apparatus further includes encoder circuitry which is responsive to the receipt of coded signals from the cross-connect output terminals for generating signals specifying the total number of TT digits expected to be received during the call by the then connected converter.
Another aspect of the control circuit is that a comparator is utilized to compare the number of expected digits with the number of digits actually received and to send an end-of-keying control signal to the converter only during its assigned time slot and when the number of digits actually received are equal to or greater than the number of expected digits. It does so by comparing the signals generated by the encoder circuitry with the second set of input signals received from the converter.
In a preferred embodiment of the invention, the end-of-keying control circuit is integrated into a common translator which serves all of the converters on a time division basis. The translator functions during each time slot to translate keyed digit information into routing and outpulsing instructions for the converters.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a functional block diagram of a step-by-step telephone switching system utilizing this invention, and
FIG. 2 is a schematic diagram of the "end-of-keying" control circuitry in a common translator circuit.
The invention is particularly concerned with the common translator circuit which is represented by the block shown in heavy lines in FIG. 1. The other equipment units form part of the prior art and therefore are neither shown nor described in detail herein except where needed for a completed understanding of the invention.
DETAILED DESCRIPTION
The prior art circuitry as disclosed in FIG. 1 comprises rotary dial and TOUCH-TONE telephone stations 3 and 4 connected over respective telephone lines 5 and 6 to prescribed bank terminals 7 and 8 of a SXS line finder switch 9. A trunk circuit 10 extends connections from the line finder 9 selectively to a SXS first selector 11 toward a call destination and to a switching link 12 for TOUCH-TONE to dial pulse signal conversion on calls from station 4.
Link 12 is a switching network arranged to connect a plurality of trunk circuits, such as circuit 10, to a lesser plurality of TOUCH-TONE to dial pulse signal converters 13 and 14. Each of the converters 13 and 14, in a known manner, supplies dial tone, receives and verifies TOUCH-TONE digits, converts them to logic levels, stores the logic levels, and generates dial pulses for outpulse transmission through link 12 and the first selector 11 toward the call destination.
A time slot allotter circuit 15 connects a single translator 16 to each of the converters 13 and 14 on a time division basis. Each of the converters 13 and 14 is assigned a specific time slot in a cyclically recurrent time division frame. For example, assume that converters 13 and 14 represent a group of twenty-four converters which share translator 16, then a total of twenty-four time slots are used with each such slot being individually assigned to an individual one of the twenty-four converters.
During its time slot, a converter accesses the translator 16 with keyed digit information and receives back routing and control instructions needed for further processing a call. Typically, the converter supplies information on the dialed digits including international, area and office code digits as well as the total number of dialed digits on a call being served by the converter. Circuit 16 then translates that information and specifies the total number of dialed digits to be expected on the call. Translator 16 next compares the expected number with the actually received number. When the comparison indicates that the received number is greater than or equal to the expected number, the translator 16 signals the converter that the caller has completed TOUCH-TONE keying on the call.
FIG. 2 discloses the "end-of-keying" control circuitry 17. It comprises five fundamental building blocks, namely, decoder circuitry 18, a cross-connect field 19, a combinational logic circuit 30, an encoder 20, and a comparator 23.
The decoder circuitry 18 includes four decoders 24 through 27 each of which translates a respective one of the first four keyed digits of an international, area or office code. Each of the decoders, such as decoder 24, receives the respective one of the keyed digits via allotter 15 from a converter during each occurrence of its assigned time slot. The digits are received by each decoder over input leads in an n-out-of-4 signal format and are decoded into a 1-out-of-10 signal format on ten output leads which are, in turn, connected to ten cross-connect field terminals. Illustratively, the four leads 1-2, 1-3, 1-4, and 1-7 are inputs to decoder 24 and the ten output leads 24-1 through 24-10 are connected from decoder 24 to respective cross-connect field terminals 19-1 through 19-10.
The number of decoders 24-27 actually employed in a central office depends upon the numbering plan which the telephone system is designed to serve. For example, international dialing service customarily uses a translation of the first four digits received by a converter in order to determine how many digits it is expected to receive. Hence, four decoders 24-27 are provided for such service. Present day United States national numbering plan with zero plus (0+) and one plus (1+) type prefixing requires translation of the first or the first four digits received by a converter in order to determine how many digits it is expected to receive.
Cross-connect field 19 is arranged illustratively with forty input terminals 19-1 to 19-10 through 19-31 to 19-40. These terminals are cross-connected according to the numbering plan either directly to one or more of the fourteen output terminals 1-19 through 14-19 or to one or more of the terminals 19-41 to 19-50 which are connected through the combinational logic circuit 30 to terminals 19-51 to 19-55 which are, in turn, cross-connected to terminals 1-19 through 14-19 for specifying the number of digits expected to be received on the call served by the then associated converter. In the example to be described later with respect to a digit 9 access call, the input terminal 19-9 is cross-connected to terminal 8-19 to represent that eight digits are expected to be dialed by a caller in accordance with the office numbering plan.
The combinational logic circuit 30 is responsive to input signals on one or more of its ten input terminals 19-41 through 19-50 for combining those signals into an output signal on one or more of its five output terminals 19-51 through 19-55. The latter terminals are cross-connected to one or more of the terminals 1-19 through 14-19 in accordance with the local numbering plan.
Encoder 20 functions illustratively to translate 1-out-of-14 input signals on terminals 1-19 through 14-19 into n-out-of-4 binary output signals on the four leads 20-1 through 20-4. The latter signals form one set of inputs to the comparator 23 and are used to represent the number of digits which the "end-of-keying" control circuitry 17 specifies should be received by the converter on the call being served.
During each time slot, comparator 23 compares the signals on leads 20-1 through 20-4 with signals concurrently received on another set of four input leads 23-1 through 23-4 from the last-mentioned converter via allotter 15. The signals on leads 23-1 through 23-4 are in an n-out-of-4 binary format and are supplied by the converter to specify the number of digits which it has received at that instant of the call processing. Comparator 23 is responsive to the binary signals on the two sets of input leads for determining when the number of digits received by the converter equals the number of those expected to be received. When the two numbers are equal, comparator 23 sends an "end-of-keying" signal on lead 28 to the converter.
The operation of the control circuitry 17 of FIG. 2 is now described with reference to a digit 9 access call for which seven digits are expected to be received by the converter 14 following the caller TOUCHTONE keying of an initial digit nine. Time slot 1 of a time division frame of 24 time slots is illustratively assumed to be assigned for serving the call involving the converter 14.
During each recurrence of time slot 1, the time slot allotter 15 interconnects converter 14 and both the decoders 24-27 and the comparator 23 of FIG. 2. The decoder interconnections are established over the leads 1-2 through 1-7 and 4-2 through 4-7. The comparator 23 interconnections are over leads 23-1 through 23-4 and lead 28. It is significant to emphasize that the connections of converter 14 to the control circuitry of FIG. 2 persists only for the duration of the assigned time slot 1 and are opened during all other 23 time slots of the time division frame.
After the first digit, a nine, has been keyed by the calling station, such as station 4 of FIG. 1, following routine call origination and dial tone call processing, it is extended through line finder 9, trunk circuit 10 and switching link 12 to converter 14. The latter then converts the keyed digit nine signals into signals which are extended by allotter 15 illustratively to leads 1-2 and 1-7 of FIG. 2 during each occurrence of time slot 1. Decoder 24 decodes the received signals and applies an electrical signal to lead 24-9 and the cross-connect terminal 19-9 for signifying a receipt of a keyed nine as the first digit.
In accordance with the illustrative embodiment, terminal 19-9 is wire cross-connected to terminal 8-19 for specifying that eight digits are to be received by converter 14. Resultingly, the electrical signal on terminal 19-9 is extended over terminal 8-19 to encoder 20 which is then responsive for generating corresponding number signals on the output leads 20-1 through 20-4 to specify to comparator 23 that eight digits are to be received by converter 14 on the call. At the same time, comparator 23 receives number signals from the converter 14 to signify the then current number of digits which it has received.
The foregoing signal conditions and circuit operations persist on each subsequent repetition of time slot 1 except that converter 14 changes the binary number signal applied to leads 23-1 through 23-4 as each of the seven subsequent digits are keyed at station 4. When a comparison of the binary number signals on leads 20-1 through 20-4 and 23-1 through 23-4 indicates that they are equal, comparator 23 sending an "end-of-keying" signal over lead 28 which enables converter 14 via allotter 15 to recognize that caller keying has terminated and to proceed with other routine functions, such as called number dial pulsing through switching link 12, trunk circuit 10 and the first selector 11 toward the call destination.
Circuit 17 is also usable for determining the end-of-keying on other single digit and multidigit calls keyed by a caller. Illustratively, on a five digit call, the digits 234 are dialed as the first 3 digits and, accordingly, terminals 19-2, 19-13, and 19-24 are cross-connected to terminals 19-41 through 19-43 and the terminal 19-51 is cross-connected to terminal 5-19. When the digits 234 are registered in decoders 24, 25 and 26, respectively, the combinational logic circuit 30 provides a signal to terminal 19-51 and through the cross-connect field 19 to terminal 5-19 of the encoder 20. The encoder 20 and comparator 23 then function as previously described to generate the appropriate occurrence of the end-of-keying control signal on lead 28.
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A TOUCH-TONE signal to dial pulse converter arrangement isdisclosed in a step-by-step system. The arrangement is equipped with a plurality of trunk circuits interposed between line finder and selector switches for extending calls from TT (TOUCH-TONE) telephones through a switching network to a lesser plurality of TT to DP (Dial Pulse) converters. Each of the converters is time slot connected to a common translator under control of a time slot allotter. The common translator includes a single end-of-keying control circuit having decoders, a cross-connection terminal field, a combinational logic circuit, an encoder and a comparator for cooperating with all of the converters successively in individually assigned time slots to determine when the end-of-keying occurs on each call served by the converters.
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BACKGROUND OF THE DISCLOSURE
Many links in the chain of successful livestock production exist todaY. Each link or step is conducted in the geographic area which best utilizes the natural resources of the country. The cow-calf and the stocker-feeder operations are not usually adjacent to the confined finishing and slaughter processing facilities.
The cow-calf and stocker-feeder operations are by necessity located in the areas of open range and utilize roughages on lands which in general are not suited to intense agriculture food grain production, or they are adjacent to agriculture utilizing non-edible by-products of other grain and crop production.
The finishing-processing operations are usually near a bountiful supply of feed grains and near the slaughter processing facilities.
This geographic dislocation brings about multiple ownership throughout the red-meat food chain for cattle. It necessitates moving the livestock great distances, sometimes over thousands of miles from the grower areas to the finishing and processing areas. The geographic distribution of the stocker-feeder set the stage for many varying levels of animal husbandry and a great variance range in nutrition adequacy and/or deficiencies.
The net result is animals arriving to finishing facilities with all degrees of adequate and inadequate nutrition and the resulting nutrient levels of their tissues.
Shipping and handling stress coming at this time aggravates the deficiencies already existing and can cause other or increase deficiencies in the host animal and the rumen microbes.
This stress comes at a most inopportune time, the period of "Lot Adaptation", the period of least resistance and the period in the feeding program when the animals are challenged to create an immune response to build immunity to protect them during the remaining feeding period. The result is a period of highest disease incidence and animal health problems.
Lot adaptation is also a period of abrupt feed changes and the energy challenge in the feeding program to accomplish the production goals in the least amount of time possible.
The pathologies resulting from the above husbandry procedure are associated with the deficiencies of the geographic area of the source of the cattle, the deficiencies of the host animal and the deficiencies of the microbes of the rumen population must be addressed.
The transportation animal pathologies from stress and lack of food and water in transit are complex and a multiplicity of inner-actions exists.
The loss of energy in transit results in hypoglycemia to the rumen eco-system and the host animal with consistent slight ketosis during re-alimination. This hypoglycemia if not corrected can interfere with antibiotic response if it is needed to treat infectious diseases present.
A pronounced easinepia can exist when visible symptoms of ketosis appear. Hypoglycemia can also cause nervous irritability and further aggravate stress. In transit, loss of energy to the rumen microbes results in rapid depletion of the microbe population, the most pronounced clinical manifestation being loss of digestive functions due to a reduction of the normal cellulotic activity.
The microbial death of the rumen microbe eco-system is more time sensitive to lack of energy and proper nutrients than the death of the host animal. Starvation from inadequate energy begins within hours and fifty percent death can result in thirty to forty hours. Rumen pH of the eco-system increases as does the level of ammonia and lactates in the paunch media.
Long periods of water deprivation or short periods of water deprivation with elevated ambient temperatures results in reduced feed intake, and increased temperature. The body systems respond with corrective measures of blood volume, the kidney reacts conservatively, this results in the excretion of essential minerals as it struggles to maintain a correct osmotic mineral equilibrium in the cells of the host animal.
Mineral pathologies from deficiencies of origin and as a result of transportation and marketing stress exist. The deficiencies can be of the major and/or minor mineral group in animal nutrition and be evident for the rumen microbe population and the host animal.
Protein and vitamin deficiencies exist for the same reasons as listed above and they become evident to the rumen microbes and the host animal. The degrees of pathology developed depends on the severity and length of stress and the lack of adequate nutrition from the geographic area of origin.
Lot adaptation is the most critical husbandry period for the symbiotic-relationship that exists between the microbes of the ruminant and he host ruminant animal. There is no period of time in the feeding period that this symbiotic inter-dependence is more important. The proper and timely return of normal physiologic and peak function is of the most value to the owner for economical and efficient beef production.
Inadequate protein to the host animal can interfere with growth and the immune response.
Inadequate energy and resulting hypoglycemia interferes with appetite, causes clinical and sub-clinical ketosis and the potential lack of response to parenteral antibiotics.
The rumen microbes function in energy utilization, protein synthesis, mineral and vitamin utilization.
Microbial death of the ruminant eco-system will aggravate deficiencies of the host animal and seriously delay or prevent the animal's recovery to a normal state of physiology.
Therefore, any husbandry which interferes with the metabolism of the ruminant microbes will interfere with the metabolism of the host animal.
Conversely, any product which corrects the pathology of the systems of the rumen microbe population and the host, with speed, will hasten the correction of the pathology and return the host animal to an economic producing animal in the least time possible.
This invention involves a feed supplement which can be free choice fed, used as a drench or as a top dressing incorporated in the feed, and which has as one of its primary ingredients, propylene glycol. It has heretofore been recognized that propylene glycol can be an effective carrier for minerals and other supplements, see for example, Talbot, U.S. Pat. No. 4,202,887, issued May 13, 1983. However, what has not heretofore been appreciated or, as far as the inventor is aware, ever known, is that a synergistic occurrence happens when a feed supplement containing propylene glycol is made in the special manner in accordance with this invention.
The synergistic result is that such a feed supplement is effective for significant reduction in lot adaptation stress. If the same ingredients are mixed in a manner not in accordance with this invention, for example, simply lumping all of them together, the adaptation stress reduction in a short period of time is not achieved. While not wishing to be bound by theory, it is believed this result occurs because of the increased metabolic utilization of the nutrients which have been individually premixed with the propylene glycol.
Accordingly, a primary objective of the present invention is to provide a method for preparing a feed supplement which when administered will significantly reduce lot adaptation stress.
Another objective of the present invention is to prepare a feed supplement which when fed, corrects the pathology of the systems of the rumen microbe population, as well as the pathology of the livestock's own system, in such a manner that the host animal is quickly returned to an economic producing animal, in the shortest time possible.
Another objective of the present invention is to provide a lot adaptation feed supplement which aids in quickly reestablishing the symbiotic relationship that exists between the microbes of the ruminant and host ruminant animal.
Another objective of the present invention is to provide a livestock feed supplement which not only is effective in reducing lot adaptation stress during the initial days after an environment change, but also which provide continuing benefits throughout the entire finishing period, with a showing of significant economic benefits.
The method and manner of accomplishing each of the above objectives will become apparent from the detailed description of the invention which follows.
SUMMARY OF THE INVENTION
A method of preparing a feed supplement which comprises as major ingredients, molasses, preferably beet molasses, and propylene glycol, and as minor ingredients, at least protein mix, vitamin mix, trace mineral mix, and amino acids. In accordance with the method, each minor ingredient is separately and individually mixed with a small but effective amount of propylene glycol until substantial homogeniety is attained. Thereafter, each of the minor ingredient-propylene glycol components are themselves added to the beet molasses ingredient, and the remainder of the propylene glycol, if any, and mixing is continued until substantial homogeniety is achieved.
When this feed supplement composition, prepared as previously described, is administered to animals undergoing lot adaptation stress for from about 6 to about 12 days after environment change, lot stress is significantly reduced, and the animals are more quickly returned to a state of normalcy, and a more efficient livestock producing unit.
DETAILED DESCRIPTION OF THE INVENTION
The major ingredients of the composition of the present invention are molasses and propylene glycol. The amount of molasses can vary from about 25% to about 75% by weight of the composition. Preferably the molasses is beet molasses. It has been found that the synergistic action, attained by the process of this invention, is enhanced if the molasses that is employed is in fact beet molasses. The preferred beet molasses has a total invert sugar content of from about 56.5% to about 65%, with a total overall sugar solids content of about 48% being preferred as is a pH of about 7.5 and 79.5 brix. The preferred range of total solids content for the beet molasses is from about 65% to about 75%.
The other major ingredient of the composition is propylene glycol. The preferred amount of propylene glycol varies within the range of from about 1.5% by weight of the composition to about 15% by weight of the composition, with the preferred range being from about 5% to 14% by weight of the composition. The other ingredients are characterized as "minors". However, it should be understood that the term "minors" is not being used from the standpoint of their effect on the composition, but merely from the standpoint of a characterization of the amount that is present in comparison with the much higher weight percent levels of molasses and propylene glycol. The minors can vary from time to time depending upon the feed lot situation, but in most instances will include at least a protein mix, a vitamin mix, a major mineral mix, a trace mineral mix and an amino acid mix. The precise composition of each of these ingredients can also vary as desired without significantly changing the synergistic effect of the formulation composition. In other words, the ingredients can be tailored to the precise situation present in the feed lot animals. In most instances, however, it will almost always be that the ingredients will include protein mix, vitamin mix, major mineral mix, trace mineral mix and amino acids. The amount of the protein mix can be from 5% to 50%; the amount of the vitamin mix can be from 0.1% to 10%; the amount of the trace mineral mix can be from 0.4% to 5%, major mineral mix, i.e., calcium, phosphorous, potassium, nagnesium, 2% to 10%; and, the amount of amino acid mix can be from 10% to 70%.
With regard to the protein mix, typical ingredients contained therein can be natural protein from distillation solubles, materials often regarded as "chemical protein precursor" ingredients such as ammonium polyphosphate, ammonium phosphate, diammonium phosphate and urea.
The vitamin mix, as is preferred for processing, can be divided into a fat soluble mix portion including vitamins A, D and E and a water soluble vitamin portion including thiamine B 1 , choline, riboflavin B 2 , niacin, pantothenic acid, pyridoxine B 6 , folic acid, biotin, and vitamin B 12 .
The trace mineral mix, as is the case with the others, can vary in composition depending upon the condition of the animals being treated. Typically, however, the trace mineral mix will include zinc salts, manganese salts, iron salts, magnesium salts, copper salts, and cobalt salts, all preferably sulfate. In addition, the major minterals mix may include calcium in the form of calcium carbonate, chloride and/or sulfate, and sodium salts, such as sodium selenite and sodium selenate, and magnesium salts in the form of magnesium sulfate and often magnesium oxide, as well as potassium salts.
The amino acids are employed as amino acid solutions of methionine, lysine, glutamic acid, leucine, valine, alanine, glycine, aspartic acid, theonine, isoleucine, phenyl alanine, tryptophane, histodine, and arginine, as well as proline, serine, threonine, tyrosine, etc. The amino acid mix is a water solution, preferably with a solids content of from 30% to 60%.
In accordance with the method of this invention, each of the ingredients are separately admixed with a small but effective amount of propylene glycol, but with mixing continuing until substantial homogeneity is achieved. If the minors are soluble in propylene glycol, homogeneity will be achieved rapidly. If, however, they are not soluble, mixing may take a longer period of time. Generally, an amount of mixing of from about five to about ten minutes is sufficient. The amount of propylene glycol admixed with each individual component may vary from an equal weight amount up to several times an equal weight amount. However, with a minor ingredient having a substantial amount of water present, such as the amino acid, one can use considerably less than equal weight amounts, and in fact, as low as from about 10% to 15% by weight of the aqueous amino acid solution. Thus, the amounts that are expressed herein as equal amounts or up to twice an equal amount, are absolute weight amounts for each of the ingredients with the exception of the amino acid ingredient, which it is understood, is an aqueous solution. However, if one bases the amount of propylene glycol on the amount of solids present in the amino acid solution, then the general rule of an equal amount up to twice as much propylene glycol, applies. But if it is on a water basis, 10% to 15% by weight of the aqueous solution, assuming a concentration equal to that shown in the examples hereinafter.
While the above description has referred to physical mixing until homogeneous, it should be understood that in addition, a chemical phenomenon occurs between the propylene glycol and the ingredients. The minerals will chelate or coordinate with the propylene glycol; the fat soluble vitamins form a covalent adduct with propylene glycol by reversible conjugate addition and/or are involved in nucleophilic displacement or reversible hemi-ketal formation. This alters the partition coefficient and speeds the uptake, because of the resulting co-solvent action, that is mass action solubility. The water soluble vitamins and the amino acids both have improved mass action solubility because of their soluble nature in propylene glycol.
The temperature during this admixing does not appear to be important. Satisfactory results are obtained when each of the minor ingredients is at room temperature. The same is true with the propylene glycol.
After each of the individual components are separately admixed with the propylene glycol, they are thereafter added to the molasses ingredient. Mixing is continued for about another ten to fifteen minutes to assure substantial homogeneity. The product is now ready for use as a feed supplement.
The beet molasses ingredient is preferably at a temperature of about 100° F. prior to addition of the separately admixed minors-propylene glycol mixture. For process reasons, this has been found most desirable, although it is certainly not essential.
Certain other processing techniques are worthy of note. For example, the vitamin mix can be separated into a fat soluble portion and a water soluble portion, and ideally each is separately admixed with its own weight of propylene glycol prior to admixing them together.
For reasons that are not precisely understood, because of the uncertainty of the complete metabolic pathway, but clearly demonstrated in proven data, when the same composition is prepared but the ingredients are all simply lumped together and admixed, the composition is not nearly as effective as a treatment for lot feed adaptation stress. While the applicant does not wish to be bound by any theory, it is believed that the invention results are obtained because each one of the ingredients are individually and homogeneously admixed with the propylene glycol to allow the previously referred to intermolecular phenomenon to occur between each of the ingredients and the propylene glycol. This assures the necessary association and the intermolecular phenomenon such that the propylene glycol becomes an effective mainline carrier of the essential supplemental ingredients directly to the blood stream of the animal, and as well, to microorganisms in the rumen of the animal. As a result, both the microorganisms in the rumen, and the host animal itself, are properly, and quickly, and efficiently, returned to their normal symbiotic relationship, necessary for fast and efficient animal performance.
The feed supplement of this invention can be effectively used as a drench, or top dressing mixed in the feed ration and fed in a free choice manner. While the most dramatic effect is seen during the early part of the feeding period (first 30 days), the data does show continued economic advantage during an entire finishing period.
The following examples are offered to further illustrate but not limit the process, composition and method of this invention.
EXAMPLES
In each of the examples shown below for feed lot data, the composition used was prepared in the following manner.
A trace mineral mix, four pounds, which comprised 24.26% zinc sulfate, 24.26% magnesium sulfate, 16.04% iron sulfate, 23.76% magnesium sulfate, 3.17% copper sulfate, 3.17% cobalt sulfate, and 5.34% ethylene diamine hydroiodide was employed. Four pounds of this trace mineral mix were mixed with an equal amount of propylene glycol in a 6300 rpm mixer for ten minutes, until substantial homogeneity of the mix was obtained.
A 14 ounce package of fat soluble vitamins sold under the trademark Rovimix AD 3 and Rovimix E-40% by Roche Chemical Division of Hoffmann, LaRoche, Inc. was mixed with two pounds of propylene glycol in a similar manner for ten minutes at 6300 rpm.
Choline chloride, ten pounds, was mixed with ten pounds of propylene glycol for ten minutes at 6300 rpm. Two ounces of thiamine chloride were mixed with one pound of propylene glycol for ten minutes at 6300 rpm.
Two pounds of methionine were mixed with two pounds of propylene glycol for ten minutes at 6300 rpm.
One pound of leucine was mixed with one pound of propylene glycol for ten minutes at 6300 rpm.
One pound of niacin was mixed with one pound of propylene glycol for ten minutes at 6300 rpm.
14.5 pounds of ammonium polyphosphate was mixed with ten pounds of propylene glycol for ten minutes at 6300 rpm.
Eight hundred pounds of 48% aqueous amino acid solution was mixed with 90 pounds of propylene glycol for ten minutes at 6300 rpm. The amino acid solution which had a solids value of 48% comprised 7.9% alanine, 4.1% arginine, 8.8% aspartic acid, 14.3% glutamic acid, 5.5% glylcine, 2.9% histodine, 4.3% isoleucine, 8.1% leucine, 6.0% lysine, 1.3% methionine, 3.8% phenylalanine, 8.1% proline, 4.2% serine, 4.4% threonine, 2.9% tryosine, 0.6% tryptophane, and 5.7% valine.
One hundred pounds of filler suspension clay solution (10% sepiolite clay solution), 66 pounds of calcium carbonate, were mixed for five minutes at 6300 rpm. Thereafter, five pounds of potassium chloride was added with mixing continuing for five additional minutes, and 79 pounds of propylene glycol were then added to this portion of the mineral mix, with mixing continued another 15 minutes until substantial homogeneity was achieved.
Thereafter, each of the above separately mixed ingredients was added to a 665 pound batch of beet molasses, and mixing was continued until homogeneity was achieved, that is, for about ten additional minutes. The beet molasses had a solids content of 48% and 79.5 brix. The total batch weight was 2000 pounds. The beet molasses was at 100° F. and all of the remaining ingredients were at room temperature. The total weight percent basis of beet molasses in this batch was 32.25%. The total weight percent basis of propylene glycol in this batch was 9.5%.
This 2000 pound batch, or batches fully equivalent to this, were used in the feed lot test data shown below.
In the control shown in the test data below, a batch of exactly similar composition was prepared, except that individual ingredients were not separately admixed with propylene glycol, but all were simply dumped into the batch mixture simultaneously, along with the molasses and propylene glycol and admixed for 15 minutes. This latter composition where in toto mixing all at once was practiced, is referred to in the data below as "control".
TABLE I:
In Table I shown below, the cattle employed were all weaning calves which were shipped 170 miles to a growing facility. In transit shrink was noted to be the same in both groups, that is, the group treated in accordance with the invention and the control group. The cattle were arbitrarily separated into two equal groups, one for invention treatment, and one for control treatment. Their in-weight was taken, and their weight at the end of 28 days was noted. Each of the cattle were fed in the bunk on a top dress mixed, feed basis, either the invention or the control, for a period of ten days. Data was continually taken for a total of 28 days. The results are shown in Table I.
TABLE I______________________________________ INVENTION CONTROL______________________________________IN WEIGHT 426# 427.0#28 days weight 476# 465.1#Shrink 6.5% 6.5%Total gain 50# 38.1#Feed consumption 13.348# 12.253#Cost per day 51.231¢ 47.201¢Gain/lb/day 1.786 1.361Cost/lb/gain 28.685 34.681Efficiency* 119% 103%Conversion 7.47 9.00Number fed 1801 327RESULTS:1. Increased gain by .425/lb/day2. Increased fed efficiency 13.5%3. Improved cost of gain .0403¢4. Improved fed conversion $1.63/lb.______________________________________ *Based on the Net Energy System.
In another experimental test, taken over a fairly extended period of time, the same invention formulation and control formulation were employed with a much larger group of animals, in a variety of different feed lots, testing the efficiency for stress adaptation under a variety of conditions. The results are shown in Table II below:
TABLE II__________________________________________________________________________ Days on Effi- Cost/lb/Lot # # Head Supplement % Wt. Gain P/Gain ciency Gain__________________________________________________________________________CONTROL:191 154 0 3.05 2.44 3.09 78.96 45.89166 156 15 2.71 2.38 2.78 85.61 43.00 17 361 14 2.82 3.25 3.69 88.07 44.18 12 91 14 2.34 2.07 2.76 75.00 64.82195 89 10 2.46 2.55 2.90 87.93 44.36180 123 14.5 2.81 2.90 3.26 88.95 46.82144 74 32 3.05 2.90 3.52 82.38 39.82177 123 15.8 2.87 2.57 3.08 83.44 42.71161 22 27 3.26 3.35 4.58 73.14 45.81 14 71 0 2.12 2.01 2.34 85.89 61.62 15 47 10 2.23 2.16 2.60 15.07 61.39 16 364 10 2.65 2.89 3.25 88.92 41.36 10 622 12 2.67 2.81 3.28 85.67 43.36 6 418 16 2.69 2.75 3.25 84.61 43.52189 168 27 2.72 2.17 2.67 81.27 44.17 2883 13.54 2.71% 85.20 44.89INVENTION: 9 496 12.1 2.53 3.00 3.13 95.84 42.94160 234 25 2.80 3.13 3.41 91.78 38.39158 105 15 2.82 3.23 3.51 92.02 37.48153 148 35.7 2.59 3.00 3.07 97.72 42.27 4 40 24 2.56 2.82 2.74 102.91 46.91183 136 15 2.40 2.84 3.03 93.72 46.13164 144 13 2.42 2.47 2.47 100.00 49.14 1303 18.9 2.58% 95.47 42.75¢__________________________________________________________________________
As can be seen, those employing the invention involved a significant increase in efficiency and a decreased cost in pound gained.
It thus can be seen that the invention accomplishes at least all of its stated objectives.
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A method and composition designed especially to reduce livestock adaptation stress when livestock are transported. The composition comprises as major ingredients, molasses, preferably beet molasses, and propylene glycol and as minor ingredients, protein mix, vitamin mix, trace mineral mix, major mineral mix, and amino acids. Each of the ingredients are separately admixed with propylene glycol until substantial homogeneity is achieved, followed by adding each of the separately mixed ingredients to beet molasses. Thereafter, mixing is continued until complete homogeneity is achieved. The result of individual mixing of each minor ingredient with propylene glycol, prior to admixing all with beet molasses, provides a synergistic result in significantly reducing livestock stress during adaptation to new feed lot environments. The correction of the stress results in improved performance and reduced death loss.
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BACKGROUND OF THE INVENTION
The present invention relates to a method for providing advance notification of a parts shortage in a parts supply device of an electronic parts mounting machine.
An example of a conventional method for providing advance notification of a shortage of parts in a parts supply device mounted on an electronic parts mounting machine is described below.
FIG. 9 is a perspective view showing an electronic parts mounting machine 101. Reference numeral 102 denotes an operation panel of the electronic parts mounting machine 101 and reference numeral 103 denotes a monitor screen of the electronic parts mounting machine 101.
Conventionally, an operator manually inputs into the electronic parts mounting machine 101 an initial value denoting the quantity of parts held by the parts supply device 104 and an advance notification value denoting a parts shortage quantity by means of the operation panel 102. The electronic parts mounting machine 101 rewrites the quantity of parts held by each parts supply device 104 according to a parts mounting operation, and when the advance notification value has been attained, the operator is notified of a parts shortage by means of the monitor screen 103 in advance of the total exhaustion of parts.
However, the above-described method for providing advance notification of the shortage of parts held by the parts supply device in the electronic parts mounting machine has the following disadvantages:
(1) It is necessary for the operator to manually input to the mounting machine the initial value denoting the quantity of parts held by each parts supply device 104 and the advance notification value denoting a parts shortage quantity by means of the operation panel 102 and the monitor screen 103. In recent years it has become the practice to set tens to hundreds of parts supply devices on the electronic parts mounting machine 101, so that the above operation takes much time and labor and in addition, an erroneous input may occur. Further, when the parts supply device 104 which has been removed from the electronic parts mounting machine 101 is set thereon again, the operator does not know the quantity of parts held by each parts supply device and the operator thus cannot input the initial value denoting the quantity of parts mounted thereon into the electronic parts mounting machine 101.
(2) If a parts shortage suddenly occurs in the electronic parts mounting machine 101 without the time of the occurrence of the parts shortage being known, a parts mounting operation is suspended until another parts supply device 104 is prepared, and the operation rate of the electronic parts mounting machine 101 decreases.
(3) The operator does not know tho number of substrates comprising electronic parts set on the electronic parts mounting machine 101 in managing the number of substrates to be manufactured for the switch of one kind machine to another kind of machine.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to provide a method for providing advance notification to an operator of the shortage of parts held by each parts supply device in an electronic parts mounting machine, in which previous notification is given as to the order of the occurrence of a parts shortage in each parts supply device, the time of the occurrence of a parts shortage, and the number of substrates which can be manufactured, whereby the operator's parts shortage managing operation can be simplified and the operation rate of the electronic parts mounting machine can be improved by reducing the period of time for replacing one parts supply device with another due to the occurrence of a parts shortage.
In accomplishing these and other objects, according to one aspect of the present invention, there is provided an electronic parts mounting method for taking out from a parts supply device having a plurality of electronic parts at least one of the electronic parts, and mounting the part at a predetermined position of a substrate to be manufactured, comprising steps of:
storing a quantity of parts, which is held by each parts supply device, in a storing section provided in each parts supply device;
rewriting the quantity of parts according to number of parts taken out from the parts supply device by a calculating section provided in each parts supply device;
reading out an initial value of the quantity of parts held by each parts supply device, by a control section provided in an electronic parts mounting machine;
calculating one of the quantity of parts required for the substrate and period of time required for mounting the part on the substrate by a calculating section provided in the electronic parts mounting machine; and
carrying out in advance a parts shortage advance notification in each parts supply device based on a result of the calculating step.
As described above, according to the present invention, the operator is given advance notification of the order of the occurrence of a parts shortage in each parts supply device and the occurrence time of each parts shortage. Thus, the operator's parts shortage managing operation can be simplified and the operation rate of the electronic parts mounting machine can be improved by reducing the period of time for replacing one parts supply device with another due to the occurrence of a parts shortage.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other objects and features of the present invention will become clear from the following description taken in conjunction with the preferred embodiments thereof with reference to the accompanying drawings, in which:
FIG. 1 is a functional block diagram showing an apparatus for providing advance notification of an electronic parts shortage in an electronic parts mounting machine according to an embodiment of the present invention;
FIG. 2 is a flowchart showing the advance notification of an electronic parts shortage according to a first embodiment;
FIG. 3 is a flowchart showing the advance notification of an electronic parts shortage according to a second embodiment;
FIG. 4 is a flowchart showing the advance notification of an electronic parts shortage according to a third embodiment;
FIG. 5 is a flowchart showing the advance notification of an electronic parts shortage according to a fourth embodiment;
FIG. 6 is a flowchart showing the advance notification of an electronic parts shortage according to a fifth embodiment;
FIG. 7 is a display screen associated with the advance notification of an electronic parts shortage in the first, second, and third embodiments;
FIG. 8 is a display screen associated with the fourth and fifth embodiments; and
FIG. 9 is a perspective view showing an electronic parts mounting machine.
DETAILED DESCRIPTION OF THE EMBODIMENTS
Before the description of the present invention proceeds, it is to be noted that like parts are designated by like reference numerals throughout the accompanying drawings.
Referring to drawings, a method for advance notification of a parts shortage in a parts supply unit of an electronic parts mounting machine according to an embodiment of the present is described below.
FIG. 1 is a block diagram showing a method for providing advance notification of a parts shortage in an electronic parts mounting machine. In FIG. 1, the electronic parts mounting machine comprises a communicating section 1 for reading out data of the name and quantity denoting parts held by a parts supply device; a storing section 2 for storing data denoting the substrate production program of various kinds of apparatuses to be manufactured, data denoting the period of time required for mounting electronic parts on a substrate, and data denoting the number of substrates to be manufactured; a control section 3 for controlling the operation of the electronic parts mounting machine based on the above-described program and discriminating the order of the occurrence of a parts shortage in each parts supply device, the time to the occurrence time of parts shortage, and the number of substrates which can be manufactured prior to the parts shortage; a display section 4 for displaying on a screen the results obtained by the control section 3; and an input section 5 for receiving a request for the advance notification of a parts shortage made by an operator.
The processing flow of the advance notification of a parts shortage carried out in the above construction is described below with reference to the flowchart shown in FIG. 2.
At step #0, the parts supply device subtracts "1" from an initial value each time a parts is taken out from the parts supply device and stores the value obtained by the subtraction. At step #1, the input section 5 receives the operator's input of the advance notification value of the number of remaining parts, the number of substrates to be manufactured, and the occurrence time of a parts shortage and the storing section 2 stores the advance notification value, the number of substrates, and the occurrence time. At step #2, the communicating section 1 reads the initial value of the quantity of parts held by each parts supply device prior to the start of manufacture and the storing section 2 stores each initial value. At step #3, the communicating section 1 reads out the current value of the quantity of parts held by each parts supply device for each parts mounting operation. At step #4, the control section 3 calculates the number of substrates to be manufactured and the period of time required for manufacturing one substrate. At step #5, based on the subtraction ratio of the current value of the quantity of parts held by each parts supply device read out at step #3 and the period of time for manufacturing one substrate calculated at step #4, the control section 3 calculates the reduction ratio of the quantity of parts held by each parts supply device per unit time required for manufacturing one substrate. At step #6, based on the initial value of the quantity of parts held by each parts supply device read out at step #2 and the reduction ratio of the quantity of parts calculated at step #5, the control section 3 calculates the order of the occurrence of a parts shortage in each parts supply device, the occurrence time of the parts shortage, and the number of substrates which can be manufactured. At step #7, the control section 3 compares the advance notification value of the number of remaining parts inputted at step #1 with the current value of the quantity of parts held by each parts supply device obtained at step #2. If there is a parts supply device in which the advance notification value coincides with the current value, the control section 3 provides a parts shortage advance notification on the display section 4 as shown in FIG. 7 based on the result obtained by the calculation performed at step #6. At step #8, the control section 3 carries out a parts shortage advance notification on the display section 4 as shown in FIG. 7 based on the result obtained by the calculation performed at step #6, if the advance notification time inputted at step #1 coincides with the current time. At step #9, the control section 3 makes a parts shortage advance notification on the display section 4 as shown in FIG. 7 based on the result obtained by the calculation performed at step #6, if the advance notification value of the number of substrates to be manufactured inputted at step #1 coincides with the number of substrates to be manufactured obtained at step #4.
Whether a parts shortage has occurred is checked during the parts mounting operation, when an instruction of a parts shortage advance notification is inputted to the electronic parts mounting machine. At step #10, the control section 3 makes a parts shortage advance notification on the display section 4 as shown in FIG. 7 based on the results obtained by the calculation performed at step #6.
As described above, according to this embodiment, the operator is given advance notification of the order of the occurrence of a parts shortage in each parts supply device and the occurrence time of the parts shortage during the parts mounting operation. Thus, the operator's parts shortage managing operation can be simplified and the operation rate can be improved by reducing the period of time for replacing one parts supply device with another due to the occurrence of a parts shortage. In addition the parts supply device stores the current value of the quantity of parts mounted thereon and the reduction ratio of the quantity of parts mounted thereon is calculated. Thus, accurate advance notification of a parts shortage can be effected.
A second embodiment of the present is described below with reference to FIG. 3.
The method of the block diagram of FIG. 3 is similar to that of the first embodiment.
The processing flow of a part shortage advance notification is described below with reference to the flowchart of FIG. 3.
At step #1, the input section 5 receives the operator's input of the advance notification value of the number of remaining parts, the number of substrates to be manufactured, and the occurrence time of a parts shortage and the storing section 2 stores the advance notification value, the number of substrates, and the occurrence time. At step #2, the communicating section 1 reads the initial value of the quantity of parts held by each parts supply device prior to the start of manufacture and the storing section 2 stores each initial value. At step #3, the control section 3 subtracts "1" from an initial value for each parts mounting operation and then the storing section 2 stores the quantity of parts obtained as a result of the subtraction. At step #4, the control section 3 calculates the number of substrates to be manufactured and the period of time required for manufacturing one substrate. At step #5, based on the subtraction ratio of the current value of the quantity of parts held by each parts supply device read out at step #3 and the period of time for manufacturing one substrate calculated at step #4, the control section 3 calculates the reduction ratio of the quantity of parts held by each parts supply device per unit time required for manufacturing one substrate. At step #6, based on the initial value of the quantity of parts held by each parts supply device read out at step #2 and the reduction ratio of the quantity of parts calculated at step #5, the control section 3 calculates the order of the occurrence of a parts shortage in each parts supply device, the occurrence time of the parts shortage, and the number of substrates which can be manufactured. At step #7, the control section 3 compares the advance notification value of the number of remaining parts inputted at step #1 with the current value of the quantity of parts held by each parts supply device obtained at step #2. If there is a parts supply device in which the advance notification value coincides with the current value, the control section 3 provides a parts shortage advance notification on the display section 4 as shown in FIG. 7 based on the result obtained by the calculation performed at step #6. At step #8, the control section 3 carries out a parts shortage advance notification on the display section 4 as shown in FIG. 7 based on the result obtained by the calculation performed at step #6, if the advance notification time inputted at step #1 coincides with the current time. At step #9, the control section 3 makes a parts shortage advance notification on the display section 4 as shown in FIG. 7 based on the result obtained by the calculation performed at step #6, if the advance notification value of the number of substrates to be manufactured inputted at step #1 coincides with the number of substrates to be manufactured obtained at step #4.
Whether a parts shortage has occurred is checked during the parts mounting operation, when an instruction of a parts shortage advance notification is inputted to the electronic parts mounting machine. At step #10, the control section 3 provides a parts shortage advance notification on the display section 4 as shown in FIG. 7 based on the result obtained by the calculation performed at step #6.
As described above, according to the second embodiment, the operator is given advance notification of the order of the occurrence of a parts shortage in each parts supply device and the occurrence time of the parts shortage during the parts mounting operation. Thus, the operator's parts shortage managing operation can be simplified and the operation rate can be improved by reducing the period of time for replacing one parts supply device with another due to the occurrence of a parts shortage. In addition, the parts supply device stores the initial value of the quantity of parts mounted thereon and the reduction ratio of the quantity of parts mounted thereon is calculated. Thus, accurate advance notification of a parts shortage can be effected.
A third embodiment of the present is described below with reference to FIG. 4.
The method of the block diagram of FIG. 4 is similar to that of the first embodiment.
The processing flow of a parts shortage advance notification is described below with reference to the flowchart of FIG. 4.
At step #1, the communicating section 1 reads the initial value of the quantity of parts held by each parts supply device prior to the start of manufacture and then the storing section 2 stores each initial value. At step #2, when the operator checks whether a parts shortage has occurred before electronic parts mounting operation starts, the operator inputs a parts shortage advance notification instruction to the electronic parts mounting machine. At step #3, based on the initial value of each parts supply device read at step #1 and the production program stored in the storing section 2, the control section 3 calculates the occurrence time of an electronic parts shortage in each parts supply device, the order of the occurrence of the parts shortage, and the number of substrates which can be manufactured according to the quantity of parts using the program and the period of time required for mounting parts on a substrate, and a parts shortage advance notification is displayed on the display section 4 as shown in FIG. 7.
As described above, according to the third embodiment, the operator is given advance notification of the order of the occurrence of a parts shortage in each parts supply device and the occurrence time of the parts shortage before the parts mounting operation. Thus, the operator's parts shortage managing operation can be simplified and the operation rate can be improved by reducing the period of time for replacing one parts supply device with another due to the occurrence of a parts shortage. In addition, the parts supply device stores the initial value of the quantity of parts mounted thereon. Thus, accurate advance notification of a parts shortage can be effected.
A fourth embodiment of the present is described below with reference to FIG. 5.
The method of the block diagram of FIG. 5 is similar to that of the first embodiment.
The processing flow of a part shortage advance notification is described below with reference to the flowchart of FIG. 5.
At step #0, at the parts supply device, an initial count value is reduced by "1" each time a parts is taken out the parts supply device from and the quantity of remaining parts is stored in a memory of the parts supply device. At step #1, the communicating section 1 reads the initial count value of the quantity of parts held by each parts supply device prior to the start of manufacture and the storing section 2 stores each initial count value. At step #2, the communicating section 1 reads out the current count value of the quantity of parts held by each parts supply device for each parts mounting operation. At step #3, whether a parts shortage has occurred is checked during the parts mounting operation, when the instruction of a parts shortage advance notification is inputted to the electronic parts mounting machine. At step #4, based on the initial count value of the quantity of parts held by each parts supply device stored at step #1 and the current count value of the quantity of parts obtained at step #2, the control section 3 provides the display section 4 an instruction for displaying the use situation of parts of each parts supply device.
As described above, according to the fourth embodiment, the operator is given notification of the use situation of parts of each parts supply device is during the parts mounting operation. Thus, the operator's parts shortage managing operation can be simplified and the operation rate can be improved by reducing the period of time for replacing one parts supply device with another due to the occurrence of a parts shortage. In addition, the parts supply device stores the initial count value and the current count value of the quantity of parts mounted thereon. Thus, accurate advance notification of a parts shortage can be effected.
A fifth embodiment of the present is described below with reference to FIG. 6.
The method of the block diagram of FIG. 6 is similar to that of the first embodiment.
The flow of a part shortage advance notification is described below with reference to the flowchart of FIG. 6.
At step #1, the communicating section 1 reads the initial value of the quantity of parts held by each parts supply device prior to the start of manufacture and the storing section 2 stores each initial value. At step #2, the control section 3 subtracts "1" from an initial value for each parts mounting operation and then the storing section 2 stores the value obtained by the subtraction. At step #3, whether a parts shortage has occurred is checked during the parts mounting operation, when the instruction of a parts shortage advance notification is inputted to the electronic parts mounting machine. At step #4, based on the initial value of the quantity of parts held by each parts supply device stored at step #1 and the current value of the quantity of parts calculated at step #2, the control section 3 provides the display section 4 an instruction for displaying the use situation of parts of each parts supply device as shown in FIG. 8.
As described above, according to the fifth embodiment, the operator is given notification of the use situation of parts of each parts supply device during the parts mounting operation. Thus, the operator's parts shortage managing operation can be simplified and the operation rate can be improved by reducing the period of time for replacing one parts supply device with another due to the occurrence of a parts shortage. In addition, the parts supply device stores the initial value and the current value of the quantity of parts mounted thereon. Thus, accurate notification of a parts shortage can be effected.
Although the present invention has been fully described in connection with the preferred embodiments thereof with reference to the accompanying drawings, it is to be noted that various changes and modifications are apparent to those skilled in the art. Such changes and modifications are to be understood as included within the scope of the present invention as defined by the appended claims unless they depart therefrom.
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An electronic parts mounting method for taking out from a parts supply device having a plurality of electronic parts at least one of the electronic parts, and mounting the part at a predetermined position of a substrate to be manufactured, includes steps of storing quantity of parts, which is held by each parts supply device, in a storing section provided in each parts supply device, rewriting the quantity of parts according to number of parts taken out from the parts supply device by a calculating section provided in each parts supply device, reading out an initial value of the quantity of parts held by each parts supply device, by a control section provided in an electronic parts mounting machine, calculating one of the quantity of parts required for the substrate and period of time required for mounting the part on the substrate by a calculating section provided in the electronic parts mounting machine, and carrying out, in advance, a parts shortage advance notification in each parts supply device based on a result of the calculating step.
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CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of and priority to U.S. Provisional Application No. 61/529,437, filed Aug. 31, 2011, entitled VARIABLE SPEED DRIVE CONTROL SYSTEM AND METHOD, which is hereby incorporated by reference in its entirety.
BACKGROUND
[0002] The application generally relates to variable speed drives. The application relates more specifically to controlling the ratio of voltage to frequency output by a variable speed drive or variable frequency drive.
[0003] In a chiller system or other heating, ventilation, air conditioning or refrigeration (HVAC&R) system where the compressor is coupled with a variable frequency drive (VFD) or variable speed drive (VSD), the compressor motor is typically sized to operate at a particular voltage-to-frequency (V/f) ratio and a particular load point. Because the compressor in the actual system can operate during a variety of conditions, the motor is typically not operating at peak efficiency.
[0004] Therefore, what is needed is a variable speed drive or variable frequency drive that can vary the ratio of voltage to frequency to compensate for varying load conditions.
SUMMARY
[0005] The present invention is directed to a system having a compressor, a condenser, an expansion device and an evaporator connected in a closed refrigerant circuit. The system includes a motor connected to the compressor to power the compressor and a variable speed drive connected to the motor to power the motor. The variable speed drive is operable to provide a variable voltage to the motor and a variable frequency to the motor. The system also includes a control panel to control operation of the variable speed drive and one or more components of the system and a sensor to measure an operational parameter of the system. The sensor is operable to communicate the measured operational parameter to the control panel. The control panel is operable to execute a control algorithm to determine a voltage-to-frequency ratio to be output by the variable speed drive using the measured operational parameter, and the voltage-to-frequency ratio varies based on the measured operational parameter.
[0006] The present invention is also directed to a method for controlling a variable speed drive. The method includes measuring an operating parameter of an HVAC&R system and determining a voltage to frequency ratio to be output by a variable speed drive using the measured operational parameter. The variable speed drive powers a compressor motor of the HVAC&R system. The method also includes generating control instructions for the variable speed drive based on the determined voltage to frequency ratio and adjusting the output voltage to frequency ratio provided by the variable speed drive to the compressor motor with the generated control instructions.
[0007] In the present application, the VFD or VSD can vary the V/f supplied to the motor to make the motor stronger or weaker to compensate for the varying conditions in an HVAC&R system. The VFD or VSD and corresponding controls can monitor the motor's power consumption (kW) absorbed by the motor and then raise or lower the V/f of the VFD or VSD to obtain the lowest possible power consumption from the motor.
[0008] One advantage of the present application is lower power consumption by the compressor motor which leads to energy savings.
[0009] Another advantage of the present application is the ability to correspond the ratio of voltage to frequency provided to the compressor motor based on the load conditions on the compressor. The correspondence of the ratio of voltage to frequency to the load conditions enables the compressor motor to operate at peak efficiency and thereby reduce power consumption.
[0010] Other features and advantages of the present invention will be apparent from the following, more detailed description of the preferred embodiments, taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 shows an exemplary embodiment for a heating, ventilation and air conditioning system.
[0012] FIG. 2 shows an isometric view of an exemplary vapor compression system.
[0013] FIGS. 3 and 4 schematically show exemplary embodiments of a vapor compression system.
[0014] FIG. 5 schematically shows an exemplary embodiment of a variable speed drive.
[0015] FIGS. 6-11 show charts of motor temperature and compressor efficiency versus frequency for different V/f ratios used in an exemplary HVAC&R system.
[0016] FIG. 12 shows a chart of motor temperature versus frequency for the different V/f ratios from FIGS. 6-11 .
[0017] FIG. 13 shows a chart of compressor efficiency versus frequency for the different V/f ratios from FIGS. 6-11 .
[0018] FIG. 14 shows a chart of peak sound levels versus frequency for different V/f ratios used in an exemplary HVAC&R system.
[0019] FIG. 15 shows an enlarged portion of the chart of FIG. 14 .
[0020] FIG. 16 shows an exemplary embodiment of a process for adjusting the V/f ratio of a variable speed drive.
[0021] Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0022] FIG. 1 shows an exemplary environment for a heating, ventilation and air conditioning (HVAC) system 10 in a building 12 for a typical commercial setting. The system 10 can include a vapor compression system 14 that can supply a chilled liquid which may be used to cool the building 12 . The system 10 can include a boiler 16 to supply heated liquid that may be used to heat the building 12 and an air distribution system which circulates air through the building 12 . The air distribution system can also include an air return duct 18 , an air supply duct 20 and an air handler 22 . The air handler 22 can include a heat exchanger that is connected to the boiler 16 and vapor compression system 14 by conduits 24 . The heat exchanger in the air handler 22 may receive either heated liquid from the boiler 16 or chilled liquid from the vapor compression system 14 , depending on the mode of operation of the system 10 . The system 10 is shown with a separate air handler on each floor of the building 12 , but it is appreciated that the components may be shared between or among floors.
[0023] FIGS. 2 and 3 show an exemplary vapor compression system 14 that can be used in an HVAC system 10 . The vapor compression system 14 can circulate a refrigerant through a circuit starting with a compressor 32 and including a condenser 34 , expansion valve(s) or device(s) 36 , and an evaporator or liquid chiller 38 . The vapor compression system 14 can also include a control panel 40 that can include an analog to digital (A/D) converter 42 , a microprocessor 44 , a non-volatile memory 46 , and an interface board 48 . Some examples of fluids that may be used as refrigerants in the vapor compression system 14 are hydrofluorocarbon (HFC) based refrigerants, for example, R-410A, R-407, R-134a, hydrofluoro olefin (HFO), “natural” refrigerants like ammonia (NH 3 ), R-717, carbon dioxide (CO 2 ), R-744, or hydrocarbon based refrigerants, water vapor or any other suitable type of refrigerant. In an exemplary embodiment, the vapor compression system 14 may use one or more of each of variable speed drive (VSD) 52 , motor 50 , compressor 32 , condenser 34 , expansion valve 36 and/or evaporator 38 in one or more refrigerant circuits.
[0024] The motor 50 used with the compressor 32 can be powered by a VSD 52 . The VSD 52 receives AC power having a particular fixed line voltage and fixed line frequency from the AC power source and provides power having a variable voltage and frequency to the motor 50 . The motor 50 can include any type of electric motor that can be powered by a VSD. The motor 50 can be any suitable motor type, for example, a switched reluctance motor, an induction motor, or an electronically commutated permanent magnet motor.
[0025] The compressor 32 compresses a refrigerant vapor and delivers the vapor to the condenser 34 through a discharge passage. The compressor 32 can be a screw compressor in one exemplary embodiment. However, the compressor 32 can be any suitable type of positive displacement compressor or a centrifugal compressor. The refrigerant vapor delivered by the compressor 32 to the condenser 34 transfers heat to a fluid, for example, water or air. The refrigerant vapor condenses to a refrigerant liquid in the condenser 34 as a result of the heat transfer with the fluid. The liquid refrigerant from the condenser 34 flows through the expansion device 36 to the evaporator 38 . In the exemplary embodiment shown in FIG. 3 , the condenser 34 is water cooled and includes a tube bundle 54 connected to a cooling tower 56 .
[0026] The liquid refrigerant delivered to the evaporator 38 absorbs heat from another fluid, which may or may not be the same type of fluid used for the condenser 34 , and undergoes a phase change to a refrigerant vapor. In the exemplary embodiment shown in FIG. 3 , the evaporator 38 includes a tube bundle having a supply line 60 S and a return line 60 R connected to a cooling load 62 . A process fluid, for example, water, ethylene glycol, calcium chloride brine, sodium chloride brine, or any other suitable liquid, enters the evaporator 38 via the return line 60 R and exits the evaporator 38 via the supply line 60 S. The evaporator 38 lowers the temperature of the process fluid in the tubes. The tube bundle in the evaporator 38 can include a plurality of tubes and a plurality of tube bundles. The vapor refrigerant exits the evaporator 38 and returns to the compressor 32 by a suction line to complete the cycle.
[0027] FIG. 4 , which is similar to FIG. 3 , shows the vapor compression system 14 with an intermediate circuit 64 incorporated between the condenser 34 and the expansion device 36 . The intermediate circuit 64 has an inlet line 68 that can be either connected directly to or can be in fluid communication with the condenser 34 . As shown, the inlet line 68 includes an expansion device 66 positioned upstream of an intermediate vessel 70 . The intermediate vessel 70 can be a flash tank, also referred to as a flash intercooler, in an exemplary embodiment. In an alternate exemplary embodiment, the intermediate vessel 70 can be configured as a heat exchanger or a “surface economizer.” In the configuration shown in FIG. 4 , the intermediate vessel 70 is a flash tank and the expansion device 66 operates to lower the pressure of the liquid received from the condenser 34 . During the expansion process, a portion of the liquid vaporizes. The intermediate vessel 70 may be used to separate the vapor from the liquid received from the expansion device 66 and may also permit further expansion of the liquid. The vapor may be drawn by the compressor 32 from the intermediate vessel 70 through a line 74 to the suction inlet, a port at a pressure intermediate between suction and discharge or an intermediate stage of compression. The liquid that collects in the intermediate vessel 70 is at a lower enthalpy from the expansion process. The liquid from the intermediate vessel 70 flows in a line 72 through a second expansion device 36 to the evaporator 38 .
[0028] In an exemplary embodiment, a compressor 32 can include a compressor housing that contains the working parts of the compressor 32 . Vapor from the evaporator 38 can be directed to an intake passage of the compressor 32 . The compressor 32 compresses the vapor with a compression mechanism and delivers the compressed vapor to the condenser 34 through a discharge passage. The motor 50 may be connected to the compression mechanism of the compressor 32 by a drive shaft.
[0029] Vapor flows from the intake passage of a positive displacement compressor 32 and enters a compression pocket of the compression mechanism. The compression pocket is reduced in size by the operation of the compression mechanism to compress the vapor. The compressed vapor can be discharged into the discharge passage. For example, for a screw compressor, the compression pocket is defined between the surfaces of the rotors of the compressor. As the rotors of the compressor engage one another, the compression pockets between the rotors of the compressor, also referred to as lobes, are reduced in size and are axially displaced to a discharge side of the compressor.
[0030] FIG. 5 shows an exemplary embodiment of a VSD. The VSD 52 receives AC power having a particular fixed line voltage and fixed line frequency from an AC power source and provides AC power to a motor 50 at a desired voltage and desired frequency, both of which can be varied to satisfy particular requirements. The VSD 52 can have three components: a rectifier/converter 222 , a DC link 224 and an inverter 226 . The rectifier/converter 222 converts the fixed frequency, fixed magnitude AC voltage from the AC power source into DC voltage. The DC link 224 filters the DC power from the converter 222 and provides energy storage components such as capacitors and/or inductors. Finally, the inverter 226 converts the DC voltage from the DC link 224 into variable frequency, variable magnitude AC voltage for the motor 50 .
[0031] In an exemplary embodiment, the rectifier/converter 222 may be a three-phase pulse width modulated boost rectifier having insulated gate bipolar transistors to provide a boosted DC voltage to the DC link 224 to obtain a maximum RMS output voltage from the VSD 52 greater than the input voltage to the VSD 52 . Alternately, the converter 222 may be a passive diode or thyristor rectifier without voltage-boosting capability.
[0032] The VSD 52 can provide a variable magnitude output voltage and a variable frequency to the motor 50 , to permit effective operation of the motor 50 in response to particular load conditions. The control panel 40 can provide control signals to the VSD 52 to operate the VSD 52 and the motor 50 at appropriate operational settings for the particular sensor readings received by the control panel 40 . For example, the control panel 40 can provide control signals to the VSD 52 to adjust the output voltage and output frequency provided by the VSD 52 in response to changing conditions in the vapor compression system 14 . In one exemplary embodiment, the control panel 40 can provide instructions to increase or decrease the output voltage and output frequency, while maintaining the same V/f ratio, provided by the VSD 52 in response to increasing or decreasing load conditions on the compressor 32 .
[0033] However, in another exemplary embodiment, the control panel 40 can individually increase or decrease the output voltage and/or the output frequency from the VSD 52 to obtain different V/f ratios from the VSD 52 . In one exemplary embodiment, the control panel can adjust the V/f ratio based on the motor's power consumption (kW). However, in other embodiments, different operating parameters (e.g., compressor discharge temperature or motor temperature), can be used in addition to or instead of the motor's power consumption. The control panel can select the appropriate V/f ratio for the VSD from one or more look-up tables based the current or measured operating conditions or parameters of the motor and/or system. The look-up tables can be generated as part of the system start-up process (either at the factory or at the site) and involves operating the system at varying conditions to determine the optimal V/f ratio for particular conditions. In another embodiment, the control panel can determine an operating frequency for the VSD using a capacity control algorithm with the current or measured operating conditions or parameters of the motor and/or system as an input and then select the appropriate voltage corresponding to that operating frequency from the capacity control algorithm that provides maximum efficiency. In yet another embodiment, the control panel can control the VSD to iteratively cycle through various V/f ratios and select the one that provides the best efficiency. In still another embodiment, the V/f ratio can be calculated from a control algorithm, such as a fuzzy logic algorithm, based on the measured operating conditions or parameters of the motor and/or system.
[0034] FIG. 16 shows an exemplary embodiment of a control process executed by the control panel to vary the V/f ratio of a VSD. The process begins by measuring one or more operating parameters from the HVAC&R system (step 302 ). In one embodiment, the measured operating parameter can be the motor's power consumption (kW). However, in other embodiments, different operating parameters, e.g., compressor discharge temperature, motor temperature or motor current, can be used in addition to or instead of the motor's power consumption. Next, a V/f ratio for the VSD is determined from the measured operating parameter (step 304 ). In one embodiment, the determined V/f ratio can be determined from one or more tables that correspond the measured operating parameters to V/f ratios. In other embodiments, one or more control algorithms can be used to determine or calculate the V/f ratio using the measured operating parameter or other preselected parameters. Once the V/f ratio for the VSD has been determined, the control panel can generate control instructions for the VSD to implement the determined V/f ratio (step 306 ). The output of the VSD is then adjusted using the control instructions to provide the determined V/f ratio to the compressor motor (step 308 ). The process then returns to the start to repeat the process.
[0035] For FIGS. 6-13 , an HVAC system was operated at different V/f ratios. The HVAC system used R-134a refrigerant, and operated at a condenser temperature of about 100° Fahrenheit (F) and an evaporator temperature of about 40° F. In each of FIGS. 6-11 , the compressor (adiabatic) efficiency, i.e., the ratio of the theoretical power consumption for the compressor to the actual power consumption (W theo /W actual ), is shown for a range of frequencies and a particular V/f ratio. In addition, a temperature of the compressor motor is shown for the same range of frequencies and particular V/f ratio.
[0036] In another embodiment, the V/f ratio can be varied for sound attenuation purposes since noise can be generated by vibrations within the motor. As shown in FIGS. 14 and 15 , different V/f ratios produce different peak noise levels in the compressor and an optimum V/f can be selected to reduce noise levels in the compressor. In FIGS. 14 and 15 , the “Poly” lines represent trend data for the corresponding voltage identified. The optimum V/f can be selected in a manner similar to that previously described for motor/system efficiency and can be dependent upon the selected motor and the applied load.
[0037] It is important to note that the construction and arrangement of the present application as shown in the various exemplary embodiments is illustrative only. Although only a few embodiments have been described in detail in this application, those who review this application will readily appreciate that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters (e.g., temperatures, pressures, etc.), mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter described in the application. For example, elements shown as integrally formed may be constructed of multiple parts or elements, the position of elements may be reversed or otherwise varied, and the nature or number of discrete elements or positions may be altered or varied. Accordingly, all such modifications are intended to be included within the scope of the present application. The order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments. In the claims, any means-plus-function clause is intended to cover the structures described herein as performing the recited function and not only structural equivalents but also equivalent structures. Other substitutions, modifications, changes and omissions may be made in the design, operating conditions and arrangement of the exemplary embodiments without departing from the scope of the present application. Accordingly, the present application is not limited to a particular embodiment, but extends to various modifications that nevertheless fall within the scope of the appended claims.
[0038] Furthermore, in an effort to provide a concise description of the exemplary embodiments, all features of an actual implementation may not have been described (i.e., those unrelated to the presently contemplated best mode of carrying out the invention, or those unrelated to enabling the invention). It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation specific decisions may be made. Such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure, without undue experimentation.
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A variable speed drive (VSD) can be used to vary the voltage-to-frequency ratio (V/f) supplied to a compressor motor of a heating, ventilation, air conditioning or refrigeration (HVAC&R) system to make the motor stronger or weaker to compensate for varying conditions in the HVAC&R system. The VSD and corresponding control system or algorithm can monitor an operating parameter of the HVAC&R system, such as the kW absorbed by the motor, and then raise or lower the V/f of the VSD to obtain the lowest possible power consumption from the motor.
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This application claims the benefit of Ser. No. 60/145,972, filed Jul. 29, 1999.
FIELD OF THE INVENTION
This invention relates generally to a process and apparatus for the disposal of biological waste which includes, but is not limited to, medical waste, infectious waste, pathological waste, animal waste, and sanitary waste and henceforth referred to as biological waste.
BACKGROUND OF THE INVENTION
The cost of disposing of biological waste in the U.S. is more than $5 billion per year. The capital cost of the equipment required is in the hundreds of millions of dollars. All institutions and businesses that generate and handle this category of waste have needs to provide safe effective and inexpensive disposal of the waste. In recent years there has been increasing concern over the disposal of biological waste. The two principal methodologies for the disposal of this waste are incineration and dumping in landfills.
The Environmental Protection Agency (EPA) has issued new regulations that require incinerators to reduce their emissions to very stringent levels for products that are exhausted from biological waste incinerators. The new regulations will, for practical purposes, close down or require major modifications to almost all such incinerators by the year 2001. Municipal landfills have already begun to refuse to accept biological waste especially if it is identifiable as medical waste. Most alternatives to these two methods involve thermal methods that emit products into the atmosphere that are not acceptable.
Biological waste is defined as any waste that is considered by any of, but not limited to, the following statutes and regulations:
New Jersey State Statute, “Comprehensive Regulatory Medical Waste Management Act”, P.L. 1989, c. 34 (C.13.1E-48.13).
New York State Environmental Conservation Law, TITLE 15, “STORAGE, TREATMENT, DISPOSAL AND TRANSPORTATION OF REGULATED MEDICAL WASTE”, Section 27-1501. Definitions.
New York State Public Health Law, TITLE XIII, “STORAGE, TREATMENT AND DISPOSAL OF REGULATED MEDICAL WASTE”, Section 1389-aa. Definitions.
CALIFORNIA HEALTH AND SAFETY CODE, SECTION 117635. “Biohazardous Waste ” Title 25 Health Services, Part I.
Texas Department of Health, Chapter 1 Texas Board of Health, “Definition, Treatment, and Disposition of Special Waste from Health Care-Related Facilities, Section 1.132 Definitions.
40 C.F.R. 60.51(c) PROTECTION OF ENVIRONMENT; Standards of performance for new stationary sources.
40 C.F.R. 240.101 PROTECTION OF ENVIRONMENT; Guidelines for the thermal processing of solid wastes (Section P only).
49 C.F.R. 173.134 TRANSPORTATION; Class 6, Division 6.2-Definitions, exceptions and packing group assignments.
33 C.F.R. 151.05 TITLE 33-“NAVIGATION AND NAVIGABLE WATERS; VESSELS CARRYING OIL, NOXIOUS LIQUID SUBSTANCES, GARBAGE, MUNICIPAL OR COMMERCIAL WASTE, AND BALLAST WATER”;
Definitions (medical waste only).
Biological waste is a relatively new problem for today's technological society. The definition of this waste has been expanding in its coverage of materials that must be handled in a controlled manner. The foregoing list of state statutes and United States federal regulations are overlapping but necessary to accurately define the materials because no single statute or regulation covers all the materials to which this invention applies.
Mediated Electrochemical Oxidation (MEO) processes represent a mature science in the industrial complex over the past two decades. The orientation to date has been focused on the dissolution of transuranic metals and destruction of organics in mixed waste from the chemical reprocessing of irradiated nuclear reactor fuel, and controlled oxidation and destruction of organic-based military munitions and organophosphorus chemical weapon nerve agents, as is represented by patents dating back into the mid-eighties.
Research into the application of the MEO process to date has involved the use of the process to dispose of materials in these areas. In the first area, the MEO uses an electrochemical cell in which the electrolyte is generally restricted to a composition of nitric acid and silver ions. The silver ion serves as the regenerable mediating oxidizing species which is used in a oxidative dissolution of plutonium dioxide to recover plutonium contained in solid waste from processes, technological and laboratory waste (U.S. Pat. No. 4,749,519), and subsequently extended to the dissolution of the plutonium dioxide component of mixed oxide fuel (coprecipitated uranium and plutonium oxide) (U.S. Pat. No. 5,745,835).
In the second area, the MEO process was used: (a) for the decomposition (i.e. oxidation) of organic matter contained in the mixed solid waste generated in extracting plutonium from irradiated nuclear reactor fuel (U.S. Pat. Nos. 4,874,485; 4,925,643); (b) controlled oxidation of organic military munitions (U.S. Pat. No. 5,810,995); and (c) destruction of organophosphorus nerve agents (U.S. Pat. No. 5,855,763).
Both of the two areas discussed have involved similar use of the MEO process using nitric acid and silver ions being generated by an electrochemical cell with the anode and cathode being separated by a membrane. The two uses have differed in the temperature range used in each of the applications. The second use is operated between 50° C. and slightly below 100° C. to take advantage of the generation of the secondary oxidation species to assist in oxidizing organic materials. The first use is operated below 50° C. (generally around 25° C. or room temperature) to minimize Ag(II)—water reactions because unlike the Ag(II) ion, not all of the secondary oxidizing species have an oxidation potential sufficient to oxidize plutonium dioxide to a soluble species.
Others have substituted cerium and nitric acid, cobalt and nitric acid, and cobalt and sulfuric acid for the silver and nitric acid as the electrolyte (U.S. Pat. Nos. 5,516,972; 5,756,874). The temperatures vary among the three electrolytes being substituted for the silver and nitric acid combination. Most recently, ruthenium in a nearly neutral solution has been proposed as the electrolyte in a MEO process to decompose organic materials, which would operate between 50° C. and 90° C. (Platinum Review, Jul. 1998). All of the descriptions reviewed are similar in their application to the decomposition of organic materials and differ in their choice of electrolyte(s), pH, concentrations, and the operating temperature range over which they are applied.
These and other objects and features of the invention are apparent in the disclosure, which includes the above and ongoing written specification, with the drawings.
SUMMARY OF THE INVENTION
The invention relates to a method and apparatus for the mediated electrochemical oxidation (MEO) of wastes, such as biological materials and has particular application to, but is not limited to, biological waste, medical waste, infectious waste, pathological waste, animal waste, and sanitary waste (henceforth collectively referred to as biological waste).
A mediated electrochemical oxidation process involves an oxidizing electrolyte, wherein at least one oxidizing species is electrochemically generated in an electrochemical cell. A membrane in th e electrochemical cell separates the anolyte and catholyte. The preferred MEO process uses as mediator ions, for example, the following metals: Ag, Ce, Co, Fe, Mn or Ru in nitric acid, sulfuric acid or phosphoric acid as the anolyte. A cost reduction can be achieved in the a basic MEO process by using anions that are useable in alkaline solutions such as NaOH and KOH, since the oxidation potentials usually decrease with increasing pH. The catholyte may contain the same acid as the anolyte, but not necessarily in the same concentration. The process operates over the temperature range from room temperature up to a temperature slightly below the boiling point of the electrolyte solution (usually the temperature will be below 100° C.) during the destruction of the biological waste.
The MEO process begins with the electrochemical oxidation of the dissolved mediator ions to one of their higher valence states, after which these ions oxidize the biological waste and are themselves reduced down to their initial lower valence state, whereupon they are again electrochemically oxidized back up to their higher valence state. In the case of some higher valence oxidized species, a second oxidation process is possible.
At higher temperatures (i.e., above about 50° C.) these higher valence oxidizer species react with the aqueous solution to produce a variety of powerful oxidizing free radicals (e.g., .OH, etc.) and hydrogen peroxide, etc. Decomposition of the hydrogen peroxide into free hydroxyl radicals is well known to be promoted by ultraviolet irradiation. The MEO process biological waste destruction rate using these species, therefore, will be increased by ultraviolet irradiation of the reaction chamber anolyte.
The principals of the oxidation process in which the hydroxyl free radical cleaves chemical bonds and oxidizes organic compounds have been widely documented, resulting in the formation of successively smaller chained hydrocarbon compounds. The intermediate compounds formed are easily oxidized to carbon dioxide and water during sequential reactions.
One distinction between the prior art and this invention is in the application to biological waste, which distinctly differs from all prior applications. The prior art processes and their supporting patents may focus on organic materials, but they clearly distinguish from biological waste both in describing their processes and specifically in the examples of materials being treated by their processes. The materials are generally characterized as complex organic molecules associated with industrial processes. The prior art does not describe or refer to a single process that is biological in nature. Prior art processes that specifically deal with biological waste do not use the MEO process to dispose of those categories of waste.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic representation of a system for destroying biological waste materials.
FIG. 2 is a schematic representation of the preferred embodiment.
FIG. 3 is a schematic representation of the steps of the process used in the apparatus.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
MEO Chemistry
Mediated Electrochemical Oxidation (MEO) process chemistry described in this patent uses one or more of the following metallic ions: silver, cerium, cobalt, iron, manganese and ruthenium in the anolyte as the mediator. The catholyte is composed of one of the following acids; nitric, sulfuric, or phosphoric.
The MEO Apparatus is unique in that it accommodates the numerous choices of mediator metallic ions and acids by draining, flushing, and refilling the system with the electrolyte of choice.
Because of redundancy and similarity in the description of the various metallic ions, only the iron and nitric acid combination is discussed in detail. The Fe (VI) ion (i.e. FeO 4 −2 species) has an oxidation potential sufficient to react with water to produce secondary oxidation species (e.g., hydroxyl free radicals, etc.). The remainder of this discussion addresses the more complex Fe (VI) process as it not only addresses the oxidation due to the metal ions but also the secondary oxidation species.
FIG. 1 shows an MEO Apparatus in a schematic representation of the system for destroying biological waste. At the anode of the electrochemical cell 17 Fe (III) ions (Fe 30 3 , ferric) are oxidized to Ag Fe (VI) ions (FeO 4 −2 , ferrate),
Fe −3 +4H 2 O→FeO 4 −2 −8H − +3c −
the anolyte temperate is sufficiently high, typically above 50° C., the Fe (VI) species may undergo a redox reaction with the water in the aqueous anolyte. The oxidation of water proceeds by a sequence of reactions producing a variety of intermediate reaction products, some of which react with each other. A few of these intermediate reaction products are highly reactive free radicals including, but not limited to the hydroxyl (.OH) and hydrogen peroxy (.HO 2 ) radicals. Additionally, the mediated oxidizer species ions may interact with the stated acid in the anolyte (HNO 3 , H 2 SO 4 , or H 3 PO 4 ) to produce free radicals typified by, but not limited to .NO 3 . Another possible source of free radicals from the electrolyte acids is the direct oxidation of the NO 3 − , SO 4 −2 , or PO 4 −3 ions at the anode of the cell. The population of hydroxyl free radicals may be increased by ultraviolet irradiation of the anolyte in the reaction chamber to cleave the hydrogen peroxide molecules, intermediate reaction products, into two such radicals.
These secondary oxidation species in conjunction with Fe (VI) ions oxidize the biological materials.
The oxidizers react with the biological waste to produce CO 2 and water. These processes occur in the anolyte on the anode side of the system in the reaction chamber 5 . Addition of iron ions to non-iron-based MEO systems are also proposed as this has the potential for increasing the overall rate of medical waste oxidation compared to the non-iron MEO system alone. The electrochemical oxidation proceeds much faster for iron ions than for most other mediator ions. Therefore, if the two step process of electrochemically forming an FeO 4 −2 ion and the FeO 4 −2 ion oxidizing the mediator ion to its higher valence occurs faster than the direct electrochemical oxidation of the mediator ion, then there is an overall increase in the rate of biological waste destruction.
Membrane M separates the anode and the cathode chambers in the electrochemical cell. Hydrogen ions (H + )travel through the membrane M due to the electrical potential from the power supply 21 applied between the electrodes 18 and 19 . In the catholyte the nitric acid is reduced to nitrous acid
3HNO 3 +6H + +6e − →3HNO 2 +3H 2 O
by the reaction between the H + ions and the nitric acid. Oxygen is introduced into the catholyte through the air sparge 35 , and the nitric acid is regenerated,
3HNO 2 +3/2O 2 →3HNO 3
The overall process results in the biological waste being converted to carbon dioxide, water, and a small amount of inorganic compounds in solution or as a precipitate.
The biological waste may be a liquid, solid, or a mixture of solids and liquids. The biological waste is introduced into the top of biological waste basket 3 in the reaction chamber 7 . The apparatus continuously circulates the anolyte portion of the electrolyte through the reaction chamber to promote maximum contact area between the waste and the oxidizing species. Contact of the oxidizing species with incomplete oxidation products that are gaseous at the conditions within the reaction chamber 5 may be enhanced by using conventional techniques for promoting gas/liquid contact 7 (e.g., ultrasonic vibration, mechanical mixing). All surfaces of the apparatus in contact with the anolyte or catholyte are composed of stainless steel or nonreactive polymers such as PTFE (Teflon™).
The anolyte circulation system contains a pump 9 and a removal and treatment system 12 (e.g., filter, centrifuge, hydrocyclone, settling tank, etc.) to remove any precipitate or other insoluble inorganic compounds that form as a result of mediator ions (e.g., Ag, Ce, Co, Fe, Mn, Ru) reacting with the small amount of chlorine (or other anions) that may be present in the waste stream. The anolyte is returned to the electrochemical cell 17 , which completes the circulation in the anode side (A).
Waste may be added to the basket 3 in the reaction chamber either continuously or in the batch mode. The anolyte starts either at the operating temperature or at a lower temperature, which subsequently is increased by the thermal control 7 to the desired operating temperature for the specific waste stream. Waste may also be introduced into the apparatus, with the concentration of electrochemically generated oxidizing species in the anolyte being limited to some predetermined value between zero and the maximum desired operating concentration for the waste stream by control of the electric current by the system power supply 23 supplied to the electrochemical cell 17 . The electrolyte is composed of an aqueous solution of mediator ions and acid (nitric, phosphoric, or sulfuric acid) and is operated over the temperature range from room temperature to slightly below the boiling point of the electrolytic solution (usually less than 100° C.).
Considerable attention has been paid to halogens and their interactions with silver ions, which are of much less importance to this invention. The biological waste contains relatively small amounts of these halogen elements compared to the halogenated solvents and nerve agents addressed in the cited patents. Silver ions are required to oxidize those organic compounds in the cited patents while in this patent there is a choice of mediator ions. The choice of mediator ions effects the cost of the electrolyte and may be used to avoid formation of insoluble inorganic compounds thereby preventing removal of the mediator.
The residue of the inorganic compounds is flushed out of the treatment system 12 during periodic maintenance if necessary. If desired inorganic compounds may be recovered from the process stream using any one of several chemical or electrochemical processes. The apparatus operates across the temperature range from room temperature to slightly below the boiling point of the electrolyte (generally below 100° C.) adjusted to the composition of the materials introduced in to the reaction chamber. The system is monitored for the production of CO 2 as a means of determining when the decomposition process is complete.
The entireties of U.S. Pat. Nos. 4,749,519; 4,874,485; 4,925,643; 5,745,935; 5,810,995; and 5,855,763 are included herein by reference for their relevant teachings.
MEO Apparatus
A schematic drawing of the MEO apparatus shown in FIG. 1 illustrates the application of the MEO process to the destruction of biological waste. The lid 1 is raised and the biological waste is placed or poured into the basket 3 in the reaction chamber 5 as liquid, solid, or a mixture of liquids and solids. A small thermal control unit is connected to the reaction chamber 5 to heat or cool the anolyte to the selected temperature range.
The anolyte portion of the electrolyte solution contains mediated oxidizer species and secondary oxidizing species. The anolyte is circulated into the reaction chamber from the electrochemical cell 17 by pump 9 . The anolyte portion and catholy te portion of the electrolyte are separated by a membrane M in the electrochemical cell 17 . The electrochemical cell 17 is powered by a DC power supply 21 typically delivering 2 to 6 volts. The DC power supply 21 operates off a typical 110 volt or 220 volt AC line.
The electrolyte containment boundary is composed of materials resistant to the oxidizing electrolyte (e.g., stainless steel, PTFE, PTFE lined stainless steel, etc.). Reaction products resulting from the oxidizing processes being conducted on the anolyte side (A) of the system that are gaseous at the anolyte operating temperature and pressure are discharged to the condenser 15 . The more easily condensed products of incomplete oxidation are separated from the off gas stream 16 and are returned to the anolyte reaction chamber for further oxidation. The noncondensible incomplete oxidation products (e.g., low molecular weight organics, carbon monoxide, etc.) are reduced to acceptable levels for atmospheric release by a gas cleaning system 15 .
Various scrubber/absorption columns are used or the gas mixture is recontacted with the anolyte to provide adequate reaction time and contact area to ensure the required degree of oxidation, if necessary. A major product of the oxidation process is CO 2 , which is vented 16 out of the system. An optional inorganic compound removal and treatment systems 13 is used should there be more than trace amount of chlorine, or other precipitate forming anions present in the biological waste being processed.
A pump 39 circulates the catholyte portion of the electrolyte through the portion of the electrochemical cell 17 on the cathode side of the membrane. The catholyte portion of the electrolyte flows into a catholyte reservoir 25 . A small thermal control unit 31 is connected to the catholyte reservoir 25 to heat or cool the catholyte to the selected temperature range. External air is introduced through an air sparge 35 into the catholyte reservoir 25 . The oxygen contained in the air oxidizes nitric acid and the small amounts of nitrogen oxides produced by the cathode reactions to nitric acid and NO 2 , respectively. Contact of th e oxidizing gas with nitrous acid may be enhanced by using conventional techniques for promoting gas/liquid contact by a mixer 33 (e.g., ultrasonic vibration, mechanical mixing, etc.). Systems using non-nitric acid catholytes may also require air sparging to dilute and remove off gas such as hydrogen. An off gas cleaning system 36 is used to remove any unwanted gas products (e.g. NO 2 , etc.). The cleaned gas stream, combined with the unreacted components of the air introduced into the system is discharged through the off gas vent 37 . Optional mediated oxidizer species recovery (i.e. metallic ions) and treatment system 20 is positioned on the catholyte side. Some mediated oxidizer species may cross the membrane M in small amounts, and this option is available if it is necessary to recover the species (i.e. metallic ions).
In a preferred embodiment shown in FIG. 2, System Model 1.0 is sized for use in a medical office or laboratory. Other systems are similar in nature but are scaled up in size to handle a larger capacity of waste, such as patient's room, operating room, laboratories, etc.
The system has a control keyboard 8 for input of commands and data. There is a monitor screen to display the systems operation and functions. Below these controls are the status lights 6 for on, off, and standby. Hinged lid 1 is opened and the biological waste is deposited in the basket 3 in the chamber 7 . A lid stop 2 keeps the lid opening controlled. In the chamber is the aqueous acid and mediated oxidizer species solution in which higher valence oxidizer species initially may be present or may be generated electrochemically after introduction of the waste and application of power 23 to the cell 17 . Power supply 21 provides direct current to an electrochemical cell 17 . Pump 9 circulates the anolyte portion of the electrolyte and the biological waste material is rapidly oxidized at room temperature and ambient pressure. The oxidation process will continue to break the materials down into less and less complex molecules until they reach CO 2 , water, and some trace inorganic salts. Any residue is passified in the form of a salt and may be periodically removed through the flush and drain outlets 11 . The electrolyte may be changed through this same plumbing. The catholyte reservoir has two flange joints 27 and 29 , which allow access to the reservoir for cleaning.
Due to low power consumption and low consumption of mediated oxidizer species and electrolyte acid the device may remain activated throughout the day, and biological waste may be added as it is generated. The compactness of the device makes it ideal for offices and surgeries as well as suitable for use with high volume inputs of laboratories and hospitals. The process operates at low temperature and ambient atmospheric pressure and does not generate toxic compounds during the destruction of the biological waste, making the process indoor compatible. The system is scalable to a unit large enough to replace a hospital incinerator system. The CO 2 oxidation product is vented out the wall vent 16 , and the atmospheric air vent 37 for the cathode side is shown.
Steps of the Operation of the MEO Process
FIG. 3 is a schematic of the steps in the operation of process of destroying biological waste in the System Model 1.0. The system is started 43 by engaging the “On” button on the control keyboard 8 . The monitor screen 10 displays the steps of the process in the proper sequence. The lid 1 is opened and the biological waste is placed 45 in the basket. The thermal controls 7 and 31 are turned on 47 / 61 , which brings the electrolyte in to the temperature range for proper function. The electrochemical cell is energized 49 , 63 . The pumps 9 and 39 begin to circulate 51 , 65 the anolyte and catholyte respectively.
As soon as the electrolyte circulation is flowing throughout the system, the mixers begin to operate 53 and 67 . The biological waste is being decomposed into water and CO 2 , which is discharged 55 out of the Co 2 vent 16 . Air is drawn 69 into the catholyte reservoir 25 , and excess air is discharged 70 out the atmospheric vent 37 . When the CO 2 production ceases, the biological waste has been fully destroyed 57 , and the system goes to standby 59 .
EXAMPLE
Example (1)
The device performance parameters may be estimated for medical/pathological waste by analyzing the electrochemical oxidation of human protoplasm, stated in the literature to consist of 67 weight % water, 29 weight % organic solids and 4 weight % minerals. These organic solids are composed of proteins (15 weight %), lipids (13 weight %) and carbohydrates (1 weight %). For this analysis it is assumed the protein is collagen (C 102 H 149 O 38 N 31 ), the lipids, or fats (C 57 H 110 O 6 ) and the carbohydrates are glucose units (C 6 H 12 O 6 ), and the oxidation products are H 2 O, CO 2 and NO 2 . Assuming a 3-volt cell potential and 100percent current efficiency, it requires 8.2 kWh to oxidize 1-kg human protoplasm. The time required may be determined by (1) the electrode surface area of the cell (i.e., 0.5 amp/cm 2 current density limit) and (2) the capacity of the power supply at 3 volts.
Anolyte is in the range of 1 to 22 M nitric acid, typically about 4 to 8M nitric acid, 0.01 to a saturated solution of a soluble iron (ferric) typically 0.5M soluble iron ferric salt (usually but not limited to ferric nitrate). If augmented by the addition of a soluble Ag, Ce, Co, Mn, or Ru salt in the range 0.1 to a saturated solution, the lower limit of the soluble iron salt concentration may be reduced to 0.001 M. Catholyte is in the range of 1 to 22 M nitric acid, typically about 4 to 8M nitric acid. The apparatus is operated between room temperature and slightly below the boiling point. In the alternative acids case the range of 1-19 M sulfuric and phosphoric acids for mediators soluble in them in the same concentration ranges for Fe +3 .
Example (2)
The MEO process produces CO 2 , water, and trace inorganic salts, all of which are considered benign for introduction into the environment by regulatory agencies. The cost of using the MEO process in this invention is competitive with both the incineration and landfill methodologies. The MEO process is uniquely suited for destruction of biological waste because water, which constitutes a major portion of this waste (e.g., tissue, bodies fluids, etc.) is actually a source of secondary oxidizing species rather than parasitic reactions competing for the mediator oxidizer specie s. Furthermore, the energy that must be provided in the MEO process to heat the waste stream water component from ambient to the electrolyte operating temperature (i.e., 80° C. maximum temperature increase) is trivial compared to the water enthalpy increase required in autoclave or incineration based processes.
Example (3)
The system is unique relative to earlier art, since it is built to operate in a hospital room or laboratory where it must be compatible with people working in close proximity to the system as well as next to people being treated for medical conditions.
Example (4)
The system is built to require limited skill to operate it. The system needs to be accessed during it s operating cycle so that more biological waste may be added and needs to remain compatible with the room environment.
Example (5)
The system is built to operate with materials that are safe to handle in the environment in which it is to be used. The biological waste contains little or no substances that react with our choice of electrolytes to produce volatile compounds that would offer a problem in the room environment. The system may operate at temperatures less then 100° C. and at ambient atmospheric pressure, which adds to the indoor compatibility.
Example (6)
The simplicity of the new system built for use with biological waste produces a system less expensive to operate and cleaner to use than existing waste treatments. The system complexity is reduced by comparison to previous MEO system, since there is not a requirement to deal with quantities of halogens. The system is truly a green machine' in the sense of an environmentally benign system.
Example (7)
The system is built so that the composition of the electrolyte may be changed to adapt the system to a selected composition of the biological waste stream.
Example (8)
The system flexibility provides for the introduction of more then one metallic ion resulting in marked improvement in the efficiency of the electrolyte. Furthermore, it desensitizes the electrolyte to chlorine ions in solution.
While the invention has been described with reference to specific embodiments, modifications and variations of the invention may be constructed without departing from the scope of the invention.
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A mediated electrochemical oxidation process is used to treat, oxidize and dispose of biological waste materials. Waste materials are introduced into an apparatus for contacting the waste with an electrolyte, which comprises one or more oxidizing species in their higher valence states in aqueous solution. The electrolyte, which can be regenerated, is used to oxidize specific molecules of the waste materials, breaking them down and preventing the formation of dioxins. The waste treatment process takes place at a temperature range from room temperature up to a temperature slightly below the boiling point of the electrolyte solution (usually the temperature will be below 100° C.), and can be altered by adding ultraviolet radiation.
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This is a continuation of Ser. No. 049,567, filed 5/14/87, now abandoned.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an optical information recording and reproducing apparatus for recording information on an optical information recording medium, reproducing the information recorded on the medium and/or erasing the information recorded on the medium. Such an information recording and reproducing apparatus is suitably used as an information recording and reproducing apparatus which uses a card-like information recording medium on which a plurality of linear information tracks are arranged in parallel.
2. Related Background Art
As a medium for recording information by using a light and reading the information thus recorded, disk-shaped, card-shaped and tape-shaped media have been known. Of those, the card-shaped optical information recording medium (hereinafter referred to as an optical card) is compact and light in weight, convenient to carry and has a large memory capacity. Accordingly, a big demand is expected.
FIG. 1 shows a plan view of such an optical card 101. Numeral 102 denotes an information record area, numeral 103 denotes an information track, numerals 104 and 104' denote track select area, and numeral 105 denote a home position of a light beam spot.
On the optical card, information is recorded as a line of optically detectable record bits (information track) by scanning the card by a light beam which is modulated by recording information and focused into a small spot. In order to exactly record information without trouble such as crossing of information tracks, it is necessary to control (autotracking or AT) an irradiation position of the light beam spot on the optical card in a direction normal to a scan direction. In order to irradiate the light beam as a stable small spot irrespective of curvature of the optical card or mechanical tolerance, it is necessary to control (auto-focusing or AF) the light beam spot in a direction normal to the optical card surface. Further, the AT and AF are required in the reproduce mode.
FIG. 2 shows a configuration of an apparatus for recording and reproducing information to and from the optical card. Numeral 106 denotes a motor for driving the optical card 101 in a direction of arrow, numeral 107 denotes a light source such as a semiconductor laser, numeral 108 denotes a collimeter lens, numeral 109 denotes a beam splitter, numeral 110 denotes an objective lens, numeral 111 denotes a tracking coil, numeral 112 denotes a focusing coil, numerals 113 and 114 denote condenser lenses, numerals 115 and 116 denote photo-electric conversion elements, numeral 117 denotes a tracking control circuit and numeral 118 denotes a focusing control circuit. Currents are supplied to the tracking coil 111 and focusing coil 112 by commands from the control circuits 117 and 118 in accordance with tracking signal and focusing signal detected by the photo-electric conversion elements 115 and 116 so that the objective lens 110 is driven to effect the AT and AF.
A method for recording and reproducing information is explained with reference to FIGS. 1 and 2. The light beam spot is initially at the home position 105. The light beam spot them moves on the track select area 104 in a direction u to find a record or reproduce track N, when the AT and AF are effected and the N is scanned in a direction r to record or reproduce information. When the light beam spot comes into the track select area 104', a large current is momentarily supplied to the tracking coil 111 (FIG. 2) so that the light beam spot is kicked to the track (N+1). Then, the track (N+1) is scanned in the reverse direction l to record or reproduce information. Depending on amount of information, the scan of the information track 103 by the light beam spot and the kick of the light beam spot in the track select areas 104 and 104' are repeated several times.
In such an information recording and reproducing apparatus, when the optical card 101 is reciprocally driven by the motor 106, vibration is generated in the directions of AT and AF, because the light beam spot may be off-tracked in the direction of AT from the information track due to skew of the information track relative to the contour of the optical card and a backlash of the optical card drive mechanism and the AT control attempts to compensate for such off-track. On the other hand, in the direction of AF, the light beam spot may be defocused from the record plane of the optical card due to curvature of the optical card and the backlash of the optical card drive mechanism, and the AF control attempts to compensate it.
It has been known that the amplitude of such vibration depends on a frequency. FIG. 3 illustrates such frequency dependency. It shows the dependency in the AT direction. It is assumed that the skew is ±100 μm. Assuming that the vibration in the AT direction is generated merely by the skew, the frequency dependency of the amplitude of the vibration in the AT direction is represented by a, at a frequency up to a reciprocation frequency fs when the light beam spot scans, the amplitude is flat at 100 μm, and above the frequency fs, the amplitude decreases at a rate of -12 dB/oct. In order to keep the deviation in the AT within ±0.1 μm, an open loop gain G T of the AT servo at the frequency below the scan frequency ts is
G.sub.T =20 log (100/0.1)=60 dB
as shown by α in FIG. 3, and it decreases at the rate of -12 dB/oct at the frequency above the scan frequency.
However, the vibration in the AT direction is caused not only by the skew but also by the reversal of the reciprocal movement of the optical card. Such vibration occurs at a resonant frequency fp (fs<fp). This is due to mechanical vibration of the drive mechanism by abrupt deceleration and abrupt opposite acceleration upon the reversal of the reciprocal movement of the optical card. The vibration in the AT direction including the vibration at the reversal is represented by b in FIG. 3. In order to keep the deviation of AT within ±0.1 μm under the vibration at the reversal, the AT gain is raised as shown by β in FIG. 3.
As a result, the AT is sufficiently attained at the reversal. However, at a time other than the reversal, the AT gain is higher than required, particularly in a high frequency band. Accordingly, the AT servo system is sensitive to a fine defect or dust on the surface of the optical card. This causes degradation of recorded or reproduced signal.
The same is true for the AF direction.
In the information recording and reproducing apparatus described above, the scan speed of the light beam spot in the γ direction and l direction differs between the record mode and the reproduce mode. In the record mode, a relatively low scan speed is selected by the limitation such as record sensitivity of the record medium. Thus, the speed V W in the record mode is lower than a speed V R in the reproduce mode (V W <V R ). Since the scan distance in the record mode is equal to the scan distance in the reproduce mode, a frequency f w of the reciprocation in the scan in the record mode is lower than a scan frequency f R in the reproduce mode (f W <f R ).
On the other hand, in the information recording and reproducing apparatus described above, when the optical card 101 is reciprocally driven by the motor 106, vibrations are generated in the AT and AF directions. It has been known that the amplitude of the vibration depends on the frequency of the vibration. FIG. 4 illustrates such frequency dependency. It shows the dependency in the AT direction. It is assumed that a recording scan frequency f W is 0.5 Hz, a reproducing scan frequency f R is 2.5 Hz and a skew is ±100 μm. Assuming that the vibration in the AT direction is generated merely by the skew, the frequency dependency of the amplitude of the vibration in the AT direction in the record mode is represented by c. The amplitude is flat at 100 μm at a frequency up to the recording scan frequency 0.5 Hz, and it decreases at a rate of -12 dB/oct at a frequency above the scan frequency. On the other hand, the frequency dependency of the amplitude in the AT direction in the reproduce mode is represented by d. The amplitude is flat at 100 μm at a frequency up to the reproducing scan frequency 2.5 Hz, and it decreases at a rate of -12 dB/oct at a frequency above the scan frequency.
In order to keep the deviation of AT within ±0.1 μm in both the record mode and the reproduce mode, the open loop gain G T of the AT servo is set as shown by α in FIG. 4. Namely, at a frequency below the reproducing scan frequency 2.5 Hz,
G.sub.T =20 log (100/0.1)=60 dB
and it decreases at a rate of -12 dB/oct at a frequency above the scan frequency.
As a result, sufficient AT control is effected in both the record mode and the reproduce mode. However, in the record mode, since the AT gain in a high frequency band is higher than required, the AT servo system is sensitive to a fine defect or dust on the surface of the optical card. This causes degradation of a recorded signal.
The same applies to the AF direction.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an optical information recording and reproducing apparatus which resolves the problems encountered in the prior art apparatus, does not cause degradation of recorded and reproduced signals by the affect of defect or dust on the surface of the recording medium, does not cause off-AT or off-AF, and improves reliability and an error rate.
In order to achieve the above object, in accordance with the present invention, a light beam spot is reciprocally moved relative to an information track on the optical information recording medium while it is tracked and/or focused to record information on the recording medium, reproduce the information recorded on the recording medium and/or erase the information recorded on the recording medium. The direction and/or speed of the reciprocal movement are switched, and the tracking servo gain and/or focusing servo gain are switched by control means.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a plan view of an optical card,
FIG. 2 shows a configuration of a prior art optical card recording and reproducing apparatus,
FIGS. 3, 4, 7, 9, and 10 show graphs of amplitudes of vibration in AT direction and AT servo gains,
FIG. 5 shows a configuration of an optical card recording and reproducing apparatus of the present invention,
FIG. 6 shows a signal time chart, and
FIG. 8 shows another embodiment of the optical card recording and reproducing apparatus of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 5 shows a configuration of an optical card recording and reproducing apparatus which is the optical information recording and reproducing apparatus of the present invention. The like elements to those shown in FIG. 2 are designated by the like numerals, and the explanation thereof is omitted.
In FIG. 5, numerals 121 and 122 denote a tracking control circuit and a focusing control circuit, respectively. In the tracking control circuit 121, numeral 121-1 denotes an amplifier which amplifies an electrical tracking signal supplied from a photoelectric conversion element 115 to an appropriate voltage Numeral 121-2 denotes an analog switch. Signal is supplied from the amplifier 121-1 through terminals C and D. Numeral 121-3 denotes a driver which receives the signal from the analog switch 121-2 to supply a drive signal current to a tracking coil 111. In the focusing control circuit 122, numeral 122-1 denotes an amplifier which amplifies an electrical focusing signal supplied from a photo-electric conversion element 116 to an appropriate voltage. Numeral 122-2 denotes an analog switch. The signal from the amplifier 122-1 is supplied thereto through terminals A and B. Numeral 122-3 denotes a driver which receives the signal from the analog switch 122-2 to supply a drive signal current to the focusing coil 112.
In FIG. 5, numeral 123 denotes a system controller which controls the recording and reproducing apparatus, and numeral 124 denotes a signal produced by the controller to control the direction of movement of the optical card (i.e., the direction of rotation of a motor 106). The controller 123 also produces other signals than 124 although they are not shown. Numeral 125 denotes a motor driver which receives the signal 124 to control the direction of rotation of the motor 106. Numeral 126 denotes a one-shot multivibrator which receives the signal 124 to produce a signal 127 when the signal 124 transits. FIG. 6 shows a time chart showing a relation between the signals 124 and 127. When the signal 124 changes from an L level to an H level and from the H level to the L level, pulse signals 127 having a width t are produced. In FIGS. 5 and 6, l and γ represent the directions of movement of the optical card 101 by the motor 106 in accordance with the signal 124. As shown, the reversal of the direction of movement of the optical card is effected within a time period of the pulse width t of the signal 127. The motor controller 125 starts the deceleration when the level of the signal 124 changes, stops the deceleration at the mid-point of the time period t, starts the acceleration in the opposite direction, and drives the motor at a steady speed at the mid-point of the time period t.
The signal 127 is applied to the analog switches 121-2 and 122-2, which control the status of the switches. When the pulse signal 127 is present (reversal), the terminal C of the switch 121-2 is closed and the terminal D is open. In the switch 122-2, the terminal A is closed and the terminal B is open. On the other hand, when the pulse signal 127 is not present (non-reversal), the terminal C of the switch 121-2 is open and the terminal D is closed. In the switch 122-2, the terminal A is open and the terminal B is closed. Accordingly, at the non-reversal time, the outputs from the amplifiers 121-1 and 122-1 are divided and they are supplied to the drivers 121-3 and 122-3, respectively. On the other hand, at the reversal time, the output voltages from the amplifiers 121-1 and 122-1 are not divided and supplied to the drivers 121-3 and 122-3, respectively. Thus, the AT gain and AF gain at the reversal time can be higher than those at the nonreversal time.
In FIG. 7, e shows the vibration in the AT direction only at the non-reversal time, and f shows the vibration in the AT direction including the reversal time. They are similar to a and b shown in FIG. 3, respectively. In the present embodiment, the AT gain is set to assume ε shown in FIG. 7 at the reversal time (that is, when the output from the amplifier 121-1 is applied to the driver 121-3 through the terminal C). At the non-reversal time, the output from the amplifier 121-1 is supplied to the driver 121-3 through the terminal D and the AT gain assumes δ shown in FIG. 7 which is a shift-down version of ε. The δ may be set to be equal to α shown in FIG. 3 by appropriately selecting a resistance between the terminals C and D and other constants.
Thus, at the non-reversal time, the degradation of the recorded and reproduced signals due to oversensitivity by the overgain is prevented. At the reversal time, sufficient AT and AF are attained even under a large high frequency vibration. At the reversal time, information is not recorded or reproduced and hence the signal is not degradated.
Similar gain setting may be done for the AF direction.
In the above embodiment, as shown in FIG. 7, the AT gain ε at the reversal time is raised relative to the AT gain δ at the non-reversal time. This is not absolutely necessary but it is sufficient to cover the vibration around the resonance frequency fp.
In accordance with the present invention, the direction of relative reciprocal movement between the light beam spot and the information track of the optical information recording medium is switched and the tracking servo gain and/or focusing servo gain are also switched so that a minimum required gain is set for each circumstance. Thus, at the non-reversal time, the degradation of the recorded and reproduced signals by the affect of defect or dust on the surface of the recording medium is prevented, and at the reversal time, the off-AT and off-AF are prevented. Accordingly, the reliability and error rate are improved.
FIG. 8 shows a configuration of another embodiment of the optical card recording and reproducing apparatus which is the optical information recording and reproducing apparatus of the present invention. The like elements to those shown in FIG. 5 are designated by the like numerals and the explanation thereof is omitted.
In FIG. 8, numeral 123 denotes a system controller which controls the recording and reproducing apparatus, and numeral 134 denotes a record mode/reproduce mode select control signal produced by the controller. The controller 123 also produces signals other than 134 although they are not shown. Numeral 135 denotes a motor driver which receives the signal 134 to set the rotation speed of the motor 106 to the recording or reproducing speed.
The signal 134 is applied to the analog switches 121-1 and 122-2 to control the status of the switches. When the reproduce mode signal 134 is applied, the terminal C of the switch 121-2 is closed and the terminal D is open. In the switch 122-2, the terminal A is closed and the terminal B is open. On the other hand, when the record mode signal 134 is applied, the terminal C of the switch 121-2 is open and the terminal D is closed. In the switch 122-2, the terminal A is open and the terminal B is closed. Accordingly, in the record mode, the output voltages from the amplifiers 121-1 and 122-1 are divided and they are supplied to the drivers 121-3 and 122-3. On the other hand, in the reproduce mode, the output voltages from the amplifiers 121-1 and 122-1 are not divided and supplied to the drivers 121-3 and 122-3, respectively. Thus, the AT gain and AF gain in the record mode may be set lower than those in the reproduce mode.
FIG. 9 shows a graph of frequency characteristics of the amplitude of vibration in the AT direction and the AT gain.
In FIG. 9, g represents a vibration in the AT direction in the record mode, and h represents a vibration in the AT direction in the reproduce mode. They are similar to c and d shown in FIG. 4. In the present embodiment, the AT gain in the record mode (that is, when the output of the amplifier 121-1 is applied to the driver 121-3 through the terminal D) is set to assume ζ of FIG. 9. The ζ is 60 dB at a frequency below the recording scan frequency 0.5 Hz and decreases at a rate of -12 dB/oct at a frequency above the scan frequency. In the reproduce mode, the output of the amplifier 121-1 is applied to the driver 121-3 through the terminal C. Thus, the AT gain assumes η of FIG. 9 which is a shift-up version of ζ. By appropriately selecting the resistance between the terminals C and D of FIG. 8 and other constants, the ζ is 60 dB at the reproducing scan frequency 2.5 Hz and decreases at a rate of -12 dB/oct at a frequency above the scan frequency.
Thus, in the record mode, the degradation of the recorded signal due to the oversensitivity by the overgain is prevented, and in the reproduce mode, sufficient AT and AF are attained.
Similar gain setting may be done for the AF direction.
In the above embodiment, as shown in FIG. 9, the AT gain ζ in the record mode is lower than the AT gain η in the reproduce mode. However, this is not absolutely necessary. For example, as shown in FIG. 10, the AT gain in the record mode may be ζ' which is lower than the AT gain in the reproduce mode only in the high frequency band.
In accordance with the present invention, the speed of the relative reciprocal movement between the light beam spot and the information track of the optical information recording medium is switched, and the tracking servo gain and/or focusing servo gain are switched so that a minimum required gain is set for each circumstance. Accordingly, at the low speed, the degradation of signal by the affect of defect and dust on the surface of the recording medium due to overgain is prevented, and at the high speed, the off-AT and off-AF are prevented. Thus, the reliability and error rate are improved.
In the above two embodiments, the gain is electrically changed. Alternatively, the gain may be changed optically, mechanically or electrically, or by combination thereof, because the AT gain and AF gain are determined by the products of the electrical gain, optical gain and mechanical gain. In order to change the optical gain, the intensity of the light source 107 may be changed, an ND filter may be inserted into a light path, or a variable transmissibility ND filter may be used to change the transmissibility of the filter. In order to change the mechanical gain, the number of turns of the tracking coil 111 may be changed or a distance between the tracking coil 111 and a magnet which is integral with the objective lens 110 may be changed.
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An optical information recording and reproducing apparatus for an optical information record medium on which a plurality of tracks are arranged substantially in parallel, comprises a light source, a first optical system for guiding a light beam from the light source, onto the record medium, a second optical system for obtaining the light beam from the record medium, a detecting device for receiving the light beam obtained by the second optical system to output at least one of a focusing signal and a tracking signal, an adjusting device for adjusting at least one of focusing and tracking operation in accordance with at least one of the focusing and tracking signals, a reciprocating device for causing the record medium to reciprocate, a control device for controlling the reciprocating device, and a change device for changing at least a servo gain of the adjusting device in accordance with at least a signal from the control device.
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BACKGROUND OF THE INVENTION
The present invention relates to improvements in a wave spring and particularly to improvements in a wave spring or imparting a linear weight versus deflection characteristic to a wave spring component.
A wave spring formed by winding a steel band having a flat cross section into a coil to serve as a spring structure is known. As shown in FIG. 10, a wave spring 1 has predetermined numbers of ridges 2 and troughs 3 per turn circumferentially disposed at a predetermined pitch such that the upper end of a ridge in one coil layer is opposed to the lower end of said trough in an adjacent coil layer thus forming a spring structure.
The coil shape of the said wave spring 1 is selected such that the magnitude of a deflection S produced when the wave spring 1 is subjected to an axial compression load P lies in a predetermined region of elastic deformation of the spring material, e.g. steel. For example, in the case where said wave spring is used in a clutch device of a speed changer for automobiles, it is desirable that a linear or substantially linear deformation characteristic be maintained between the load P imposed on the wave spring 1 by depressing the clutch pedal and the deflection S produced by said load, at least in its effective operation region.
FIG. 11 is a load versus deflection diagram for explaining by way of example said deformation characteristic. In the initial region I where the compression load P is started to be applied to the wave spring, the load versus deflection characteristic is unstable since the ridges 2 and the troughs 3 in the upper stage contact each other or since the clearance between the ridge 2 and the trough 3 of the wave spring varies in size. In contrast, in the terminal load region III, the ridges 2 and troughs 3 of the wave spring approach the closely contacted state, whereby the load P sharply increases with little change in deflection. Actually, the wave spring 1 functions as a spring structure in which the relation between the load P and the deflection S is maintained nearly linear only in the intermediate region II which is the effective operation region of the spring.
In this connection, heretofore used as a factor which determines the coil shape of the wave spring 1 is a deformation sine curve (TMS), shown in FIG. 13 (A) or a deformation trapezoid curve shown in FIG. 13 (B).
FIG. 12 is a perspective view showing a deflection measuring instrument 6 prepared fox measuring the elastic characteristics of the wave spring 1, with the wave spring 1 placed thereon. A wave spring, for example, the wave spring 1 whose coil shape is determined by the deformation sine curve (TMS), is seated on the deflection measuring instrument 6 and the deflection H produced by a distributed compression load P is measured. The deflection measuring instrument 6 is a spring structure support block comprising a pair of spring support flanges 4 disposed on opposite sides radially extending from a center point O, and a spring support surface 5 in the form of a sectorial planar plate which is connected to the inner lateral surfaces of the support flanges 4. In use, the wave spring 1 is positioned with its opposite ends abutting against the inner lateral surfaces of the support flanges 4 and a distributed compression load P is imposed on the center of the ridge 2 to measure the elastic deformation S produced in the wave spring 1.
The wave spring 1 experiences a decrease in the height H of the ridge 2 above the spring support surface 5 with the imposition of the distributed compression load P, and simultaneously therewith, the ends of the troughs 3 are slid along the inner lateral surfaces of the spring support flanges 4, resulting in a radially outwardly directed (indicated by the reference character R) diameter increasing movement. By measuring the amount of sink, i.e., elastic deformation H, of the ridge 2 while progressively increasing the distributed compression load P, a load versus deflection curve as shown in FIG. 11 is obtained.
As will be understood from the above description, if the coil shape of the wave spring 1 is designed to be a modified sine curve or modified trapezoid, the load versus deflection curve will be appreciably nonlinear even in the intermediate region II which is designed to be the effective operating region, as shown in FIG. 11. In the case where deflection v. load linearity is not retained in such linear load versus deflection characteristic, the width of selection of spring characteristics is narrowed, presenting such problems as an increase in the number of design steps and an increase in the characteristic testing period. As a result, deflection v. load linearity is no longer retained between load and deflection as in the clutch of an automobile speed changer having the wave spring 1 incorporated therein and, furthermore, the number of design steps is increased by repetition of trial making of wave springs; thus, the manufacturing cost of wave springs increases greatly.
SUMMARY OF THE INVENTION
As a means for solving the above problems, the present invention provides a wave spring formed by coiling a spring material of flat cross section, said wave spring being characterized in that said spring material which circumferentially extends has a shape represented by a clothoid curve and in that linearity is retained in the relation between a load imposed on said wave spring and a deflection produced thereby, and also provides a wave spring characterized in that the curved portion of said wave spring coiled in clothoid form is formed with a parallel portion in flat developed form, said parallel portion being tangentially connected to the terminal end of said clothoid curve.
In forming a spring structure by coiling a spring material of flat cross section, said circumferentially extending spring material is given a shape represented by a clothoid curve. Since such clothoid curve has a characteristic in which the radius of curvature continuously varies in inverse proportion to the length of the curve, linearity can be retained in the relation between load P and deflection S easily as compared with the modified sine curve or modified trapezoidal curve in which no continuity is seen in changes in radius of curvature.
As a result, buckling ascribable to the nonlinearity of changes in radius of curvature is substantially avoided.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a theoretical explanatory view of a clothoid curve;
FIG. 2 is a front view of a wave spring having formed therein a minimum unit of ridge and trough in a clothoid curve;
FIG. 3 is a view for explaining the order of making of the wave spring;
FIG. 4 is a view for explaining the order of making of the wave spring;
FIG. 5 is a view for explaining the order of making of the wave spring;
FIG. 6 is a view fox explaining the order of making of the wave spring;
FIG. 7 is a perspective view for explaining the shape characteristic of the wave spring;
FIG. 8 is a load versus deflection curve of a wave spring;
FIG. 9 is a load versus deflection curve of a wave spring;
FIG. 10 is a perspective view of a prior art wave spring having a wave portion formed on a deformed trapezoid curve basis however the wave spring of the instant invention resembles this spring in appearance only; the difference being in that the shape of the ridge and root sections have the shape of a clothoid curve, not visually distinguishable in the drawing.
FIG. 11 is a load versus deflection curve in the initial, intermediate and terminal regions of a prior art spring;
FIG. 12 is a loading view of a prior art wave spring placed on a deflection measuring instrument;
FIG. 13 (A) is a partial view of a prior art wave spring formed from a modified sine curve; and
FIG. 13 (B) is a partial view of a prior art wave spring formed from a modified trapezoidal curve.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
A concrete example of the present invention will now be describe using a comparative example with reference to FIGS. 1 through 9.
As will be understood from the theory of simple beams, the radius of curvature p upon imposition of a bending moment M of a flat wave spring is represented as a function of modulus of longitudinal elasticity E and second moment of area I, as indicated by the formula (1). ##EQU1##
That is, when the bending moment M is imposed on the wave spring, provided that the modulus of longitudinal elasticity E and second moment of area I are constant, the bending moment M changes in proportion of the inverse of the radius of curvature, 1/ρ, of the wave spring.
A wave spring 10 (so called if there is only one coil layer) can be treated as a simple beam from dynamic point of view. Therefore, when a distributed compression load P corresponding to said bending moment M is imposed on the pressure receiving surface, in order to establish an inversely proportional relation between the magnitude of the distributed compression load P and the inverse of radius of curvature, 1/ρ, it is necessary to select a coil shape curve such that the radius of curvature ρ continuously changes as the distributed compression load P increases.
In consideration of the above fact, as means for establishing a proportional relation between the distributed compression load P and the inverse of radius of curvature, 1/ρ, a clothoid curve has been selected.
That is, a clothoid curve CLO, as shown in FIGS. 1 and 2, is a curve whose radius of curvature ρ continuously changes in inverse proportion to the length of the curve CLO and mathematically it can be defined using the curve length u as a parameter, as indicated by the formula (2). ##EQU2## where u is the length of the curve and a is a proportionality constant. The tangent direction φ and the radius of curvature ρ at any point on the clothoid curve are respectively defined by the formulas (3) and (4). ##EQU3##
The functions x and y are difficult to treat as elementary functions, but the direction φ of a tangent can be calculated as functions of the length U.
Referring to FIGS. 3 through 6, the formation of the wave spring 10 using a clothoid curve will now be described by way of its concrete examples.
First, as shown in FIG. 3, the distance from the coil center O to the widthwise center of the wave spring 10, i.e., the length of half the ridge measured at the coil radius R (l=AB) and the height (h=AA') of the ridge are measured and an arc CD is cut out of a clothoid curve CLO. In cutting the arc CD, the cutting conditions are set such that in FIGS. 3 and 4, the condition that c/d=h/l is satisfied. In this connection, the segments CE and ED in FIG. 4 are determined such that the conditions that CD=c and ED=α are satisfied. In addition, φ indicates the angle of a tangent to the clothoid curve CLO at a point D.
As shown in FIG. 5, the are CD cut out in FIG. 3 is turned through 180 degrees around a point C for point-symmetrical development so as to form an are CD'. From the length of the arc CD', which is 2α, as measured on the axis DF (center axis) and the height of the are DD', which is 2C, as measured on the axis D'F which is orthogonal to said axis φ, a constant a is found such that the conditions that h=ac and l'=ad are satisfied, thereby forming the intended clothoid curve CLO.
Finally, coordinate transformation is made such that the tangent angle φ to in FIG. 5 is 0°. Then, the length of half the ridge (l'=AB) and the ridge height (h=AA') shown in FIG. 6 are determined. As a result, a clothoid curve CLO is formed such that the point B in FIG. 6 coincides with the point D in FIG. 5 and the point A in FIG. 6 coincides with the point D' in FIG. 5.
The resulting clothoid curve is used as the minimum unit of coil and a plurality of such clothoid curves are connected together to provide a wave spring 10 such that the waveform seen in the direction orthogonal to the coil axis O--O' is formed from a continuous body of clothoid curves.
The concrete example described above refers to the formation of the wave spring 10, which is formed only of the ridge 2 and troughs 3. However, as a modification, in the case where it is necessary to provide parallel portions 7 at the opposed ends of the troughs 3 as shown in FIG. 7 and table 1, such parallel portion 7 is connected to the terminal end of the clothoid curve portion 3 (the point B in FIG. 3) such that the parallel portion 7 forms a tangent φ to said terminal end.
TABLE 1______________________________________(A)______________________________________Thickness of steel band (T) 1.2 mmWidth of steel band (W) 5.5 mmCoil radius of steel band (R) 39.75 mmHeight of wave (H) 1.5 mmNumber of ridges per turn of coil 5.5 ridges per turnAngle per ridge (θ) 32.73 × 2°______________________________________(B) without parallel with parallel portion (-NF) portion (-F)______________________________________Clothoid curve (CLO) 45.53 mm 50.10 mmModified sine curve (TMS) 44.28 mm 48.61 mmSize of Circumferential 0 4.54 mmParallel lengthportion Angle 0° 6.55°______________________________________
(A) is a table showing the dimensions of a trial wave spring formed from a clothoid curve.
(B) is a table showing the dimensions of two trial wave springs formed of a clothoid curve and a modified sine curve.
To facilitate the understanding of the present invention, wave spring samples having the dimensions shown in FIG. 7 and Table 1 (A) and (B) and formed from a clothoid curve CLO were prepared and a distributed compression load P was imposed thereon to measure the relation between load P and deflection (S) in the same manner as in FIG. 12. As for the wave spring samples 10, there were prepared two types, one (CLO-F) having a ridge 2 and parallel portions 7 connected to the opposed ends of troughs 3 and the other (CLO-NF) having no parallel portions. Prepared as comparative examples were a wave spring sample (TMS-NF) formed solely of a modified sine curve and a wave spring sample (TMS-F) having parallel portions 7 connected to the opposite ends of a modified sine curve portion, as shown in Table 1, and the relation between load P and deflection S was measured in the same manner as described above. The respective results are shown in FIG. 8. FIG. 9 is a conceptional load versus deflection curve for clarifying the physical meaning for FIG. 8.
The formation of the wave spring 10 from a clothoid curve ensures that the radius of curvature ρ changes in inverse proportion to the length of the curve CLO. A spring structure having significant linearity is obtained. In the wave spring 10 according to the present invention, since the radius of curvature of the curve CLO continuously changes with the magnitude of the load to be imposed, the linearity of the curve CLO is improved to a great degree as compared with wave springs formed from the modified sine curve and modified trapezoidal curve shown in FIG. 13. As a result, in designing the wave spring 10, there is almost no possibility of occurrence of a difference between design and actually measured values, and significant effects are also obtained in respect of decreases in the number of manufacturing steps and in the number of wave springs produced on a trial manufacture basis.
Further, if it is necessary to add flat parallel portions 7 to the opposed ends of the troughs 3, continuity is retained between the parallel portions 7 and the curve portion CLO by connecting the parallel portions 7 to he terminal ends of the clothoid curves such that they are tangential thereto; Thus, bucking due to concentrated loading hardly occurs. Further, since a spring characteristic is obtained which can be practically regarded as a linear one approximate to that of the linear type wave spring 10 formed solely from a clothoid CLO, the size and specification of the wave spring 10 can be changed according to its uses despite the present of the parallel portions 7.
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A wave spring (10) is formed in which linear relation is retained between a load (P) and a deflection (S). Thereby, the degree of freedom of design of springs is enhanced.
In forming a spring structure by coiling a spring material having flat cross section, a clothoid curve is selectively used as a shape-determining factor for the spring structure.
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This application is a continuation of application Ser. No. 542,322, filed on Oct. 17, 1983, now abandoned.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to collapsible sealed containers to dispense liquid products, and more particularly to a flexible conduit incorporated in such a collapsible container.
2. Description of the Prior Art
Many exemplary collapsible containers are available in the prior art which permit the extraction of the product from a container. Most of the containers use conventional dip tubes including an elongated cylindrical tube which includes an upper portion connected to a valve and a lower portion positioned within the product to be extracted from the container. For example, Daniels, U.S. Pat. No. 3,171,571 discloses a conventional bag-in-box type of dispensing package including a dip tube.
Another example of a dip tube position within a flexible bag is disclosed by Kramer, et al. U.S. Pat. No. 2,859,899. The dip tube includes perforations through which the syrup or other material positioned within the flexible bag is sucked therefrom by means of a pump. U.S. Pat. No. 4,286,636 to Credle discloses a collapsible bag with an extruded dip tube including at least one channel in the peripheral surface of the dip tube and extending along substantially the entire length of the dip tube. As a vacuum or suction is applied to the dip tube by a pump, initially all of the air within the collapsible bag is extracted therefrom. Subsequently, the liquid product is dispensed out of the collapsible bag and the bag collapses around a portion of the dip tube which is no longer surrounded by the liquid product.
One of the disadvantages of the prior art collapsible containers including dip tubes is that they require the insertion of a dip tube, and thus of an additional step in the manufacture of the filled container. Additionally, because of the geometry of the dip tube and the collapsible container, the insertion of the dip tube could not be handled through automated means, but rather requires manual insertion.
SUMMARY OF THE INVENTION
Accordingly, it is a primary objection of the present invention to provide an internal flexible conduit for a collapsible container comprising a pair of rib members extending along substantially the entire length of the collapsible container.
It is another object of the present invention to provide a conduit which can be integrally formed on the interior surface of the collapsible container.
A further object of the present invention is to provide a flexible conduit for a collapsible bag which can be inserted during the formation of the bag and requires no manipulative steps after filling of the collapsible container.
The objects of the present invention are fulfilled by providing at least one pair of flexible substantially parallel rib members disposed adjacent to an interior wall of the collapsible container. The flexible members are positioned within a collapsible bag a substantially adjacent to an annular spout member. Initially, air within the collapsible bag will be drawn therefrom. Subsequently, the liquid product disposed within the collapsible bag will flow through a channel formed by the adjacent ribs and the collapsible bag will collapse around the rib members. Progressively, as the liquid product is removed from the collapsible bag, the bag will continue to collapse around the rib members until all of the liquid product is dispensed therefrom.
A further aspect of the present invention is that the rib members can be disposed on a web which can be disposed between two flexible sheets which comprise a collapsible bag during the manufacture of the the bag. The major advantage of this development is that it avoids substantial manipulative steps both in the manufacture and assembling of the collapsible container and in the filling and use of the bag.
Further scope of applicability of the present invention will become apparent from the detailed description given hereafter. However, it should be understood, that the detailed description of the invention and the specific examples, while indicating preferred embodiments of the invention are given by way of illustration only, since various changes and modifications within the spirit of the invention will become apparent to those skilled in the art from this detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will become more fully understood from the detailed description given herein below and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein:
FIG. 1 is isometric, partially cut away front side view of a collapsible bag according to the present invention;
FIG. 2 is an enlarged cross sectional partial view of the collapsible bag including an annular spout adjacent to which are disposed a plurality of ribs according to the present invention;
FIG. 3 is an exploded view of an embodiment of the present invention; and
FIG. 4 is a lateral cross sectional view of a collapsible bag which illustrates the operation of the invention.
DETAILED DESCRIPTION OF THE INVENTION
The present invention is directed to a collapsible container 10 which is used to dispense a liquid product therefrom. The collapsible container may be used in combination with a post-mix beverage system. Such a post-mix beverage system, which is hereby incorporated by reference, is disclosed in U.S. Pat. No. 4,014,461, issued Mar. 29, 1977 to Harvill and assigned to the same assignee as the present invention.
As illustrated in FIGS. 1 and 2, the collapsible container 10 is made of a pair of sheets of flexible material 12 and 14 joined together at their respective peripheries 16 and 18. The flexible sheets are joined in a sealed relationship throughout the periphery and in the case of flexible sheets made of thermoplastic material, this may be a seal achieved by means of heat sealing or suitable adhesive. The collapsible bag 10 includes an annular spout, or bag fitment 20 disposed through the flexible sheet 12 and attached thereto by means of an annular flange 22. The annular spout 20 may be of any desired geometry which can be adapted to fit into a coupling for a suction system. Indeed as would be obvious to a person of ordinary skill in the art, the annular spout 20 may be any shape including non-annular. As shown in more detail in FIG. 2, the flexible sheets 12 and 14 may comprise a number of plys, e.g. 24 and 26. In the preferred embodiment, two plys are used. Ply 24 is a web of 2 mil. EVA disposed adjacent to second ply 26 which is a bonded web made up of the following three sheets: 2 mil. EVA, 1/2 mil. metalized PET, and a 2 mil. EVA.
The collapsible container 10 of the present invention includes at least one pair of ribs 30 disposed throuch the length of the collapsible container 10, shown in FIG. 1, and in relation to the annular spout 20 so that the pair of ribs 30 passes substantially adjacent to, and in line with the opening 21 of the annular spout 20. Although a pair of ribs is described, a single rib or protrusion 30 of sufficient height would be sufficient to achieve the objectives of the invention, although not as efficiently as a pain of ribs. The ribs 30 are slight protrusions which are closely spaced together. The ribs 30 may be extruded onto the flexible sheet 14, or in the case of a two ply sheet, on the inner layer 24.
In the preferred embodiment, the ribs 30 are disposed on the flexible sheet opposite to the flexible sheet where the annular spout 20 is attached. However, the present invention will also encompass the placement of the ribs on the flexible sheet on which the annular spout 20 is disposed, which although not as efficient, also can provide significant advantages over the system shown in the prior art.
As illustrated in FIG. 3 another embodiment of the present invention includes a web strip 34 including at least one pair of ribs 30 disposed between the flexible sheets 12 and 14 and adjacent to, and in line with the annular spout 20. The web strip 34 should be made of compatible material with the flexible sheets 12 and 14. For example, if the interior ply of the sheets 12 and 14 is made out of EVA then the web strip 34 should be made of EVA or compatible material (e.g. low density polyethylene). The web strip 34 is attached to the flexible sheets 12 and 14 during the formation of the bag, when the adjacent sheets are secured at their periphery, thus, for example heat sealing of the adjacent flexible sheets 12 and 14 will also achieve the heat sealing and fixation of the flexible strip web 34. Illustrated in FIG. 4 is the operation of the ribs 30. As the flexible container 10 collapses, it has a tendency to collapse somewhat unevenly, leaving pockets of liquid which may become isolated from the rest of the liquid in the container. The ribs 30 form a conduit which cannot be closed off by the atmospheric pressure on the walls of the flexible sheets 12 and 14. Thus, the entire inner chamber of the flexible bag remains in communication with the spout 20 at all times during the operation.
The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would obvious to one of ordinary skill in the art are intended to be included within the scope of the following claims.
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A collapsible container comprising a flexible bag including a spout having an opening through which liquid is fed into and dispensed from the bag, and a liquid passage member inside of the bag in liquid communication with the spout opening for aiding in the dispensing of liquid from the bag. The liquid passage member is preferably integral with a wall of the bag.
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FIELD OF THE INVENTION
The present invention relates to food serving devices and more specifically to devices with immobilized dishes to minimize spillage.
BACKGROUND OF THE INVENTION
The spilling of both food and beverages by infants and toddlers has long been a problem and concern of those raising the youngsters. Not only is the article of food wasted by the time and effort needed to clean-up after the infant could be spent in more productive pursuits. Additionally, the aggravation and frustration the individual caring for the infant experiences is unnecessary and a stress in life that should be alleviated.
It is conventionally known to provide a void in a surface into which a cup, glass or the like can be inserted to provide support. While this approach provides adequate support during carrying of articles stored therein, since they aren't fixedly attached to the support the cup or glass may have a tendency to cant to one side or another thus spilling its contents.
In the past, various patented inventions have tried to eliminate the spillage problem and resultant aggravation but none has proved to present a viable solution. Pat. No. 1.925,540 issued to Neuschotz discloses a bracket for the support of kitchen glassware and the like. The invention provides for the storage of the articles under the surface of the counter or table in order to improve space utilization. While the invention has the merit of providing a means of storage for the glassware or the like, it would be ill-suited to be used as a method of securing the glassware or the like when consuming food and beverages therefrom.
SUMMARY OF THE INVENTION
By the present invention, an improved apparatus for the fixed attachment of food receptacles to a platform is provided which readily lends itself to ease of use and functionality. The securing of dishes to a high chair tray provides for the prevention of spillage due to the carelessness of children.
Accordingly, one of the objects of the present invention is to provide an improved means of retention of dishes and the like for use by children for the prevention of unwanted spillage.
Additionally, an object of the present invention is to provide a functional solution to the problem of children's spillage which results in wasted food and also time which is necessary to clean up after the child.
A further object of the present invention is to provide a high chair tray which is readily convertible from a platform that provides for the retention of dishes and the like to one which provides a flat surface much like the conventionally known high chair tray.
With these and other objects in view which will more readily appear as the nature of the invention is better understood, the invention consists in the novel combination and arrangement of parts hereinafter more fully described, illustrated and claimed with reference being made to the attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a top plan view of the platform showing an exploded and in place representation of the food receptacles and retainers;
FIG. 2 is a cross-sectional view taken at II showing the detail of the notch;
FIG. 3A is a perspective view of the dish-like food receptacle;
FIG. 3B is a perspective view of the glass including the cover and straw;
FIG. 4 is a perspective view of the plug to secure the food receptacles;
FIG. 5 is a perspective view of the plug to fill the notches when the dishes are not in use;
FIG 6 is a perspective view of the platform of the second embodiment including a food receptacle adapted for use with the retention means of the second embodiment; and
FIG. 7 is a detail of the retention means and food receptacles of the second embodiment.
Similar reference characters designate corresponding parts throughout the several figures of the drawings.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1, the serving unit generally designated 1 is shown to include a platform 2, a plurality of food servers or receptacles 3 and a plurality of plugs 4 and 6.
The platform 2 is seen to have a periphery similar to a conventionally known high chair tray including a top face 22, a bottom face 20 and an arcuate edge 21 which is generally perpendicular to the top and bottom faces. The platform 2 also includes a plurality of notches 5 about said periphery.
The notches 5 are substantially U-shaped and serve to receive the food receptacles 3 and plugs 4 and 6. The notches 5 include side walls 51 and a semi-circular inner wall 5a which lie substantially perpendicular to the top 22 and bottom 20 faces. The notches 5 include a channel 50 along the entire perimeter. The channel is to receive the tracks 40 and 60 located on the plugs 4 and 6, respectively. The channel is an indentation in the wall 51 and provides for mating with both the track 40 of the filler plug member 4 and the track 60 of plug 6. Also, the bases 30 of the food receptacles 3 mate with the channel 50.
The filler plug 4 is provided with a periphery that mates with the notch 5. The plug includes an upper surface 41, a lower surface 42 and a plurality of walls. These walls include an exterior wall 43, a semi-circular inside wall 44 and side walls 45. The side walls 45 are generally planar and along the centerline thereof, parallel to the surfaces 20, 22, lies the male track 40. The inside wall 44 is provided with a channel 46 mating with the periphery of the food receptacle bases as will be seen hereinafter. The periphery of each track is to mate with the channel 50 of the notch 5. The track 40 is truncated before the edge of the wall. The exterior wall 43 has a periphery which has a radius of curvature that is identical to the radius of curvature of the missing portion of the platform edge 21.
The food receptacles shown in FIGS. 3A and 3B include both a bowl type body 32 and a cup-like body 31 with a cover 33. The bodies include a base 30 which mates within the channel 50 of the notch 5 and channel 46 of the filler plug 4. In addition to the mating of the base 30 to the channel 50, the base arcuate periphery mates with the arcuate slot 45 of the plug 4. This mating facilitates the tight-fit of the insertable bodies and retention of the same. The cover 33 includes an aperture 34 through which the flexible straw 35 is inserted. The straw 35 is provided with flexibility by the accordion style indentations 36.
The plug member 6 is provided for use in the notches 5 when it is desired that the surfaces 20 and 22 and edge 21 be continuous and thus the notch "filled". Included on the plug member 6 is a track 60 to mate with the channel 50 of the notch 5. The use of the plug member 6 provides for the continuity of the platform surfaces and convertibility to a conventionally known high chair tray.
The second embodiment shown in FIG. 6 shows an alternate means of securing the bodies 31' and 32'. The platform 2' includes on its top surface 22' a pair of oppositely facing clips 7. These clips mate with the diametrically opposed tabs 34' to provide retention of the bodies 32' and 31' therebetween.
Each clip 7 is a substantially "C" shaped member which lies substantially perpendicular to the top surface 22'. The clip includes a base 71, a neck 72 and a top lip 73 and is made of a resilient material. The base 71 provides for the attachment point to the top surface 22'. It is essentially flat and flush with the top surface 81. The neck 72 rises from the base 71 and forms the "C" shape. At the end of the neck 72, lies the lip 73. The lip 73 serves to brace and hold the tab 34' through the spring action of the resilient neck. The front edge 35' of the tab 34' slides into the opening provided by the clip 7 and the rear edge 36' makes contact with the lip 73 thus retaining the body.
The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications, and equivalents which may be resorted to, will be understood to fall within the scope of the invention.
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A tray for use on a high chair in which provision is made for immobilizing food receptacles such as bowls and cups through the use of static retainers which are part of the structure of the tray. One form of the invention utilizes grooved indentations to hold a mating base of a food receptacle. A second embodiment uses surface clips to hold the base of a food container.
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BACKGROUND OF THE INVENTION
This invention relates to sealing rings for adjacent flange surfaces, especially seal rings utilizing plastic deformation.
Mechanically separable joints in ultra high vacuum systems are most reliably sealed by plastic deformation of metal elements or gaskets. Typical seals are:
(1) Crushed wire rings, of gold, copper, or aluminum
(2) Step seal with flat gasket
(3) Coined gasket seal
(4) Knife edge seal
(5) "Conflat" seal (Varian Associates)
(6) "Cryofit" tube fitting (Raychem Corporation)
(7) "Helicoflex" seal (Carbone-Lorraine Industries Corporation)
In all these seals the sealing force is applied normal to the seal line, because no relative motion of the seal elements can be tolerated other than plastic deformation.
Some very large vacuum systems potentially of great importance cannot be sealed with any of these closure systems because the components to be sealed together cannot approach each other along paths perpendicular to the mating surfaces. An example of such seals are those between torus sections of a 16-segment vacuum vessel of a segmented Tokamak Fusion reactor. Each wedge-shaped segment spans 221/2° and the closure surfaces approach each other along a sloping path of 111/4°, i.e., 783/4° away from the normal. During gasket compression therefore the sliding between seal surfaces would be roughly five times as great as the gasket compression. What is needed is a gasket which can be installed without being loaded, then expanded and plastically deformed after the sealing surfaces are positioned and clamped together. An inflatable O-ring seal would have the necessary installation characteristics, but the service conditions sometimes (as in the Tokamak) preclude the use of elastomers.
SUMMARY OF THE INVENTION
An all-metal bakeable ultra high vacuum seal with plastic deformation of the seal which during installation has the contour of a deflated inflatable O-ring seal, but after installation assumes the sealing characteristics of a "helicoflex" seal.
The seal assembly is installed between flange surfaces in contact with only one of the surfaces until the entire closure is assembled and restrained. Sealing is then accomplished by plastic deformation of a seal assembly wrapper against the flanges. The energy to expand and deform the wrapper is provided by restoration of the shape of a shape-memory alloy component inside the wrapper as it undergoes a martensite-austenite transformation with rising temperature.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an isometric schematic of wire shaped into a helical coil;
FIG. 2 is an isometric schematic showing the installation of the wire within a wrapper;
FIG. 3 is an isometric schematic illustrating the mechanical deformation of the seal after chilling;
FIG. 4 is an isometric schematic of an installed, chilled seal; and
FIG. 5 is an isometric schematic of an installed seal after thermal deformation (warming).
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
In the following, the details of the invention are described via the steps for manufacture.
Refer to FIG. 1, in which a wire 1 of a shape-memory alloy in its austenitic phase is wound into a closed helical coil 11. Coil 11 is then formed into the shape of the gasket and the ends 2, 3 are joined together. In this condition it is annealed to stabilize its shape.
As shown by FIG. 2, a wrapper 4 is then put over coil 11 with its open side 10 away from the vacuum space, and its ends are joined by welding to make a continuous ring. Wrapper 4 is the material which will be elastically deformed to close the seal, and is chosen to be a substance capable of little or no additional workhardening, so that elastic deformation will proceed uniformly.
The assembly is chilled to transform the shape-memory alloy to martensite. It is then reduced in thickness in a press with chilled die-plates, and is maintained in the chilled condition. The dotted lines 5 in FIG. 3 illustrate the unchilled configuration while the solid lines shown the chilled and deformed assembly.
The chilled seal, as in FIG. 4, is placed in a groove 7 in one chilled flange 6, the mating flange 8 is slid into place along its slightly inclined approach path, and flanges 6, 8 are clamped or bolted together to resist the anticipated sealing force. The seal assembly still is in contact with only one flange 6.
The flanges 6, 8 and seal assembly are allowed to warm up through the transition temperature range of the shape-memory alloy. Coil 11 becomes again austenitic, but is prevented from again assuming its "remembered" circular cross-section, being restrained by flanges 6, 8. The restraining force acts through wrapper 4 and plastically deforms it to seal it against flanges 6, 8. This is shown in FIG. 5. Because of similarity in construction to the "Helicoflex" seal, it is anticipated that this seal can be made to cover the same size range, i.e.:
External Diameter--4 mm to 8000 mm
Section Diameter--1.6 mm to 25 mm
Min. Radius of Curvature--Three times the Section Diameter
Max. Seal Line Length--25.13 meters (82.5 feet)
There are real lower and upper limits to the operating temperature of this seal. The service temperature should preferably be above the transition temperature of the shape-memory alloy, so that the seal can be deformed, stored, and installed with the shape-memory alloy in the martensitic phase; according to the manufacturer of the Ni-Ti alloy "Nitinol", this temperature can be predetermined by minor (proprietary) alloying additions to be wherever desired between a low cryogenic temperature to well above the boiling temperature of water. If the service temperature is below the transition temperature, the seal can be installed and deformed by heating; upon cooling to the service temperature, the shape-memory component will transform without deformation to the lower strength martensitic phase, i.e., the gasket pressure will be reduced. The upper service temperature limit for very long exposure times is about 650° F., above which creep begins to cause relaxation of the force resulting from the "unresolved" strain; this temperature is consistent with Nitinol being basically a titanium alloy.
The shape-memory alloy may be "Nitinol", a reasonably well characterized Ni-Ti alloy produced commercially by Raychem Corportion and Allegheny International Corporation. Equivalent results could probably be obtained using the "Proteus" copper-base shape-memory alloys available from N. V. Baekert S. A. and Metallurgie Hoboken-Overpelt in Belgium.
This seal can be used between two coaxial surfaces, not necessarily round, by radial expansion similar to that of a static O-ring. This type of seal requires that the wrapper be in the radial gap between the annular surfaces.
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An all-metal expandable high vacuum seal which expands to a shape suitable for sealing during a material crystallization phase change of one component from martensitic to austenitic.
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FIELD OF THE INVENTION
This invention relates generally to injection molds for molding objects out of thermoplastics, aluminum, and the like, and more particularly to a method and device for controlling the temperature of such a mold during molding processes.
BACKGROUND OF THE INVENTION
Injection molding is a well-known process used for the fabrication of plastic or metal objects or parts having complex shapes. In the injection molding process, a molten material, such as a plastic or a metal, is introduced into a mold and allowed to set or cure by cooling. Once the molten material is set or cured, the mold is opened, and the molded object is released. The temperature of the mold is preferably controlled throughout the molding process, for example to ensure the quality of the molded object, and to maximize production throughput.
Proper temperature control is important when the molten material is injected into the mold, for example to avoid problems such as incomplete fill, poor part weld, and excessive stress in the part. The optimal mold temperature specified by the material manufacturer is typically well above room temperature, so proper temperature control usually requires heating the mold before introducing molten material into the mold.
Various methods can be used to heat injection molds to an optimal temperature before introducing molten material. For example, the mold can be heated simply by introducing molten material. This approach may necessitate a startup cycle wherein the first few molded parts contain defects, for example because of incomplete fill, and these defective parts must be discarded or recycled until the mold reaches an adequate temperature to produce parts that are free of defects. Another disadvantage of using molten material to heat the mold is that the mold must keep molding parts without interruption, or the mold will cool and the startup cycle and its associated waste must be repeated. Depending on the work environment, this startup cycle could be needed every morning, lunchtime, or coffee break. Similarly, variations in the delay between molding of successive objects can result in variations in the temperature of the mold when the successive objects are molded, which may reduce the uniformity of the successive objects.
External heat sources can also be used to heat the mold to an optimal temperature, for example electric heating elements or heated fluid can be used. These external heat sources can be applied to the mold in a variety of ways known in the art. External heat sources can avoid the required startup cycle and waste associated with using molten material to heat the mold. This approach can also ensure that the mold temperature remains consistent across the molding of successive objects, thereby improving the uniformity of the successive objects.
To produce high quality molded parts, optimum temperature control may require the application of heat in a non-uniform fashion, both across the area of the mold and over time. Heat can be applied at the periphery of the mold to heat the entire mold to a temperature which is essentially uniform across the molding surface, or applied in a non-uniform fashion to specific portions of the molding surface, for example the extremities of the mold cavity that may be the areas most likely to experience problems such as incomplete fill. Heat can be applied continuously over time, as a pulse of heat at a certain point in the mold cycle, or in a time-varying fashion.
Proper temperature control is also important after the molten material has been injected into the mold, during the period of time when the molded object sets or cures. When hot molten material is injected into a mold, the mold absorbs heat from the molten material and the temperature of the mold will increase toward the temperature of the molten material being injected into the mold. Thus, after molten material has been injected into the mold, it is desirable to provide cooling to remove heat from the mold and the molten material contained in the mold so that the molded object will set or cure, for example, to improve the quality of the objects being molded or to increase the productivity of the mold.
As with heating, optimum temperature control may require the application of cooling in a non-uniform fashion, both across the area of the mold and over time. Cooling can be applied at the periphery of the mold to cool the entire mold uniformly, or applied in a non-uniform fashion to specific portions of the mold, for example, the hottest areas of the mold such as thick portions of the mold cavity that receive a relatively large volume of molten material, portions near the injection channel for molten material that receive molten material that is relatively hot, or portions adjacent to heating elements. Cooling can be applied continuously over time, as a pulse at a certain point in the mold cycle, or in a time-varying fashion.
Proper temperature control after the molten material has been injected into the mold can affect the quality of the molded parts in a number of ways. For example, it is generally desirable to control the eventual temperature and cooling rate so that the plastic or metal object being molded exhibits the least possible amount of shrinkage and distortion during the setting or curing process. It is also important to control the application of cooling so as to ensure uniformity among replications of the object being molded.
In addition to improving the quality of the molded objects, proper temperature control can maximize productivity of the mold. For example, to minimize the setting or curing time after molten material has been injected the mold should be quickly cooled to an optimal temperature for setting or curing the object being molded, at the maximum rate possible which will nonetheless result in a molded object of acceptable quality. Similarly, after a first object is molded and removed from the mold, the mold should be heated quickly to an optimal temperature for receiving a new injection of molten material to form a second object, at the maximum rate possible which will not damage the mold or otherwise adversely affect the molding process.
Temperature control of an injection mold has been accomplished by circulating fluid through channels fashioned in the walls of the mold. In such a system, fluid is heated and then circulated through the mold to heat the mold to an optimum temperature before the first injection or “shot” of hot plastic or metal material is introduced into the mold. Because there is good thermal conductivity between the mold and the fluid, the temperature of the mold will be close to the temperature of the fluid until molten material is injected into the mold. The optimum temperature of the fluid and the mold is usually well above room temperature but below the temperature of the hot molten material.
Upon the introduction of the hot molten material, the temperature of the mold increases above the temperature of the fluid. The temperature of the fluid, however, is maintained at the optimum temperature, for example using an external heat exchanger or chiller. The continuous circulation of the fluid removes heat from the mold, thereby returning the temperature of the mold (and the molten material forming the object being molded) to a temperature at or near the temperature of the fluid so that the object being molded sets or cures. With this approach, the fluid can be circulated through the mold substantially all the time that the mold is being used to make successive replications of the object being molded.
Methods and devices for controlling the temperature of a fluid-cooled injection mold without the need for a continuous flow of cooling fluid are described in U.S. Pat. Nos. 4,354,812 and 4,420,446 to Horst K. Wieder, et al. These patents describe methods by which an injection mold can be maintained at a desired operating temperature using a cooling fluid which need not be elevated to or maintained at an ideal operating temperature. Accurate control of the temperature of an injection mold can be achieved by mounting a temperature sensor onto or within the mold. The temperature sensor provides an output signal indicative of the mold temperature. If the sensed mold temperature exceeds a selected control temperature level, a valve is opened to allow cooling fluid to enter the cooling channels in the mold, to thereby cool the mold. When the temperature sensor indicates that the mold is cooled below the control temperature, the valve is closed. Since cooling fluid is not continuously pumped through the mold cooling channels, the cooling fluid need not be heated to a particular operating temperature and the consumption of cooling fluid is reduced.
Another method of injection mold temperature control is described in U.S. Pat. No. 5,427,720 to Kotzab. Typically, a plurality of cooling channels are formed in an injection mold to provide cooling fluid to the mold. This patent describes determining, empirically or by calculation, a selected distribution profile for distributing cooling fluid among the cooling channels to achieve the desired amount of cooling of the injection mold. Depending upon the shape of the object being molded, certain portions of the injection mold may require more cooling than others. At the same time during each molding cycle, a temperature sensor signal is used to determine the temperature deviation of the mold from a desired temperature. Simultaneously, valves are opened to provide pulses of cooling fluid through the cooling channels in the pre-determined distribution profile. The duration of the cooling pulses is determined by the measured temperature deviation.
For some applications, the “pulse” cooling injection mold temperature control schemes just described may employ ordinary tap water as the cooling fluid. However, for many molding operations, the operating temperature of an injection mold can be very high. For example, the operating temperature of an injection mold for a high temperature molding process may be 300 F or higher, and the molten material injected into the mold may typically be at 700 F or higher. Water may be unsuitable as a cooling fluid for such high temperature molding operations without additional measures, such as pressurization, since water at normal atmospheric pressure will instantly turn to steam upon entering the cooling fluid channels of such a high temperature injection mold.
Petroleum-based oils or synthetic heat transfer fluids have been employed as cooling fluids for controlling the mold temperature of high temperature injection molding operations. The use of such materials for high temperature injection mold cooling has several important limitations, however. Such fluids have an inherently poor heat transfer rate. Thus, the time needed during a production cycle to bring the injection mold to the desired operating temperature using such fluids is relatively long, thereby increasing the cycle duration, and decreasing the production rate.
Furthermore, petroleum based oils are difficult to work with and potentially dangerous. The combination of petroleum-based oil and high temperatures presents a fire hazard. The use of oil-based cooling fluids can also adversely affect the quality of a molded object. Hydrocarbon molecules from the cooling oil can get into the mold itself. These molecules will leave flow marks on the molded plastic or metal object. These flow marks can adversely affect the quality and appearance of the molded object. In particular, flow marks on an aluminum die cast object, caused by oil based cooling fluid contamination, will prevent finishing of the aluminum object in the affected area. If the die cast aluminum object cannot be finished properly, it must typically be scrapped or recycled.
SUMMARY OF THE INVENTION
The present invention passes pressurized air contained in an air supply tube through an orifice member into an exhaust channel, wherein the pressure of the air in the exhaust channel is lower than the pressure of the air in the air supply tube, thereby producing cooling at the orifice member. The orifice member is mounted in thermal communication with a portion of an injection mold where cooling is desired, whereby the cooling at the orifice member can be used to control the temperature of the portion of the injection mold where cooling is desired.
A variety of structures can be used in a method and apparatus according to the invention. The air supply tube and exhaust channel can be, for example, aluminum tubes or holes bored in an injection mold. The air supply tube and exhaust channel may have any shape, for example they are not necessarily cylindrical or elongated. The air supply tube and exhaust channel are not necessarily concentric, although they can be. The orifice member can be formed in a variety of ways, for example, as a tube having a small hole in its side or end, a disc or plug having a small hole, a partially opened valve, a porous or fibrous plug, a tortuous tube, or a capillary tube.
Thermal communication between the orifice member and a portion of an injection mold where cooling is desired can also be accomplished in a variety of ways. For example, the orifice member can be mounted in direct contact with the portion of the injection mold where cooling is desired. Alternatively, the orifice member can be mounted in thermal contact, using a heat sink, thermal grease, or other structure or material providing thermal conductivity, with the portion of the injection mold where cooling is desired. The orifice member can be mounted so that at least a portion of the pressurized air released through the orifice member strikes the portion of the injection mold where cooling is desired. The orifice member can also be mounted so that at least a portion of the pressurized air released through the orifice member strikes a heat sink or other structure having a high level of thermal conductivity, where that heat sink or other structure is in thermal contact with the portion of the injection mold where cooling is desired. Of course, a combination of these approaches can be used to provide thermal communication between the orifice member and the portion of the injection mold where cooling is desired.
In a preferred embodiment according to the invention, an air compressor produces pressurized air that is cooled using one or more after coolers. The cooled pressurized air is supplied to one end of an insulated air jet tube that is centrally mounted in an exhaust channel bored into an injection mold. The other end of the insulated air jet tube is sealed except for a small hole, and that end of the insulated air jet tube is positioned adjacent to an area of the mold in which cooling is desired. A portion of the cooled pressurized air in the insulated air jet tube passes out of the small hole into the exhaust channel, whereby cooling occurs in the vicinity of the small hole including the area of the mold in which cooling is desired.
According to another aspect of the invention, an air supply valve is mounted to regulate the flow of pressurized air to an air supply tube supplying pressurized air to an orifice member mounted in thermal communication with a portion of a mold to be cooled, in order to adjust the magnitude and timing of cooling of that portion of the mold (for example to assure that a molded object is properly set to achieve a high quality part, while minimizing the cooling time in order to maximize the production rate). The air supply valve is opened or closed to regulate the flow of pressurized air to the orifice member at one or more selected times and selected durations to adjust the magnitude and timing of cooling.
According to another aspect of the invention, an air exhaust valve is mounted to regulate the back pressure in an exhaust channel which receives air from an orifice member mounted in thermal communication with a portion of a mold to be cooled, in order to adjust the magnitude and timing of cooling. The exhaust valve is opened to vent the exhaust channel and reduce the back pressure in the exhaust channel, thereby increasing the amount of cooling provided at the orifice member. The exhaust valve is closed to block the exhaust channel and increase the back pressure in the exhaust channel, thereby decreasing the amount of cooling provided at the orifice member.
According to another aspect of the invention, a source of pressurized air, wherein the pressure of the supplied air is adjustable, supplies pressurized air to an air supply tube that supplies air to an orifice member, wherein the orifice member is mounted in thermal communication with a portion of a mold to be cooled and wherein the orifice member exhausts the air to an exhaust channel, in order to adjust the magnitude and timing of cooling. The pressure of the supplied air is increased or decreased to vary the difference in the air pressure between the air supply tube and the exhaust channel, thereby increasing or decreasing the amount of cooling provided at the orifice member.
According to another aspect of the invention, an orifice member having an adjustable size aperture is mounted in thermal communication with a portion of a mold to be cooled, and the size of the aperture of the orifice member is used to adjust the magnitude and timing of cooling. For example, the adjustable size aperture orifice member can be comprised of a partially opened valve whose degree of opening can be adjusted or controlled. Similarly, a porous plug can be selected from a plurality of porous plugs having pores of various sizes, or a fibrous plug can be selected from a plurality of fibrous plugs having fibers of various densities, or a capillary tube can be selected from a plurality of capillary tubes of various sizes, to form an orifice member whose aperture size can be adjusted or controlled.
According to another aspect of the invention, an orifice member having a plurality of orifices mounted in close proximity to one another is mounted in thermal communication with a portion of a mold to be cooled, wherein at least one orifice in the plurality of orifices can be opened and closed independently of at least one other orifice in the plurality of orifices, and the number of orifices open in the plurality of orifices is used to adjust the magnitude and timing of cooling.
According to another aspect of the invention, a variety of techniques can be used to control the timing or magnitude of cooling of a portion of a mold to be cooled by controlling any of the above control variables (opening or closing an air supply valve, opening or closing an air exhaust valve, adjusting the pressure of supplied air, adjusting the effective size of an aperture of an orifice member, or adjusting the number of open orifices in an orifice member having a plurality of orifices.
For example, one or more temperature values can be monitored using one or more temperature sensors which can be, for example, mounted to monitor the temperature of a portion of the mold to be cooled, a portion of the object being molded, a portion of the pressurized air or air supply tube, or a portion of the exhaust air or exhaust channel. A process controller can receive one or more of the monitored temperature values and adjust one or more of the aforementioned control variables, individually or in combination, to control the magnitude and timing of cooling provided by one or more orifice members.
One or more air flow values can be monitored using one or more flow sensors which can be, for example, mounted to monitor the flow of air in one or more air supply tubes, orifice members, or exhaust channels. A process controller can receive one or more of the monitored air flow values and adjust one or more of the aforementioned control variables, individually or in combination, to control the magnitude and timing of cooling provided by one or more orifice members.
One or more of the aforementioned control variables, individually or in combination, may also be adjusted at one or more selected times and selected durations during each molding cycle to provide pre-set amounts of cooling at specific points in the molding cycle.
More than one air supply valve, air exhaust valve, pressurized air supply, or orifice member can be employed to provide cooling through one or more orifice members or pluralities of orifice members placed in thermal communication with different portions of the mold. The openings and closings of such air supply valves or air exhaust valves, the pressures of the supplied air from such pressurized air supplies, the effective aperture sizes of such orifice members, the number of orifice members which are open in a plurality of orifice members, or the number of orifices which are open in an orifice member having a plurality of orifices can be controlled independently to provide optimized cooling in different parts of the mold to assure product quality and maximize production rates.
Injection mold cooling employing air in accordance with the present invention can be implemented in either a closed loop system, in which the air is recycled, or an open loop cooling system, in which the air is exhausted to the atmosphere.
In either a closed loop or an open loop system, the pressurized air can be cooled, filtered, dehumidified, humidified, or otherwise processed, or surfactants, cleaners, water, water vapor, or other substances can be added, for example to help keep impurities from building up in the cooling system or to improve the cooling efficiency of the cooling system. In either type of system, the pressurized air supply can be connected directly to an air supply channel leading to a cooling orifice member, or the pressurized air supply can be connected to an air supply valve that controls the flow of pressurized air to an air supply channel leading to a cooling orifice member. In either type of system, air passing out of the cooling orifice member travels through an exhaust channel, which may include an air exhaust valve.
In an open loop cooling system in accordance with the present invention, pressurized air for cooling an injection mold is obtained directly from the atmosphere, compressed using an air compressor to provide a pressurized air supply, and, after passing through the orifice member for cooling, exhausted to the atmosphere via a muffler.
In a closed loop cooling system in accordance with the present invention, the pressurized air used in the cooling process is retained in a closed system. A closed loop cooling system can be preferred when the pressurized air is filtered, dehumidified, or otherwise processed to make the pressurized air more suitable for pressurization or more suitable for use with an orifice member to provide cooling.
A closed loop cooling system may also be preferred when a gas or a mixture of gases other than pressurized air, for example carbon dioxide or nitrogen, is employed for injection mold cooling in accordance with the present invention. The use of processed air or a purified gas may prevent impurities from clogging the orifice members, air supply tubes, exhaust channels, or other air flow components over time. This can be especially important in regard to the orifice members, since the relatively small size of the apertures in the orifice members means that even minimal deposits of impurities in the aperture of an orifice member can change the effective size of that aperture and thereby change the magnitude of cooling provided by that orifice member.
Pressurized air or other gas from a single compressor or pressurized storage tank can be used to supply pressurized air or other gas simultaneously to multiple air supply valves associated with multiple cooling orifice members. These multiple cooling orifice members can be located at multiple locations in a single injection mold or at multiple locations in multiple injection molds in accordance with the present invention. Each such cooling orifice member can have an independent air supply valve associated therewith such that the air flow to that cooling orifice member can be controlled independently by a process controller, or a single air supply valve can be used to control air to multiple cooling orifice members through an air supply manifold. Similarly, each such cooling orifice member can have an independent exhaust air valve associated therewith such that the back pressure to that cooling orifice member can be controlled independently by a process controller, or a single exhaust air valve can be used to control back pressure to multiple cooling orifice members through an exhaust air manifold.
Injection mold cooling in accordance with the present invention provides many advantages over previous methods of controlling the temperature of injection molds, and can be employed in any type of injection molding application, e.g., for forming plastic or metal objects and for high or low temperature applications. Since pressurized air is used for mold temperature control, the potential fire hazard associated with using petroleum based oils for high temperature mold cooling is eliminated. Pressurized air will not contaminate or damage a molded object, as can oil-based cooling fluids. The location of an orifice member (and therefore the position of the cooling effect provided by that orifice member) and the size and number of orifice members (and therefore the magnitude of the cooling effect at multiple positions) can be changed more readily than the location and magnitude of cooling produced by cooling channels carrying oil or other cooling fluids. Thus, the present invention provides improved cooling of injection molds for the production of high quality molded objects at a high production rate.
Further objects, features, and advantages of the invention will be apparent from the following detailed description when taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
FIG. 1 is a cross-sectional view of an injection mold and exemplary mold cooling apparatuses in accordance with the invention, with the injection mold shown in the closed position.
FIG. 2 is a cross-sectional view of an exemplary apparatus for mold temperature control according to the invention.
FIG. 3 is a cross-sectional view of another example of an apparatus for mold temperature control according to the invention.
FIG. 4 is a cross-sectional view of an alternative example of an apparatus for mold temperature control according to the invention.
FIG. 5 is a cross-sectional view of a another exemplary apparatus for mold temperature control according to the invention.
FIG. 6 is a cross-sectional view of an exemplary orifice member for use in a method and apparatus according to the invention.
FIG. 7 is a cross-sectional view of another example of an orifice member for use in a method and apparatus according to the invention.
FIG. 8 is a cross-sectional view of an alternative example of an orifice member for use in a method and apparatus according to the invention.
FIG. 9 is a cross-sectional view of another exemplary orifice member for use in a method and apparatus according to the invention.
FIG. 10 is a block diagram of a cooling apparatus according to the invention.
DETAILED DESCRIPTION OF THE INVENTION
Referring to the drawings, FIG. 1 is a cross-sectional view of an exemplary injection mold which includes various aspects and embodiments of an apparatus for mold temperature control using air in accordance with the invention. The exemplary injection mold, shown generally at 10 , is in the closed position in FIG. 1 . The injection mold 10 includes a mold cavity 11 having one or more molding surfaces 12 . The mold cavity 11 receives molten material 13 for forming a molded object, for example using one or more injection channels 14 to inject the molten material 13 into the mold cavity 11 . The mold cavity 11 may have one or more central portions 15 , one or more extremity portions 16 , and one or more intermediate portions 17 . The injection mold may include one or more heater elements 18 , for example an electrical rod heater mounted in a machined groove or drilled hole or attached to the mold perimeter.
An apparatus for mold temperature control using air in accordance with the invention may include an air supply port 20 for receiving pressurized air 21 from an air supply system, indicated generally at 22 , and an air exhaust port 23 for discharging exhaust air 24 to an air exhaust system, indicated generally at 25 . In each of the embodiments shown in FIG. 1 , it should be understood that each air supply port 20 is connected to an air supply system 22 (which can be independent or shared by multiple air supply ports), although only one such connection is shown in FIG. 1 . Similarly, it should be understood that each air exhaust port 23 in FIG. 1 is connected to an air exhaust system 25 (which can be independent or shared by multiple air exhaust ports), although only one such connection is shown in FIG. 1 .
An exemplary air supply system 22 may include an air intake 30 , an air compressor 31 , an after cooler 32 , a water cooled after cooler 33 , and an air supply valve 34 , although this is not required and other structures for providing pressurized air 21 can be used. An exemplary air supply system 22 may cool the pressurized air 21 , for example the output of the air compressor 31 can be coupled to the input of the after cooler 32 , and the output of the after cooler 32 can be coupled to the input of a water cooled after cooler 33 . The output of the water cooled after cooler 33 can be coupled to the input of an air supply valve 34 , and the output of the air supply valve 34 can be coupled to one or more air supply ports 20 . In an open loop system, the air intake 30 may receive air directly from the atmosphere, while in a closed loop system the air intake 30 may receive air from an air exhaust system 25 .
An exemplary air exhaust system 25 may include a mixing muffler 35 , for example to combine the exhaust air 24 with cooler air or to reduce noise levels, although this is not required and other structures for exhausting air can be used. In an open loop system, the air exhaust system 25 may release the exhaust air 24 directly to the atmosphere. In a closed loop system, the air exhaust system 25 may return the exhaust air 24 to an air intake 30 of an air supply system 22 for recycling. One or more insulation plates 26 can be used to reduce heat transfer from the injection mold 10 to the air supply system 22 and the air exhaust system 25 .
As shown in FIG. 1 , an apparatus for mold temperature control using air in accordance with the invention may include one or more temperature sensors 40 , each having a temperature signal connector 41 . Each temperature sensor 41 can include a temperature sensing element 42 (such as a thermocouple, thermistor, resistive temperature detector, or infrared detector) that is preferably at least partially disposed within a protective housing 43 , for example a flexible metal sheath. One or more temperature sensors 40 can be positioned in proximity to a molding surface to form one or more molding surface temperature sensors 44 for measuring the temperature of the molding surface. One or more temperature sensors 40 can be positioned at other suitable locations on, in, or near the mold, to form one or more periphery temperature sensors 45 for measuring the temperature of various portions of the mold. Although this is not shown in FIG. 1 , it should be understood that the temperature signal connector 41 of each temperature sensor 40 can be connected to a process controller 46 as shown in FIG. 6 , whereby the process controller 46 may receive temperature signals or data from the one or more temperature sensors 40 for use in controlling the temperature of one or more portions of the mold.
In a first embodiment of an apparatus for mold temperature control using air in accordance with the invention as shown generally in FIG. 1 and in greater detail in FIG. 2 , a first air jet cooling assembly, indicated generally at 50 , provides cooling adjacent to a central portion 15 and an extremity portion 16 of the mold cavity 11 . An air supply port 20 can be coupled, for example, to one or more air supply bores 51 to form an air supply manifold 52 . The air supply manifold 52 can be coupled to one or more air supply tubes 53 , preferably using one or more air supply tube fittings 54 . Each air supply tube 53 is preferably at least partially surrounded by an insulating jacket 55 . Each air supply tube 53 supplies air to at least one orifice member 60 that can be formed, for example, by sealing the distal end 56 of the air supply tube 53 except for a small aperture.
The orifice member 60 is adapted to be in thermal communication with a portion of the mold where cooling is desired, for example by positioning the orifice member 60 adjacent to or in contact with that portion of the mold or by positioning the orifice member 60 so exhaust air 24 from the orifice member 60 flows onto that portion of the mold. Additional structures, for example, one or more heat sinks, cooling fins, or heat conduction elements, can also be used to enhance the thermal communication between the orifice member 60 and the portion of the mold where cooling is desired.
The orifice member 60 is adapted to receive pressurized air 21 from an air supply tube 53 , and to release a portion of the pressurized air 21 into an exhaust channel 61 as exhaust air 24 . This can be accomplished, for example, by positioning the orifice member 60 at the distal end 56 of an air supply tube 53 located in an exhaust channel 61 . It is believed that the cooling which occurs at the orifice member may be due to the Joule-Thomson effect, but it is understood that the invention is not limited by a particular theory of the underlying physics. The exhaust channel 61 may include, for example, a plurality of exhaust bores 62 to form an exhaust manifold 63 . The exhaust manifold 63 can be connected to an air exhaust port 23 coupled to an air exhaust system 25 .
In a second embodiment of an apparatus for mold temperature control using air in accordance with the invention as shown generally in FIG. 1 and in greater detail in FIG. 3 , a second air jet cooling assembly, indicated generally at 70 , provides cooling adjacent to a central portion 15 of the mold cavity 11 . An air supply tube 53 having a distal end 56 and a proximal end 57 is centrally mounted in a combination bore 71 . An end plug 72 can be used to seal the proximal end 73 of the combination bore 71 .
An air supply port 20 supplies pressurized air 21 to the air supply tube 53 , for example via a side air supply bore 74 coupled to a side feed air supply fitting 75 mounted to the proximal end 57 of the air supply tube 53 . The air supply tube 53 supplies pressurized air 21 to at least one orifice member 60 . The air supply tube 53 is preferably at least partially surrounded by an insulating jacket 55 .
The orifice member 60 is adapted to receive the pressurized air 21 from the air supply tube 53 , and to release a portion of the pressurized air 21 into an exhaust channel 61 as exhaust air 24 . The exhaust channel 61 releases the exhaust air 24 to an air exhaust system 25 , for example by releasing the exhaust air 24 into a portion of the combination bore 71 that is coupled to a side air exhaust bore 76 leading to an air exhaust port 23 , where the air exhaust port 23 is coupled to an air exhaust system 25 .
The orifice member 60 is adapted to be in thermal communication with a portion of the mold where cooling is desired, for example by positioning the orifice member 60 adjacent to or in contact with that portion of the mold. A compression spring 77 can be positioned between the end plug 72 and the side feed air supply fitting 75 to apply compression force against the side feed air supply fitting 75 to press the distal end 56 of the air supply tube 53 into contact with the distal end 78 of the combination bore 71 .
In a third embodiment of an apparatus for mold temperature control using air in accordance with the invention as shown generally in FIG. 1 and in greater detail in FIG. 4 , a third air jet cooling assembly, indicated generally at 80 , provides cooling adjacent to an intermediate portion 17 of the mold cavity 11 . An air supply tube 53 having a distal end 56 and a proximal end 57 is centrally mounted in a combination bore 71 . An end plug 72 can be used to seal the proximal end 73 of the combination bore 71 .
An air supply port 20 supplies pressurized air 21 through the air supply tube 53 , for example via a side air supply bore 74 leading to a horizontal air supply bore 81 coupled to a horizontal feed air supply fitting 82 mounted to the proximal end 57 of the air supply tube 53 . The air supply tube 53 supplies pressurized air 21 to at least one orifice member 60 . The air supply tube 53 is preferably at least partially surrounded by an insulating jacket 55 .
The orifice member 60 is adapted to receive the pressurized air 21 from the air supply tube 53 , and to release a portion of the pressurized air 21 into an exhaust channel 61 as exhaust air 24 . The exhaust channel 61 releases the exhaust air 24 to an air exhaust system 25 , for example by releasing the exhaust air 24 into a portion of the combination bore 71 coupled to a horizontal air exhaust bore 83 leading to a side air exhaust bore 76 that leads in turn to an air exhaust port 23 .
The orifice member 60 is adapted to be in thermal communication with a portion of the mold where cooling is desired, for example by positioning the orifice member 60 adjacent to or in contact with that portion of the mold. A compression spring 77 can be positioned between the end plug 72 and the horizontal feed air supply fitting 82 to apply compression force against the horizontal feed air supply fitting 82 to press the distal end 56 of the air supply tube 53 into contact with the distal end 78 of the combination bore 71 .
In a fourth embodiment of an apparatus for mold temperature control using air in accordance with the invention as shown generally in FIG. 1 and in greater detail in FIG. 5 , a third air jet cooling assembly, indicated generally at 85 , provides cooling to a portion of the injection mold 10 , for example, a portion located between a heater element 18 and a central portion 15 of the mold cavity 11 .
An air supply port 20 supplies pressurized air 21 to an air supply tube 53 . The air supply tube 53 can be formed, for example, as a first portion 86 of an inline bore 87 . The air supply tube 53 supplies pressurized air 21 to at least one inline orifice member 88 that can be formed, for example, as a disk or plug having a small aperture and mounted at an intermediate position in the inline bore 87 .
The inline orifice member 88 is adapted to receive the pressurized air 21 from the air supply tube 53 , and to release a portion of the pressurized air 21 into an exhaust channel 61 as exhaust air 24 . The exhaust channel 61 can be formed, for example, as a second portion 89 of an inline bore 87 leading to a side air exhaust bore 76 that leads in turn to an air exhaust port 23 . The inline orifice member 88 is adapted to be in thermal communication with a portion of the mold where cooling is desired, for example by positioning the inline orifice member 88 adjacent to or in contact with that portion of the mold.
FIG. 6 shows a first exemplary orifice member 90 for use in a method and apparatus according to the invention. The orifice member 90 includes a disk 92 having a central aperture 91 and mounted within an air supply tube 53 . One or more notches 93 can be formed in the air supply tube to allow exhaust air to escape from the periphery of the exhaust tube. The air supply tube 53 can be centrally mounted within an air exhaust channel 61 , for example within an air exhaust bore 62 and preferably in contact with the distal end 64 of the air exhaust bore 62 . An insulating jacket 55 preferably surrounds at least a portion of the air supply tube 53 .
FIG. 7 shows a second exemplary orifice member 94 for use in a method and apparatus according to the invention. The second exemplary orifice member 94 may include one or more peripheral apertures 95 that can be formed, for example, as holes in an air supply tube 53 . The air supply tube 53 can be mounted within an air exhaust channel 61 , for example within an air exhaust bore 62 and preferably in contact with the distal end 64 of the air exhaust bore 62 . An insulating jacket 55 preferably surrounds at least a portion of the air supply tube 53 .
FIG. 8 shows a third exemplary orifice member 96 for use in a method and apparatus according to the invention. The third exemplary orifice member 96 can be formed as a restriction, for example a disk having a small hole, a porous plug, or a capillary tube, between a first portion 86 and a second portion 89 of an inline bore 87 .
FIG. 9 shows a fourth exemplary orifice member 97 for use in a method and apparatus according to the invention. The orifice member 97 includes one or more peripheral notches 98 formed on the periphery of the distal end 56 of an air supply tube 53 . The air supply tube 53 can be centrally mounted within an air exhaust channel 61 , for example an air exhaust bore 62 . By positioning the distal end 56 of the air supply tube 53 in contact with a solid structure, for example the distal end 64 of an air exhaust bore 62 , the distal end 56 of the air supply tube 53 is sealed, except for the peripheral notches 98 that thereby form apertures from the orifice member 97 . An insulating jacket 55 preferably surrounds at least a portion of the air supply tube 53 . A standoff 99 can be used to keep the air supply tube 53 centered within the air exhaust channel 61 .
FIG. 10 shows a block diagram of the various components of a cooling apparatus according to the invention. The apparatus may include a process controller 46 , for example a conventional programmable controller or general purpose computer. The apparatus may include one or more user interface devices, for example one or more status indicators 101 or visible alarms 102 , for example a light emitting diode (LED), liquid crystal display (LCD), incandescent light, colored panel, or the like. The apparatus may include a general purpose information display 103 , for example a flat panel display or cathode ray tube (CRT) display. The apparatus may include one or more input devices 104 , for example a keyboard, switch, touch screen, mouse, key lock, pen input, or the like. The apparatus may include one or more audio devices 105 , for example an audible alarm, speaker, or the like for providing audible status, information, help, or alarm messages. The apparatus may include a communications interface 106 , for example an twisted pair ethernet interface, 802.11 wireless network interface, RS-232 serial interface, or the like, to provide status and control communication with external control or monitoring systems.
The controller 46 can be adapted to receive status information for use in controlling the timing and magnitude of heating or cooling that is applied to portions of the injection mold. For example, the controller 46 may receive air flow information from one or more air flow sensors 107 positioned to measure air flow, for example in an air supply tube 53 , in an orifice member 60 or inline orifice member 95 , or in an air exhaust channel 61 . The controller may receive temperature information from one or more temperature sensors 40 .
The controller 46 can be adapted to control the timing and magnitude of heating that is applied to portions of the injection mold by activating a heater 18 .
The controller 46 can be adapted to adjust or control various components of the apparatus for controlling the timing and magnitude of cooling that is applied to portions of the injection mold. For example, the controller 46 may open, partially open, close, or partially close one or more air supply valves 108 or air exhaust valves 109 . The controller 100 may open, partially open, close, or partially close an adjustable size aperture 110 in an orifice member. The controller 46 may open, partially open, close, or partially close a switchable orifice member 111 . The controller may adjust or control the pressure of the pressurized air produced by an adjustable pressure air supply 112 .
There are various possibilities with regard to alternative embodiments and applications of a method and apparatus using air for controlling the temperature of an injection mold.
Although the exemplary embodiments of the present invention refer to air as the gas for operation, other gases known to those skilled in the art as having suitable properties can be appropriately substituted. For example, nitrogen or carbon dioxide gases could be used in an appropriate case.
Although the exemplary embodiments of the present invention show air supply tubes and air exhaust channels comprised of one or more elongated cylinders, other shapes can be used. It is not important to the invention that either the air supply tubes or the air exhaust channels are either elongated or cylindrical.
It is understood that the invention is not limited to the particular embodiments described herein, but embraces all such modified forms thereof as come within the scope of the following claims.
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A method and apparatus for controlling the temperature of an injection mold passes pressurized air contained in an air supply tube through an orifice into an exhaust channel, wherein the pressure of the air in the exhaust channel is lower than the pressure of the air in the air supply tube. As the pressurized air is released through the orifice, cooling is produced that can be applied to a portion of an injection mold where cooling is desired, in order to control the temperature of that portion of the injection mold.
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BACKGROUND OF THE INVENTION
The present invention relates to press rolls.
In particular, the present invention relates to press rolls for treating sheet material such as paper and suitable for use in the calender or press section of a paper machine.
The present invention relates in particular to a press roll having a shaft surrounded by a shell which is spaced from and rotatable with respect to the shaft, the shell and shaft defining between themselves a gap in which is located a structure capable of receiving a pressurized fluid for controlling the deflection of the shell.
Press rolls of the above general type are known. The known rolls include an inner shaft and an outer shell surrounding and rotatable with respect to the shaft, and while there is a pressure zone extending between the shaft and shell, it is not possible with the previously known constructions to vary the pressure acting on the shell, particularly longitudinally of the roll. In this connection reference may be made to the German Federal Republic Pat. No. 1,026,609.
Also known in the art is a press roll for achieving a uniform pressure and having between the shaft and shell a component in the form of a cushion-like hollow member filled with a pressurized fluid and retained in place by shoulders at the edges of a recess formed in the shaft. The outer surface of the cushion-like hollow member engages a slip membrane against which the inner surface of the shell slides. A construction of this type is disclosed in German Federal Republic Pat. No. 1,111,932.
Also, there is a known press roll having its shaft provided with radially directed pressure cylinders in which pistons operate, with suitable slide shoes engaging the inner surface of the shell for receiving the forces provided by the pistons. A structure of this type is disclosed in German Federal Republic Pat. No. 1,193,792.
Also, a previously known press roll has formed in its shaft a longitudinal pressure groove in which a bar slides to operate as a piston, with a slide piece being provided and having a length equal to that of the shell, this latter piece being rigid and non-rotatably fixed to the shaft and transmitting the force to the inner surface of the shell. This pressure groove may be divided into compartments by means of partitions, with the bar which serves as a piston being correspondingly subdivided into sections so that different pressures may be achieved in the compartments, respectively. A construction of this type is disclosed in U.S. Pat. No. 3,119,324.
The known constructions of the above type suffer from several drawbacks. For example the shafts of such constructions are not as strong as desired because of the fact that such shafts require hollow interior portions to accommodate pressure-controlling structure. Also, it is not possible with the previously known constructions to achieve the desired pressure controls with the precision which is desired and in such a way that the shell can have different pressures distributed longitudinally thereof.
Moreover, the sealing structure utilized in the conventional press rolls is exceedingly complex, often requiring separate seals on the one hand to extend longitudinally of a pressure zone and on the other hand to be situated at the ends of the pressure zone.
SUMMARY OF THE INVENTION
It is accordingly a primary object of the present invention to provide a construction which will avoid the above drawbacks.
In particular, it is an object of the present invention to provide a pressure roll of the above general type which has an exceedingly strong shaft having a high degree of rigidity.
Furthermore it is an object of the present invention to provide a construction of the above type according to which the deflection of the shell can be controlled or adjusted so as to be capable of providing uniform pressures of various magnitudes as well as capable of achieving a non-uniform pressure distribution capable of correcting the sheet material in a desired manner, if necessary.
It is also an object of the present invention to provide for a press roll of the above type a sealing structure wherein the same type of seals can be used along the longitudinal sides as well as at the ends of the pressure zone.
Furthermore it is an object of the present invention to provide a construction according to which the shape of the pressure zone can be freely selected.
According to the invention the press roll includes a stationary shaft and a shell coaxially surrounding and spaced from the shaft; a bearing means being provided to support the shell for free rotary movement about the common axis of the shaft and shell. In a gap which is defined between the shaft and shell there is a sealing means which defines and surrounds a given pressure zone for sealing the latter, and fluid under pressure is supplied to this pressure zone by way of a duct means which extends through the shaft and communicates with the pressure zone.
BRIEF DESCRIPTION OF DRAWINGS
The invention is illustrated by way of example in the accompanying drawings which form part of this application and in which:
FIG. 1 is a fragmentary longitudinal sectional schematic illustration of a preferred embodiment of the invention;
FIG. 2 is a fragmentary longitudinal section of part of a roll as illustrated in FIG. 1, the section of FIG. 2 being taken along line 2--2 of FIG. 3 in the direction of the arrows;
FIG. 3 is a transverse section of the structure of FIG. 2 taken along line 3--3 of FIG. 2 in the direction of the arrows;
FIG. 4 is a fragmentary longitudinal section of another embodiment of a press roll according to the invention, the section of FIG. 4 being taken along line 4--4 of FIG. 5 in the direction of the arrows;
FIG. 5 is a transverse section of the structure of FIG. 4 taken along line 5--5 of FIG. 4 in the direction of the arrows;
FIG. 6 is a longitudinal sectional elevation of a third embodiment of a press roll according to the invention; and
FIG. 7 is a fragmentary sectional elevation of yet another embodiment of a roll according to the invention.
DESCRIPTION OF PREFERRED EMBODIMENTS
Referring first to the embodiment of the invention which is illustrated in FIGS. 1-3, the press roll illustrated therein includes a rigid stationary shaft 1 carrying at its opposed reduced ends bearings 2 and 3 which serve to support for rotary movement with respect to the shaft 1 an outer shell 4 supported by the bearing means 2,3 for free rotary movement with respct to the stationary shaft 1. The shell 4 has an outer surface 6 which forms the outer surface of the press roll of the invention. The inner surface of the shell 4 is spaced from the outer surface 18 of the shaft 1 so as to define with the latter the cylindrical gap 5. In this gap 5 there are a plurality of pressure zones situated closely adjacent to each other and distributed longitudinally along the gap, parallel to the common axis of the shaft 1 and the shell 4, and some of these pressure zones 9, 11, and 12 are illustrated in FIG. 1, these pressure zones being of course arranged in a row at the region where the press roll engages the sheet material. Each of these pressure zones in the illustrated example is surrounded and defined by a sealing means. In the embodiment of FIGS. 1-3 the sealing means for each zone includes a slide shoe component 16 which is relatively rigid and of the arcuate configuration apparent from FIG. 3, the sealing means including in addition to the slide shoe a resilient packing means which in the embodiment of FIGS. 1-3 takes the form of a substantially square resilient packing 8 for each pressure zone. The slide shoe 16 of the sealing means of each pressure zone is formed with an endless groove 22 at its surface which is directed toward the shaft 1, and the resilient packing 8 is adhered in the groove 22 of the slide shoe as by being cemented thereto. At its periphery the slide shoe 16 has an endless flange having the flange portions 23, 24, 25, 26, illustrated in FIGS. 2 and 3, and the outer edge of the packing 8 engages this endless flange so that the latter acts to retain the packing means 8 in its proper position.
It will be noted particularly from FIGS. 2 and 3 that the resilient packing means 8 of each pressure zone has an inner edge region directed inwardly toward the pressure zone and having the form of a pair of separate lips defining between themselves a space into which the fluid under pressure extends for pressing these lips respectively against the slide shoe 16, in the groove 22 thereof, and the outer surface of the shaft 1. Thus FIGS. 2 and 3 show the lip 29 pressed by the fluid under pressure against the exterior surface of the shaft 1. In this way an exceedingly effective seal is provided for the pressure fluid.
Each of the pressure zones is placed in communication with a source of fluid under pressure by way of a duct means which communicates with the pressure zone and extends through the shaft 1. Thus it will be seen that the pressure zone 9 communicates through the duct 10 with the exterior of the shaft 1, at the left end thereof, as viewed in FIG. 1. The duct means for each pressure zone takes the form simply of a pair of bore portions one of which extends parallel to the axis of the shaft 1 and the other of which extends radially from the axial bore portion to the particular pressure zone. Thus FIG. 1 illustrates not only the duct means 10 for the pressure zone 9 but also the duct means 13 for the pressure zone 11 and the duct means 14 for the pressure zone 12, and of course additional pressure zones and ducts means are provided as is apparent from FIG. 1. Thus each pressure zone has its own duct means in the form of a suitable passage or bore formed in the shaft 1. These several duct means communicate at the left end of the shaft 1 with suitable pipes or tubes which in turn communicate with a pressure pump and with separate pressure controls respectively provided for the several tubes or pipes which respectively communicate with the several duct means, so that in this way it is possible to provide separate pressure regulation for the separate zones. The manner in which separate pressure regulation can be provided for each of the pressure zones is known and therefore not illustrated since it forms no part of the present invention. Thus, by way of the independent pressure regulation of the zones which are arranged one closely next to the other in a row it is possible very precisely to regulate the deflection of the roll along its entire length.
A connecting means is provided for connecting the slide shoe 16 of each pressure zone to the shaft 1 so as to prevent each slide shoe 16 from turning with the shell. For this purpose the slide shoe 16 has along one longitudinal edge, namely the edge where the flange portion 23 is located, an extension 20 of this flange portion, this extension 20 projecting into a groove 21 formed axially along the exterior of the shaft 1, so that in the manner shown in FIG. 3, the slide shoe 16 is prevented from turning together with the shell 4. Each slide shoe 16 is formed with a central opening through which the lubricating oil, which also acts as the pressure fluid, has access to the inner surface 31 of the shell 4. In this way a hydrostatic lubrication is provided.
As is apparent from FIGS. 2 and 3, at its outer edge region which is formed with the groove 22 the shoe 16 has a thickness which is almost equal to the thickness of the gap 5. Thus in the event that the force provided by the fluid under pressure is too small to oppose the force acting on the shell, the shell will in any event be supported by the shoe 16 which acts as a back-up member to limit the extent to which the shell can be deflected toward the shaft. A suitable return pipe is provided for the oil which leaks, and since such a leakage oil return pipe is known it is not illustrated.
In the embodiment of the invention which is illustrated in FIGS. 4 and 5, the press roll also has a substantially rigid stationary shaft 41. The shell 44 surrounds the shaft 41 and is supported by suitable unillustrated bearings so as to define with the shaft 41 the gap 45. Thus, the shell 44 provides the roll with its exterior acting surface portion 46. In this embodiment also the gap 45 is longitudinally subdivided into a series of pressure zones 49 situated in a row closely adjacent to each other and each defined by an endless sealing means at each zone. In this case the sealing means includes a slide shoe 56 which is in the form of a portion of an elongated slide shoe member which is common to all of the pressure zones 49 and which has a uniform thickness. Between the slide shoe 56 and the shaft 41 the sealing means includes the resilient packing means 48 which has the configuration of a ladder, in that the resilient packing means 48 has a pair of longitudinal side portions extending in common along the entire series of pressure zones 49 and between these longitudinal side portions the arcuate transverse portions, two of which are shown in FIG. 4, with each of these transverse portions of the packing 48 being common to and separating a pair of adjacent pressure zones 49. In this embodiment the shaft 41 is formed with grooves 63 having a configuration conforming to that of the packing means 48 and receiving the latter so as to retain the packing means 48 in position. The resilient packing means 48 is in the form of a flexible tubular structure, made of a suitable elastic material, and the interior of this structure communicates through a suitable unillustrated tube with a source of fluid under pressure which thus becomes situated in the interior space 47 of the packing 48. This pressure is provided by way of a suitable pump and the pressure provided in the space 47 of the packing 48 exceeds the pressure in each pressure zone 49. In this embodiment the duct means for each pressure zone 49 takes the form of a flexible tube 50 communicating with each pressure zone 49 in the manner shown for the tube 50 illustrated in FIGS. 4 and 5. Thus the shaft 41 is provided with radial bores respectively receiving radial portions of the several tubes 50. Also the shaft 41 is formed with a common axial bore 72 into which all of the tubes 50 extend, this axial bore 72 extending all the way to one of the ends of the shaft 41 so that the several tubes 50 can respectively communicate with the source of fluid under pressure which can be separately regulated for the several tubes 50 so that the series of pressure zones 49 can be respectively provided separately with predetermined pressures. Thus, with this embodiment also it is possible very precisely to control the deflection of the roll along the entire length thereof. As is apparent from FIG. 5, the slide shoe 56 has along one of its longitudinal edges a flange 60 extending into the axial groove 61 formed in the shaft 41, so that this structure forms a connecting means for connecting the slide shoe 56 to the shaft 41 in the manner preventing the slide shoe 56 from turning with the shell 44. At each of the pressure zones 49 the slide shoe 56 is formed with a relatively large opening 64 which has an area which is only slightly smaller than the area of the pressure zone. The common slide shoe member of which each shoe 56 forms a portion is of a uniform thickness throughout its entire length.
The press roll of the invention may have between the slide shoe and shaft, instead of resilient packings as described above, other types of packings, and instead of utilizing flanges, for example, to maintain the packing in position, the resilient packing may be fixedly attached both to the slide shoe and the shaft in any well known manner such as by being adhered to these components with a suitable cement. Each pressure zone with the above embodiments may have its pressure controlled in a stepless manner independently of the other pressure zones by way of a suitable pressure regulator so that along the entire length of the roll the supporting force provided by the fluid under pressure for the roll at the several pressure zones can have any desired magnitude and can be distributed in any desired way longitudinally along the pressure roll. The control of the supporting force may be brought about by selecting suitable valves the particular pressure for a particular pressure zone from among a number of regulated pressures which are available. It is also possible to exercise for each pressure zone either a predetermined pressure or for the possibility of eliminating any pressure from a particular pressure zone, so that certain zones may be in a pressure-free state. For this purpose the duct means which communicates with the particular pressure zone can simply be placed in communication with the outer atmosphere.
Thus, in accordance with the invention the distribution of the supporting force present in the roll may be controlled in such a way that the pressure zones are provided with pressure regulated for the entire roll, and some of the pressure zones if desired may be provided not only with pressures different from pressures in other zones but also some of these zones may be rendered pressure-free by the use of suitable valves provided for this purpose. Thus it is possible to maintain an overall-regulated pressure or a differential pressure longitudinally along the roll. The resilient packing which forms part of the sealing means may if desired also have lips directed outwardly away from the pressure zone.
Of course instead of the above-described connecting means for connecting the slide shoe to the shaft, other means which are known may be used, such as, for example, pins and mating the bores which respectively receive the pins.
As is apparent from the above description, the press roll of the invention has a rigid shaft of large diameter, and this shaft is entirely solid with the exception of the extremely small bores or grooves which are provided to form the duct means leading the pressure fluid to the several pressure zones in the case of FIGS. 1-3 or provided for receiving the flexible tubes 50 of FIGS. 3 and 4.
In the gap between the shell and shaft, this gap being of a small radial dimension, there is an extensive possibility of controlling pressure along the several pressure zones which are separated from each other by the sealing means. Thus it is possible to obtain for the roll of the invention either a uniform pressure or a non-uniform pressure distribution. It will be noted that the shaft of the roll of the invention has no bores for accommodating pressure cylinders or to form pressure cylinders or the equivalent thereof, so that such a construction need not detract from the strength of the shaft.
As contrasted with prior art press rolls, the roll of the invention has a shaft of greater rigidity so that it is capable of withstanding higher pressures while at the same time there is the possibility of controlling the deflection of the shell in the most varied manner.
Referring now to the embodiment of the invention which is illustrated in FIG. 6, this embodiment includes a stationary shaft 81 which has a great rigidity. The shaft 81 is surrounded by the rotary shell 84 which has the surface 86 which acts on the sheet material. The shell 84 is supported for rotary movement by a bearing means as illustrated in FIG. 6 and as was described above in connection with FIG. 1. Between the shell 84 and the shaft 81 there is the cylindrical gap 85 where the elongated pressure zone 89 of FIG. 6 is located. This pressure zone extends along substantially the entire length of the shell. The sealing means of this embodiment includes the slide shoe 96 which has the arcuate ends shown in FIG. 6 and the longitudinal portions extending therebetween parallel to the axis of the shaft 81, this slide shoe 96 engaging the inner surface 92 of the shell 84, thus surrounding the pressure zone 89. This slide shoe 96 is prevented from rotating with the shell as by a connecting means of the type described above. The sealing means includes in addition to the slide shoe 96 a resilient packing 88 in the form of elongated tubular member of elastic material extending along the slide shoe 96 between the latter and the shaft 81. The shaft 81 is formed with a groove which receives the endless resilient packing means 88 to maintain the latter in its proper position. This seal 88 also endlessly surrounds the pressure zone 89.
FIG. 6 illustrates the duct means 90 which has a construction which is the same as the duct means 10 of FIGS. 1-3, for example, this duct means serving to direct the fluid under pressure into the pressure zone 89. Thus the fluid under pressure will in this case directly engage the exterior surface 98 of the shaft 81 as well as the interior surface 92 of the shell 84. Thus with the embodiment of FIG. 6 there is a large pressure zone. A suitable lubricating oil can be used as the pressure fluid so as to also serve for lubrication purposes. Thus the pressure in the pressure zone 89 presses the slide shoe 96 against the hydrodynamically lubricated inner surface 92 of the shell 84, thereby providing a supporting force at the area where the slide shoe 96 is located. In the area of the large opening 94 of the shoe 96 the pressure medium produces a hydrostatic supporting force directed immediately at the inner surface 92 of the shell 84.
A further possible embodiment of the invention is illustrated in FIG. 7. FIG. 7 schematically illustrates a shaft 100 which may have the same construction as any of the above shafts as well as an outer shell 102 which may have the same construction as any of the above shells and which is supported in the same way for free rotation with respect to the stationary shaft 100. In this embodiment there is situated between the shell 102 and the shaft 100, in the gap 104 a resilient bag 106 made of rubber, for example, and having a configuration which corresponds to that of the desired pressure zone. This bag 106 communicates through a tubular extension 108 with a source of fluid under pressure such as a suitable liquid, and the shaft 100 is formed with bores for the tubes 108. A suitable slide shoe 110 is provided between the bag 106 and the inner surface of the shell 102, and in this case lubricant from a separate source is provided to lubricate the interface between the shoe 100 and the shell 102. Thus, in this embodiment it is the outer peripheral edge region of the bag 106 which forms the sealing means for the pressure zone which in this case is determined by the bag 106 itself, with the pressure fluid which acts on the shell being effective through the wall of the bag 106 and the slide shoe 110. Thus in this embodiment the entire pressure fluid for a given pressure zone is confined within the bag 106 whose outer edge region forms the sealing means.
Of course, a tube similar to the tube 108 may communicate with the sealing means 48 of FIGS. 4 and 5 to supply fluid under pressure to the hollow interior 47 thereof.
The slide shoe 110 of FIG. 7 is maintained stationary with respect to the shell 102 in any suitable way as by the above-described constructions, and the bag 106 may be maintained stationary either by adhering it to the exterior surface of the shaft 100 and/or the interior surface of the slide shoe 110, and/or by providing the slide shoe 110 with an exterior peripheral flange within which the bag 106 is confined.
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A press roll for treating sheet material such as paper and suitable for use in the calender or press section of a paper machine. The roll includes a robust stationary shaft and a shell coaxially surrounding and spaced from the shaft and rotatable with respect thereto. In the gap between the shaft and shell is a sealing structure which surrounds a pressure zone in this gap to seal off this pressure zone, fluid under pressure being supplied to the zone by way of a duct which extends through the shaft, so that the fluid pressure in the pressure zone can be controlled to control deflection of the roll at its shell.
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CROSS-REFERENCE TO RELATED APPLICATION
This application is based upon and claims the benefit of priority of the prior Japanese Patent Application No. 2009-157287 filed on Jul. 1, 2009, the entire contents of which are incorporated herein by reference.
FIELD
The embodiments discussed herein are related to a data transfer apparatus, information processing apparatus and a method of setting data transfer rate.
BACKGROUND
In multi-processor systems functioning as an information processing apparatus (e.g. server system), in which a plurality of processors functioning as central processing units (CPUs) each have a memory space in common, it may be desirable to maintain cache consistency (i.e., consistency of the content of memory stored in cache memory). That is, the content of memory stored in each area of the memory space may be desirable to be the same at every moment when the area of the memory space is accessed from any of the CPUs. Each of the CPUs caches and stores the content of memory when necessary, and thus, in order to guarantee the cache consistency, data transfer may be desirable to be mutually performed among all the CPUs. Further, prior to commencement of the data transfer, a request for the data transfer, which is performed on a command packet basis, is transmitted to all the CPUs by means of a broadcast transfer. Furthermore, in order to guarantee the order of arrivals of the command packets, which have been broadcast transferred in such a manner as described above, it may be desirable for a packet command to be simultaneously arrive at all of transfer destinations, i.e., all of target nodes. Further, crossbar apparatuses, each functioning as a data transfer apparatus which has a function of relaying data transfers between CPUs, are desired to achieve high efficient data transfer.
FIG. 1 is a block diagram illustrating an example of a configuration of a typical multi-processor system. In this example, this multi-processor system is configured to include a plurality of system boards (SBs) 1 - 00 to 1 - 15 (SB 00 to SB 15 ) and a plurality of crossbar (XB) apparatuses 2 - 00 , 2 - 10 , 2 - 20 and 2 - 30 (XB 00 , XB 10 , XB 20 and XB 30 ), which relay data transfers between any two system boards out of the plurality of system boards 1 - 00 to 1 - 15 . Each of the system boards 1 - 00 to 1 - 15 is configured to include a CPU, memory chips and a system controller (SC), but, such a configuration itself is well known to those skilled in the art, and thus, is omitted from illustration in FIG. 1 .
In this example, the system boards 1 - 00 to 1 - 07 and the crossbar apparatuses 2 - 00 and 2 - 10 are installed inside the same enclosure 3 - 0 . Further, the system boards 1 - 08 to 1 - 15 and the crossbar apparatuses 2 - 20 and 2 - 30 are installed inside the same enclosure 3 - 1 . Each of the crossbar apparatuses 2 - 00 and 2 - 10 installed inside the enclosure 3 - 0 is connected to the crossbar apparatuses 2 - 20 and 2 - 30 installed inside the enclosure 3 - 1 via a connection unit 4 , such as a cable assembly.
FIG. 2 is a block diagram illustrating an example of a configuration of an existing crossbar apparatus. In FIG. 2 , for convenience of explanation, only the configuration of the crossbar apparatus 2 - 00 is illustrated, but, the configuration of each of the crossbar apparatuses 2 - 10 , 2 - 20 and 2 - 30 illustrated in FIG. 1 may be the same as or similar to the configuration of the crossbar apparatus 2 - 00 . The crossbar apparatus 2 - 00 is configured to include a buffer unit 21 , output packet selection units 22 and 27 , time difference adjustment units 23 and 25 , and a synchronized distribution unit 26 , which are mutually connected as illustrated n in FIG. 2 .
The buffer unit 21 is configured to include four buffers which are caused to correspond to the system boards 1 - 00 to 1 - 03 to which the crossbar apparatus 2 - 00 is connected, and hold broadcast (BC) commands from the system boards 1 - 00 to 1 - 03 .
The output packet selection units 22 is configured to transfer a BC command held in the buffer unit 21 to crossbar apparatuses to each of which the BC command may be transferred, on the basis of partition configuration determination information provided by an operation management unit 11 , that is, firmware executed by the CPU of the operation management unit 11 , from among the crossbar apparatus 2 - 10 inside the same enclosure 3 - 0 and the crossbar apparatuses 2 - 20 and 2 - 30 inside the different enclosure 3 - 1 . The operation management unit 11 , e.g., the firmware executed by the CPU of the operation management unit 11 , is configured to determine the configurations of individual partitions on the basis of information relating to apparatuses constituting the server system, and output partition configuration determination information, as well as register setting information in accordance with the partition configuration determination information. In this example, the crossbar apparatus 2 - 00 is configured to identify pieces of partition configuration information, i.e., partition IDs, which correspond to the sixteen system boards 1 - 00 to 1 - 15 , respectively. The crossbar apparatus 2 - 00 is configured to cause the output packet selection unit 22 to hold the pieces of partition configuration determination information corresponding to the partition IDs, which are set by the operation management unit 11 , and transfer the BC command to crossbar apparatuses, each being connected to at least a system board having a partition ID equal to one of the partition ID of the system boards 1 - 00 to 1 - 03 connected to the crossbar apparatus 2 - 00 itself. As described below, the crossbar apparatus 2 - 00 is configured to determine a piece of partition configuration information corresponding to an SB, which is a BC-command transmitter, and transfer the BC command to the crossbar apparatus 2 - 10 if the piece of partition configuration determination information indicates a partition P 2 , and transfer the BC command to the crossbar apparatuses 2 - 10 , 2 - 20 and 2 - 30 if the piece of partition configuration determination information indicates a partition P 3 .
The time difference adjustment unit 23 is configured to include a selector 230 and a buffer 231 therein, and BC commands held by the buffer unit 21 and register setting information from the operation management unit 11 , e.g., the firmware executed by the CPU of the operation management unit 11 , are inputted to the buffer 231 and the selector 230 , respectively. The time difference adjustment unit 23 is configured to have four time difference adjustment units which are caused to correspond to the system boards 1 - 00 to 1 - 03 , respectively. The time difference adjustment unit 23 is configured to receive a BC command from the buffer unit 21 . Moreover, in order to cause the BC command to simultaneously arrive at all of target nodes, that is, all of target system boards, the time difference adjustment unit 23 is also configured to output the BC command to the synchronized distribution unit 26 after delaying the broadcast transfer of the BC command by an amount equal to a predetermined delay time by switching the selector 230 in accordance with the register setting information from the operation management unit 11 , which will be described below. In the case where no connection between crossbar apparatuses inside a single enclosure exists, the buffer 231 of the time difference adjustment unit 23 is caused to be bypassed by switching the selector 230 in accordance with the register setting information from the operation management unit 11 . Further, in the case where the delay time is adjusted so as to be equal to a transfer delay between the crossbar apparatuses 2 - 00 and 2 - 10 , the delay time is set to it 1τ (“τ” means a period of one cycle), and in the case where the delay time is adjusted so as to be equal to a transfer delay between the crossbar apparatuses 2 - 00 and 2 - 20 or between the crossbar apparatuses 2 - 00 and 2 - 30 , the delay time is set to 2τ. In the case where the buffer 231 of the time difference adjustment unit 23 is configured by using a ring buffer, in the former case, the pointer of the ring buffer is incremented at intervals of 1τ, and in the latter case, the pointer of the ring buffer is incremented at intervals of 2τ.
The buffer unit 21 , the output packet selection unit 22 and the time difference adjustment unit 23 constitute a local broadcast control (LBC) unit 28 .
A global broadcast control (GBC) unit 29 is configured to output BC commands received from the LBC unit 28 and the crossbar apparatuses 2 - 10 , 2 - 20 and 2 - 30 to target system boards. The GBC control unit 29 is constituted by the time difference adjustment unit 25 , the synchronized distribution unit 26 and the output packet selection unit 27 .
The time difference adjustment unit 25 is configured to include a selector 250 and a buffer 251 , and BC commands transferred from the crossbar apparatuses 2 - 10 , 2 - 20 and 2 - 30 , and register setting information from the operation management unit 11 are inputted to the selector 250 . The time difference adjustment unit 25 is configured to output the BC command from the crossbar apparatus 2 - 10 to the synchronized distribution unit 26 after causing the BC command to be transferred via the buffer 251 by switching the selector 250 in accordance with the register setting information, in order to cause a BC command to simultaneously arrive at all of target system boards. The time difference adjustment unit 25 is further configured to output the BC command from the crossbar apparatus 2 - 20 or the crossbar apparatus 2 - 30 to the synchronized distribution unit 26 . Moreover, thereby, the time difference adjustment unit 25 is configured to perform adjustment so as to make amounts of transfer time resulting from causing the BC commands to be transferred via paths causing various transfer rates to be equal to one another. Moreover, in the case of a model M 1 in FIG. 1 , in which no connection between crossbar apparatuses exists, and further, in the case of a model M 2 in FIG. 1 , in which the crossbar apparatuses 2 - 20 and 2 - 30 do not exist, the buffer 251 of the time difference adjustment unit 25 is caused to be bypassed by switching the selector 250 in accordance with the register setting information from the operation management unit 11 . In the case of a model 3 in FIG. 1 , one or more connections between any two crossbar apparatuses out of the crossbar apparatuses 2 - 00 , 2 - 10 , 2 - 20 and 2 - 30 exist.
The synchronized distribution unit 26 is configured to receive a BC command transmitted from the LBC unit 28 included in either of the crossbar apparatuses 2 - 00 , 2 - 10 , 2 - 20 or 2 - 30 , and distribute the BC command to respective target system boards in synchronization with one another within each partition. The synchronized distribution unit 26 is configured to, include four synchronized distribution units which are caused to correspond to the system boards 1 - 00 to 1 - 03 , respectively, in order to distribute the BC command to respective system boards 1 - 00 to 1 - 03 in synchronization with one another.
The BC commands outputted from the synchronized distribution unit 26 are selected by the output packet selection unit 27 , and the outputted BC commands are inputted to the corresponding system boards 1 - 00 to 1 - 03 . The output packet selection unit 27 is configured to include four output packet selection units which are caused to correspond to the system boards 1 - 00 to 1 - 03 , respectively.
In addition, commands which are processed by the crossbar apparatuses are not only the BC commands. Peer-to-peer (PP) packets may be also caused to transfer through the same crossbar apparatuses. The output packet selection unit 27 has a function of selecting packets, which are to be outputted therefrom, from among the BC command packets and other kinds of packets, such as a peer-to-peer packet.
As illustrated n FIGS. 1 and 2 , the crossbar apparatuses 2 - 00 and 2 - 10 , and the crossbar apparatuses 2 - 20 and 2 - 30 are connected to each other inside the same enclosure, respectively, that is, each of these pairs of crossbar apparatuses is in the condition of a connection inside the same enclosure. In contrast, the crossbar apparatuses 2 - 00 and 2 - 20 , the crossbar apparatuses 2 - 00 and 2 - 30 , the crossbar apparatuses 2 - 10 and 2 - 20 , and the crossbar apparatuses 2 - 10 and 2 - 30 are connected to each other via the connection unit 4 , respectively. The connection unit 4 is provided between the different enclosures 3 - 0 and 3 - 1 , that is, each of these pairs of crossbar apparatuses is in the condition of a connection between different enclosures. Therefore, a transfer rate of each of buses used for the connections between different enclosures is lower than the transfer rate of each of buses used for the connections inside the same enclosure. That is, for example, with respect to three interfaces xb 1 , xb 2 and xb 3 illustrated in FIG. 3 , which are provided by the crossbar apparatus 2 - 00 , the transfer rate of the interface xb 1 may be set to a higher transfer rate, but each of the transfer rates of the interfaces xb 2 and xb 3 may be merely set to a lower transfer rate. Further, a transfer rate which may be realized in the case where one or more connections between crossbar apparatuses inside the same enclosure exist is lower than the transfer rate which may be realized in the case where no connection between crossbar apparatuses inside the same enclosure exists.
As described above, in such a server system as illustrated in FIG. 1 , a transmission performance in the case of the configuration of the connections between different enclosures is lower than the transmission performance in the case of the configuration of the connection inside the same enclosure. In this example, a transfer rate of each of buses used for the connections between different enclosures is set to half of the transfer rate of a bus used for the connection inside the same enclosure. Therefore, in order to cause a BC command to simultaneously arrive at all of target nodes, the broadcast transfer rate in the case of the configuration of the connection inside the same enclosure is necessary to be set to a lower transfer rate the same as the transfer rate of the broadcast transfer rate in the case of the configuration of the connections between different enclosures.
However, in the case where a plurality of partitions is set so as to be closed within an enclosure of a server system, although there are connections between different enclosures of the server system, in each of which no data transfer is performed via the connections between different enclosures are likely to exist. For example, in such a partition configuration as illustrated in FIG. 3 , among partitions P 1 , P 2 and P 3 , which are indicated by a chain double-dashed line, a dotted line and a chain single-dashed line, respectively, each of the partitions P 1 and P 2 is not allowed to transfer BC commands across enclosures. However, in existing methods, regardless of the partition configuration including the partitions P 1 , P 2 and P 3 , each interface between crossbar apparatuses is set to a lower transfer rate. As described above, compared with transfers performed within a single enclosure, in the case where at least a partition covering a plurality of enclosures is likely to exist, setting of a transfer rate thereof is performed taking into account connections between different enclosures. As a result, the broadcast transfer rate is reduced to half the broadcast transfer rate of the case where the broadcast transfer is performed within the single enclosure of a server system.
In order to perform setting change of the broadcast transfer rate while the server system is being operated, it is necessary to clear packets once, which are being processed in each of apparatuses included in the server system, cause the server system to be in a condition where no process is executed, that is, in a suspend condition, and then, perform setting change of the broadcast transfer rate. Therefore, such processing requires complicated control. For this reason, to date, the transfer rate of broadcast transfers performed across different enclosures has been set to a fixed rate.
[Patent Document 1] Japanese Laid-open Patent Publication No. 2000-259542 [Patent Document 2] Japanese Laid-open Patent Publication No. 06-314255
SUMMARY
According to an aspect of an embodiment, a method of setting transfer rate for information processing apparatus having a plurality of processing apparatus including a processor outputting data and connected by one or a plurality of data transfer apparatuses for transferring the data outputted from the processor, the method includes obtaining a dividing information indicating a manner of dividing the information processing apparatus into a plurality of partitions including at least one of the plurality of processing apparatuses, and setting a transfer rate of each partition for broadcasting data to all of the processors included in the plurality of processing apparatuses in each partition based on the obtained dividing information.
The object and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the claims.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention, as claimed.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a block diagram illustrating an example of a configuration of a typical multi-processor system;
FIG. 2 is a block diagram illustrating an example of a configuration of an existing crossbar apparatus;
FIG. 3 is a block diagram illustrating an example of a configuration of a multi-processor system according to an embodiment;
FIG. 4 is a block diagram illustrating an example of a configuration of a crossbar apparatus according to an embodiment;
FIG. 5 is a block diagram illustrating an example of a configuration of an output packet selection unit according to an embodiment;
FIG. 6 is a flowchart illustrating processes of a static setting change according to an embodiment;
FIG. 7 is a diagram illustrating partition configuration information which is set in a partition configuration control register, according to an embodiment;
FIG. 8 is a flowchart illustrating processes of a dynamic setting change according to an embodiment;
FIG. 9 is a diagram illustrating settings of crossbar apparatuses in accordance with each partition configuration, according to an embodiment;
FIG. 10 is a diagram illustrating a content of settings in a configuration control register according to an embodiment; and
FIG. 11 is a block diagram illustrating a structure of enclosures according to another embodiment.
DESCRIPTION OF EMBODIMENTS
In a data transfer apparatus, an information processing apparatus and a method of setting a data transfer rate, which are disclosed here, a broadcast transfer rate is set for each of partitions on the basis of the configuration of the partition. Therefore, for partitions each including therein no connection between enclosures, a higher broadcast transfer rate may be set, compared with a broadcast transfer rate which may be set for partitions each including therein one or more connections between enclosures, and thus, by appropriately partitioning the server system, as a whole, it is possible to realize increase of the broadcast transfer rate.
Hereinafter, embodiments of a method of setting a transfer rate, a data transfer apparatus and an information processing apparatus, according to the present technique, will be described with reference to drawings.
FIG. 3 is a block diagram illustrating an example of a configuration of a multi-processor system as an information processing apparatus according to an embodiment. In FIG. 3 , the same portions as those illustrated in FIG. 1 are denoted by the same reference numerals as those of the portions illustrated in FIG. 1 , and the same portions will be omitted from detailed explanation.
As illustrated in FIG. 3 , a server system is realized by a multi-processor system including therein a plurality of system boards (SB) 1 - 00 to 1 - 15 (SB 00 to SB 15 ), and a plurality of crossbar (XB) apparatuses 32 - 00 , 32 - 10 , 32 - 20 and 32 - 30 (XB 00 , XB 10 , XB 20 and XB 30 ). Each of the system boards 1 - 00 to 1 - 15 is an information processing apparatus including therein a CPU, memory chips and system controllers, and is omitted from illustration in FIG. 3 because such a configuration itself is well known to those skilled in the art.
In this embodiment, the system boards 1 - 00 to 1 - 07 and the crossbar apparatuses 32 - 00 and 32 - 10 are installed inside the same enclosure 33 - 0 . Further, the system boards 1 - 08 to 1 - 15 and the crossbar apparatuses 32 - 20 and 32 - 30 are installed inside the same enclosure 33 - 1 . Each of the crossbar apparatuses 32 - 00 and 32 - 10 , which are installed inside the enclosure 33 - 0 , is connected to the crossbar apparatuses 32 - 20 and 32 - 30 , which are installed inside the enclosure 33 - 1 , via a connection unit 4 , such as a cable assembly.
In addition, for convenience of explanation, this embodiment will be described below by way of an example in which two enclosures are included in a server system; however, needless to say, the present enclosure may be applied to server systems each including two or more enclosures.
FIG. 4 is a block diagram illustrating an example of a configuration of a crossbar apparatus. In FIG. 4 , the same portions as those illustrated in FIG. 2 are denoted by the same reference numerals as those of the portions illustrated in FIG. 2 , and the same portions will be omitted from detailed explanation. In FIG. 4 , for convenience of explanation, only the configuration of the crossbar apparatus 32 - 00 is illustrated, but, obviously, the configuration of each of the crossbar apparatuses 32 - 10 , 32 - 20 and 32 - 30 illustrated in FIG. 3 may be the same as or similar to the configuration of the crossbar apparatus 32 - 00 . The crossbar apparatus 32 - 00 is configured to include therein a buffer unit 21 , output packet selection units 42 and 27 , time difference adjustment units 23 and 25 and a synchronized distribution unit 26 , which are mutually connected as illustrated in FIG. 4 .
The buffer unit 21 is provided with four buffer units, which are caused to correspond to the system boards 1 - 00 to 1 - 03 connected to the crossbar apparatus 32 - 00 , respectively, and holds broadcast (BC) commands from the system boards 1 - 00 to 1 - 03 .
The output packet selection units 42 is configured to transfer a BC command transmitted from one of the system boards 1 - 00 to 1 - 03 and held in the buffer unit 21 to the crossbar apparatus 32 - 10 inside the same enclosure 33 - 0 and/or the crossbar apparatuses 32 - 20 and 32 - 30 inside the different enclosure 33 - 1 , to which it is determined that the BC command is to be transferred on the basis of partition configuration information provided by an operation management unit 41 , e.g., firmware executed by the CPU of the operation management unit 11 . The operation management unit 41 may be configured by employing a processor and the like, which are well known. In this embodiment, the crossbar apparatus 32 - 00 is configured to cause the output packet selection unit 42 to hold partition IDs as pieces of partition configuration information which are caused to correspond to the sixteen system boards 1 - 00 to 1 - 15 , respectively. The partition IDs being used to identify each of partitions. The crossbar apparatus 32 - 00 is configured to transfer the BC command from one of the system boards 1 - 00 to 1 - 03 to one or more crossbar apparatuses, each of which is connected to one or more system boards each having a partition ID equal to the partition ID of a transmitter of the BC command, that is, one of the system boards 1 - 00 to 1 - 03 connected to the crossbar apparatus 32 - 00 itself. As described below, the crossbar apparatus 32 - 00 is configured to transfer a BC command to the crossbar apparatus 32 - 10 in the case where the BC command is transmitted from one of the system boards 1 - 00 to 1 - 03 , which has a piece of partition configuration information indicating a partition P 2 allocated thereto, and the crossbar apparatus 32 - 00 is configured to transfer a BC command to the crossbar apparatuses 32 - 10 , 32 - 20 and 32 - 30 in the case where the BC command is transmitted from one of the system boards 1 - 00 to 1 - 03 , which has a piece of partition configuration information, indicating a partition P 3 allocated thereto.
Further, the output packet selection unit 42 is configured to create and output register setting information which is created on the basis of partition configuration information from the operation management unit 41 , and the output packet selection unit 42 is used for setting registers included in the time difference adjustment units 23 and 25 . Operations performed by the output packet selection unit 42 will be described below in detail. The output packet selection unit 42 functions as a setting means configured to perform setting of broadcast transfer rates on the basis of partition configuration information used for identification of configurations of individual partitions.
The time difference adjustment unit 23 is configured to include a selector 230 and a buffer 231 therein, and BC commands held in the buffer unit 21 and register setting information from the output packet selection unit 42 are inputted to the buffer 231 and the selector 230 , respectively. Four time difference adjustment units 23 are provided, and each of the four time difference adjustment units correspond to one of the system boards 1 - 00 to 1 - 03 , respectively. The time difference adjustment unit 23 is configured to receive a BC command from the buffer unit 21 , and in order to cause the BC command to simultaneously arrive at all of target nodes (target system boards). The time difference adjustment unit 23 is configured to output the BC command to the synchronized distribution unit 26 , which will be described below, after delaying the broadcast transfer of the BC command by an amount equal to a predetermined delay time caused by switching the selector 230 in accordance with the register setting information from the output packet selection unit 42 . In the case of a model M 1 in which no connection between crossbar apparatuses exists, the buffer 231 of the time difference adjustment unit 23 is caused to be bypassed by switching the selector 230 in accordance with the register setting information from the output packet selection unit 42 . Further, in the case of a model M 2 , neither a connection between the crossbar apparatus 32 - 00 and 32 - 20 nor a connection between the crossbar apparatuses 32 - 00 and 32 - 30 exists, and a connection between the crossbar apparatus 32 - 00 and 32 - 10 exists. Further, in the case of a model M 3 , connections from the crossbar apparatus 32 - 00 to the crossbar apparatuses 32 - 10 , 32 - 20 and 32 - 30 are provided. Further, in the case where the predetermined delay time is caused to be equal to an amount of latency between the crossbar apparatuses 32 - 00 and 32 - 10 , the delay time is set to 1τ, and in the case where the predetermined delay time is caused to be equal to an amount of latency between the crossbar apparatuses 32 - 00 and 32 - 10 or between the crossbar apparatuses 32 - 00 and 32 - 20 , the delay time is set to 2τ. In the case where the buffer 231 of the time difference adjustment unit 23 is configured by using a ring buffer, in the former case, the pointer of the ring buffer is incremented at intervals of 1τ, and in the latter case, the pointer of the ring buffer is incremented at intervals of 2τ.
The buffer unit 21 , the output packet selection unit 42 and the time difference adjustment unit 23 constitute a local broadcast control (LBC) unit 48 .
A global broadcast control (GBC) unit 29 is configured to output BC commands received from the LBC control unit 48 and the crossbar apparatuses 32 - 10 , 32 - 20 and 32 - 30 to target system boards. The GBC control unit 29 is constituted by the time difference adjustment unit 25 , the synchronized distribution unit 26 and the output packet selection unit 27 .
The time difference adjustment unit 25 is configured to include a buffer 251 and a selector 250 . BC commands from the crossbar apparatuses 32 - 10 to 32 - 30 and register setting information from the output packet selection unit 42 are inputted to the buffer 251 and the selector 250 , respectively. The time difference adjustment unit 25 is configured to, in order to cause a BC command to simultaneously arrive at all of target system boards, output the BC command from the crossbar apparatus 32 - 10 to the synchronized distribution unit 26 after causing the BC command to be transferred via the buffer 251 by switching the selector 250 in accordance with the register setting information. Further, the time difference adjustment unit 25 is configured to output the BC command from the crossbar apparatus 32 - 20 or the crossbar apparatus 32 - 30 to the synchronized distribution unit 26 to perform adjustment so as to make amounts of transfer time resulting from causing the BC commands to be transferred via paths causing various transfer rates to be equal to one another. Further, in the case where no connection between enclosures exists, and one or more connections between crossbar apparatuses exist, the buffer 251 of the time difference adjustment unit 25 is caused to be bypassed by switching the selector 250 in accordance with register setting information from the output packet selection unit 42 . The time difference adjustment unit 25 is configured to function as a time difference adjustment means for adjusting amounts of transfer delay time of commands from individual system boards (i.e., nodes) on the basis of register setting information as well as the time difference adjustment unit 23 .
The synchronized distribution unit 26 is configured to receive a BC command transmitted from the LBC unit 28 included in either of the crossbar apparatuses 32 - 00 , 32 - 10 , 32 - 20 or 32 - 30 , and distribute the BC command to respective target system boards in synchronization with one another within each partition. The synchronized distribution unit 26 is configured to include four synchronized distribution units which are caused to correspond to the system boards 1 - 00 to 1 - 03 , respectively, in order to distribute the BC command to respective system boards 1 - 00 to 1 - 03 in synchronization with one another.
BC commands selected by the output packet selection unit 27 are inputted to the corresponding system boards 1 - 00 to 1 - 03 . The output packet selection unit 27 is configured to include four output packet selection units which are caused to correspond to the system boards 1 - 00 to 1 - 03 , respectively.
In addition, commands which are processed by the crossbar apparatuses are not only the BC commands. Peer-to-peer (PP) packets may be also caused to transfer through the same crossbar apparatuses. The output packet selection unit 27 has a function of selecting packets, which are to be outputted therefrom, from among the BC command packets and other kinds of packets, such as a peer-to-peer packet.
As illustrated FIGS. 3 and 4 , the crossbar apparatuses 32 - 00 and 32 - 10 , and the crossbar apparatuses 32 - 20 and 32 - 30 are connected to each other inside the same enclosure, respectively. That is, each of these pairs of crossbar apparatuses is in the condition of a connection inside the same enclosure. In contrast, the crossbar apparatuses 32 - 00 and 32 - 20 , the crossbar apparatuses 32 - 00 and 32 - 30 , the crossbar apparatuses 32 - 10 and 32 - 20 , and the crossbar apparatuses 32 - 10 and 32 - 30 are connected to each other via the connection unit 4 , respectively. The connection unit 4 being provided between the different enclosures 33 - 0 and 33 - 1 , that is, each of these pairs of crossbar apparatuses is in the condition of a connection between different enclosures. Thus, a transfer rate of each of buses used for the connections between different enclosures is lower than the transfer rate of each of buses used for the connections inside the same enclosure. That is, with respect to three interfaces xb 1 , xb 2 and xb 3 illustrated in FIG. 3 provided by the crossbar apparatus 32 - 00 , the transfer rate of the interface xb 1 may be set to a higher transfer rate, but each of the transfer rates of the interfaces xb 2 and xb 3 may be merely set to a lower transfer rate, for example. Further, a transfer rate which may be realized in the case where one or more connections between crossbar apparatuses inside the same enclosure exist is lower than that which may be realized in the case where no connection between crossbar apparatuses inside the same enclosure exists.
As described above, in such a server system as illustrated in FIG. 3 , a transmission performance in the case of the configuration of the connections between different enclosures is lower than that in the case of the configuration of the connection inside the same enclosure. In this embodiment, a transfer rate of each of buses used for the connections between different enclosures is set to half of the transfer rate of a bus used for the connection inside the same enclosure. Therefore, in order to cause a BC command to simultaneously arrive at all of target nodes, the broadcast transfer rate in the case of the configuration of the connection inside the same enclosure is necessary to be set to a lower transfer rate the same as the transfer rate of the broadcast transfer rate in the case of the configuration of the connections between different enclosures. However, in the case where a plurality of partitions is set so as to be closed within an enclosure, although there are connections between different enclosures of the server system, in each of which no data transfer is performed via the connections between different enclosures are likely to exist. For example, in such a partition configuration as illustrated in FIG. 3 , among partitions P 1 , P 2 and P 3 , which are indicated by a chain double-dashed line, a dotted line and a chain single-dashed line, respectively, each of the partitions P 1 and P 2 is not allowed to transfer BC commands across enclosures.
Therefore, in this embodiment, by causing the output packet selection unit 42 to output register setting information to each of the time difference adjustment units 23 and 25 on the basis of partition configuration information from the operation management unit 41 , a broadcast transfer rate is set for each partition on the basis of a partition configuration thereof. Thus, in the case where no connection between enclosures exists in a certain partition, the above-described method enables a broadcast transfer to be performed within the partition at a higher transfer rate than a transfer rate of a broadcast transfer which is performed within a partition including therein one or more connections between enclosures, and thus, the above-described method leads to an increase of the broadcast transfer rate. As a result, depending on a partition configuration, it is possible to improve a throughput of a broadcast transfer to a greater degree than before. Further, according to this embodiment, in the case of a partition configuration in which no connection between enclosures exists and one or more connections between crossbar apparatuses exist, it is also possible to improve a throughput of a broadcast transfer of a server system to a great extent. Moreover, differing from existing methods, the broadcast transfer rates are not statically set, but are set on the basis of the configurations of individual partitions, and further, may be also changed in conjunction with changing of the partition configuration of the server system in operation.
FIG. 5 is a block diagram illustrating an example of a configuration of the output packet selection unit 42 . The output packet selection unit 42 is configured to include a register setting interface 421 , a partition configuration control register 422 , a partition configuration determination unit 423 , a time difference adjustment control unit 424 and a configuration control register 425 , which are serially connected, as illustrated in FIG. 5 . In accordance with a process procedure described below, the output packet selection unit 42 changes the transfer rates of broadcast transfers performed between crossbar apparatuses by notifying the necessity or unnecessity of latency to be performed by the buffers 231 and 251 to the time difference adjustment units 23 and 25 , respectively, in accordance with partition configuration information notified from the operation management unit 41 .
The partition configuration is determined by the configuration determination unit 423 inside the output packet selection unit 42 . The determination of the partition configuration itself may be performed in the same way as or in a way similar to that performed by the operation management unit 11 of an existing crossbar apparatus illustrated in FIG. 2 . The partition configuration determination unit 423 recognizes the partition configuration by comparing partition IDs of the sixteen system boards (SBs), and further, the partition configuration determination unit 423 changes broadcast transfer rates for individual partitions in accordance with the recognized partition configuration by means of either a static setting change which is performed under the condition where the server system is powered off before being powered on, or a dynamic setting change which is performed at the timing when a dynamic reconfiguration (DR) is performed immediately after the server system is powered on in this embodiment. The DR is a technology which allows hardware resources, such as processors, memory chips, and input output (IO) devices, to be added or deleted without halting an operating system (OS) installed in the server system. When performing the configuration change by using the DR, crossbar apparatuses causes the server system to operate in a suspend condition.
FIG. 6 is a flowchart illustrating processes of a static setting change. Firstly, in step S 1 , a crossbar apparatus to which the output packet selection unit 42 belongs (which is the crossbar apparatus 32 - 00 , in this embodiment) is caused to be in a condition where no packet communication via this crossbar apparatus is performed. More specifically, the operation management unit 41 performs setting so as to cause the server system to be in a power-off condition. Subsequently, in step S 2 , partition configuration information from the operation management unit 41 is set in the partition configuration control register 422 via the register setting interface 421 .
FIG. 7 is a diagram illustrating partition configuration information which is set in the partition configuration control register 422 . In the partition configuration control register 422 of each of the crossbar apparatuses 32 - 00 , 32 - 10 , 32 - 20 and 32 - 30 , partition configuration information from the operation management unit 41 is set. In this embodiment, partition IDs (SBxx_PAR_IDs), which correspond to sixteen system boards (SBs), that is, SBxx (XX=00 to 15), respectively, are held in the partition configuration control register 422 as partition configuration information.
In step S 3 , from the content of setting information held in the partition configuration control register 422 , the partition configuration determination unit 423 identifies all partitions, and for each of the identified partitions, determines whether one or more connections between crossbar apparatuses inside the same enclosure exist, or not, and whether one or more connections between different enclosures exist, or not. As a result of the determination having been made in step S 3 , in the case where no connection between crossbar apparatuses inside the same enclosure exists, and no connection between different apparatuses exists, the process procedure proceeds to step S 4 . Further, in the case where one or more connections between crossbar apparatuses inside the same enclosure exist, and no connection between different apparatuses exists at step S 4 , the process procedure proceeds to step S 5 , and in the case where one or more connections between crossbar apparatuses inside the same enclosure exist, and one or more connections between different apparatuses exist, the process procedure proceeds to step S 6 . In each of steps S 4 , S 5 and S 6 , the partition configuration determination unit 423 notifies the time difference adjustment control unit 424 of the determination result.
Upon receipt of the notification from the partition configuration determination unit 423 , the time difference adjustment control unit 424 sets the current partition configuration and information relating to usages of the buffer 231 and the buffer 251 in the configuration control register 425 . In this embodiment, in the case where a selection indication XBy_SEL_ENB (y=2 or 3) from the partition configuration determination unit 423 is valid in step S 6 , the time difference adjustment control unit 424 outputs the following setting: MODEL [1:0]=“1x”, BUF 1 =1, BUF 2 =1, which is equivalent to the setting of the model M 3 . Otherwise, in the case where a selection indication XB 1 _SEL_ENB is valid in step S 5 , the time difference adjustment control unit 424 outputs the following setting: MODEL[1:0]=“01”, BUF 1 =1, BUF 2 =0, which is equivalent to the setting of the model M 2 . In the case where neither of the former condition nor the latter condition is satisfied, and further, in the case where a selection indication XB 0 _SEL_ENB is valid in step S 4 , the time difference adjustment control unit 424 outputs the following setting: MODEL[1:0]=“00”, BUF 1 =0, BUF 2 =0, which is equivalent to the setting of the model M 1 . Here, BUF 1 designates a setting for the buffer 231 included in the time difference adjustment unit 23 , and, for example, BUF 1 =0 designates a setting which directs the time difference adjustment unit 23 to cause BC commands to bypass the buffer 231 , and BUF 1 =1 designates a setting which directs the time difference adjustment unit 23 to cause BC commands to be transferred via the buffer 231 . Further, BUF 2 designates a setting for the buffer 251 of the time difference adjustment unit 25 , and, for example, BUF 2 =0 designates a setting which directs the time difference adjustment unit 25 to cause BC commands to bypass the buffer 251 , and BUF 1 =1 designates a setting which directs the time difference adjustment unit 25 to cause BC commands to be transferred via the buffer 251 .
By using these pieces of setting information, the configuration control register 425 directs the selector 230 of the time difference adjustment unit 23 and the selector 250 of the time difference adjustment unit 25 to select a latency circuit, such as the buffer 231 and the buffer 251 , respectively, each of which is, for example, a ring buffer and the like, and thereby, the configuration control register 425 changes the transfer rates of broadcast transfers performed across the crossbar apparatuses. With respect to a certain partition, for which it is determined that, actually, no connection between crossbar apparatuses inside the same enclosure exists, and further, no connection between different enclosures exists, a setting equivalent to the setting of the model 1 is performed even though the configuration of the partition is set to the model 2 or the model 3 . Further with respect a certain partition, for which it is determined that one or more connections between crossbar apparatuses inside the same enclosure exist and further, no connection between different enclosures exists, a setting equivalent to the setting of the model 2 is performed. Moreover with respect to a certain partition, for which it is determined that one or more connections between crossbar apparatuses inside the same enclosure exist, and further one or more connections between different enclosures exist, a setting equivalent to the setting of the model 3 is performed.
In step S 7 , the server system is set to a power-on condition, and then, the processes of the static setting change are terminated.
In addition, as illustrated by a dotted line in FIG. 5 , the setting of the configuration control register 425 from the operation management unit 41 may be performed, not via the time difference adjustment control unit 424 , but via the register setting interface 421 .
In control of the server system, in the case where the system-board sides require the partition configuration information, the operation management unit 41 may perform setting system controllers included in the individual system boards. Further, in the case where a plurality of selection indications XBx_SEL_ENBs which are inputted to the time difference adjustment control unit 424 are outputted, a setting equivalent to the setting of the largest scaled partition among the partitions indicated by the selection indications may be performed.
For example, in the case illustrated in FIG. 3 where in such a configuration as connections between different enclosures, the crossbar apparatuses 32 - 00 and 32 - 10 are set as a first partition, and the crossbar apparatuses 32 - 20 and 32 - 30 are set as a second partition, communications between different enclosures (i.e., communications between the crossbar apparatus XB 00 and the crossbar apparatus XB 20 and between the crossbar apparatus XB 00 and the crossbar apparatus XB 30 , and communications between the crossbar apparatus XB 10 and the crossbar apparatus XB 20 and between the crossbar apparatus XB 10 and the crossbar apparatus XB 30 ) are not performed. In such a manner as described above when it is determined by the partition configuration determination unit 423 that no connection between different enclosures exists, the broadcast transfer rate may be set to a higher transfer rate in this embodiment.
The crossbar apparatus 32 - 00 illustrated in FIG. 4 transfers BC commands to interfaces of crossbar apparatuses to each of which at least a system board (SB) having the same partition ID as the partition ID of one of the system boards (SB 00 to SB 03 ) which are connected to the crossbar apparatus 32 - 00 is connected. In FIG. 5 , in the case where either of selection indications XB 2 _SEL_ENB[i] (i=0, 1, 2 and 3) or either of selection indications XB 3 _SEL_ENB[i] (i=0, 1, 2 and 3) is valid for a certain partition, it is determined that the partition is configured to cover the two enclosures, and thus, the transfer rate of broadcast transfers performed via connections between any two crossbar apparatuses out of all the crossbar apparatuses belonging to the partition is set to a lower transfer rate.
FIG. 8 is a flowchart illustrating processes of a dynamic setting change. Firstly in step S 11 , the server system is set to a power-on condition. Next in step S 12 , partition configuration information from the operation management unit 41 is set in the partition configuration control register 422 via the register setting interface 421 . In step S 13 , the server system executes processes in operation, and in step S 14 , along with the commencement of the dynamic reconfiguration (DR), the crossbar apparatus 32 - 00 causes the server system to be in a suspend condition. That is, a suspend command in response to a BC command is transmitted from the crossbar apparatus 32 - 00 to system controllers of all the system boards, and upon completion of processes in execution, each of the system controllers is in a suspend-release waiting condition.
Next, along with operations for addition and deletion of system boards, and the like, the partition configuration is changed, and in step S 15 , the changed partition configuration from the operation management unit 41 is set in the partition configuration control register 422 included in the output packet selection unit 42 . In addition, it is also possible to implement functions so that partition configuration information is transmitted to all the system controllers in advance before causing each of the system controllers to be in a suspend condition, and the transmitted partition configuration information causes only updating inside each of the crossbar apparatuses to be performed during a period of time while the suspend condition is being continued. After completion of changing the partition configuration, and before resumption of operations performed by the server system, in step S 16 , from the content of setting information held in the partition configuration control register 422 , the partition configuration determination unit 423 identifies all partitions, and for each of the identified partitions, the partition configuration determination unit 423 determines whether one or more connections between crossbar apparatuses inside the same enclosure exist or not, and whether one or more connections between different enclosures exist or not. As a result of the determination having been made in step S 16 , in the case where no connection between crossbar apparatuses inside the same enclosure exists, and no connection between different apparatuses exists, the process procedure proceeds to step S 17 , in the case where one or more connections between crossbar apparatuses inside the same enclosure exist, and no connection between different apparatuses exists, the process procedure proceeds to step S 18 . Moreover, at step S 18 , in the case where one or more connections between crossbar apparatuses inside the same enclosure exist and one or more connections between different apparatuses exist, the process procedure proceeds to step S 19 . In each of steps S 17 , S 18 and S 19 , the partition configuration determination unit 423 notifies the time difference adjustment control unit 424 of the determination result. Processes performed in steps S 17 , S 18 and S 19 are the same as or similar to those performed in steps S 4 , S 5 and S 6 .
By using these pieces of information, the configuration control register 425 directs the selector 230 of the time difference adjustment unit 23 and the selector 250 of the time difference adjustment unit 25 to select a latency circuit, such as the buffer 231 and the buffer 251 , respectively, each of which is, for example, a ring buffer and the like. Moreover, thereby, the partition configuration determination unit 423 changes the transfer rates of broadcast transfers performed across the crossbar apparatuses. With respect to a certain partition, for which it is determined that, actually, no connection between crossbar apparatuses inside the same enclosure exists, and further, no connection between different enclosures exists, a setting equivalent to the setting of the model 1 is performed, even though the configuration of the partition is set to the model 2 or the model 3 . Further, with respect a certain partition, for which it is determined that one or more connections between crossbar apparatuses inside the same enclosure exist, and further, no connection between different enclosures exists, a setting equivalent to the setting of the model 2 is performed. Moreover, with respect to a certain partition, for which it is determined that one or more connections between crossbar apparatuses inside the same enclosure exist, and further, one or more connections between different enclosures exist, a setting equivalent to the setting of the model 3 is performed.
In step S 20 , the suspend condition of the server system is released along with completion of the DR, and then, the processes of the dynamic setting change are terminated.
FIG. 9 is a diagram illustrating settings of crossbar apparatuses in accordance with each configuration of partitions according to this embodiment. In this embodiment, the partition configuration determination unit 423 performs settings from a result of determination with respect to the configuration of a partition which is equivalent to the configuration of the largest scaled model M 3 as described below. In FIG. 9 , “XB 2 / 3 ” designates XB 2 or XB 3 .
In the case of a partition configuration equivalent to the configuration of the model M 1 , since it is determined that a target partition is configured to be closed within a crossbar apparatus, in order to improve an amount of latency, settings are performed so that the BC commands are transferred by bypassing the buffer 231 of the time difference adjustment unit 23 . As a result, the total amount of latency of SB→XB (→XB)→SB is equal to an amount of latency resulting from setting the broadcast transfer rate to the highest rate.
In the case of a partition configuration equivalent to the configuration of the model M 2 , since it is determined that a target partition is configured to cover the crossbar apparatuses 32 - 00 and 32 - 10 within the same enclosure 33 - 0 , in order to perform adjustment for delaying the broadcast transfer by an amount equivalent to a transfer delay time between the crossbar apparatuses 32 - 00 and 32 - 10 , settings are performed so that the BC commands are transferred via the buffer 231 of the time difference adjustment unit 23 , and further, the BC commands are transferred by bypassing the buffer 251 of the time difference adjustment unit 25 . As a result, the total amount of latency of SB→XB (→XB)→SB is equal to an amount of latency resulting from setting the broadcast transfer rate to a higher transfer rate.
In the case of a partition configuration equivalent to the configuration of model M 3 , since it is determined that a target partition is configured to cover the enclosures 33 - 0 and 33 - 1 , settings are performed so that the BC commands are transferred via the buffer 231 of the time difference adjustment unit 23 in order to perform adjustment for delaying the broadcast transfer by an amount equivalent to a transfer delay time between the crossbar apparatuses 32 - 00 and 32 - 20 or between the crossbar apparatuses 32 - 00 and 32 - 30 , and further, settings are performed so that the BC commands are transferred via the buffer 251 of the time difference adjustment unit 25 in order to perform adjustment for delaying the broadcast transfer by an amount equivalent to an amount of time resulting from subtracting a transfer delay time between the crossbar apparatuses 32 - 00 and 32 - 10 from a transfer delay time between the crossbar apparatuses 32 - 00 and 32 - 20 or between the crossbar apparatuses 32 - 00 and 32 - 30 . As a result, the total amount of latency of SB→XB (→XB)→SB is equal to an amount of latency resulting from setting the broadcast transfer rate to a lower transfer rate.
As described above, according to this embodiment, it is possible to perform settings equivalent to those of a minimum scaled model which enables realization of a target partition from partition configuration information stored in the partition configuration determination unit 423 inside the output packet selection unit 42 . In a server system configured to include one or more connections between different enclosures, which degrade transmission capability, partitions, which are configured not to include any connections between crossbar apparatuses, enable realization of broadcast transfers without decreasing the transfer rate thereof.
In addition, since the buffer 231 of the time difference adjustment unit 23 includes four buffers, which are caused to correspond to receiving side system boards, respectively, by performing setting of the four buffers of the buffer 231 independently, any partition which is configured not to include connections between crossbar apparatuses is constantly allowed to perform broadcast transfers with a minimum latency.
FIG. 10 is a diagram illustrating a content of settings of the configuration control register 425 included in the output packet selection unit 42 . In the configuration control register 425 , a partition configuration MODEL [1:0] and buffer settings BUF 1 and BUF 2 are set. For example, an example of settings equivalent to those of the model M 1 is “hX0000000”, an example of settings equivalent to those of the model M 2 is “hX0000001”, and an example of settings equivalent to the model M 3 is “hX0000002”.
FIG. 11 is a block diagram illustrating a structure of enclosures according to another embodiment. In FIG. 11 , the same portions as those illustrated in FIG. 3 are denoted by the same reference numerals as those of the portions illustrated in FIG. 3 , and are omitted from detailed explanation.
In FIG. 11 , the operation management unit 41 is provided inside the enclosure 33 - 0 , one or more crossbar apparatuses 32 inside the enclosure 33 - 0 are connected to one or more crossbar apparatuses 32 inside the enclosure 33 - 1 via the connection unit 4 such as a cable assembly. The operation management unit 41 is also provided inside the enclosure 33 - 1 . For example, the enclosure 33 - 0 may be a basic enclosure, and the enclosure 33 - 1 may be an expanded enclosure.
In addition, the operation management units 41 may be obviously provided outside the enclosures 33 - 0 and 33 - 1 , respectively.
All examples and conditional language recited herein are intended for pedagogical purposes to aid the reader in understanding the embodiment and the concepts contributed by the inventor to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions, nor does the organization of such examples in the specification relate to a illustrating of the superiority and inferiority of the embodiment. Although the embodiments of the present invention have been described in detail, it should be understood that the various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the invention.
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A method of setting transfer rate for information processing apparatus having a plurality of processing apparatus including a processor outputting data and connected by one or a plurality of data transfer apparatuses for transferring the data outputted from the processor, the method includes obtaining a dividing information indicating a manner of dividing the information processing apparatus into a plurality of partitions including at least one of the plurality of processing apparatuses, and setting a transfer rate of each partition for broadcasting data to all of the processors included in the plurality of processing apparatuses in each partition based on the obtained dividing information.
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BACKGROUND OF THE INVENTION
This invention relates to a heat-generating device for molds of injection molding machines and, more specifically, to a tip heater for use on a runnerless injection molding heating probe.
Conventional heat-generating devices commonly called torpedoes or probes for runnerless injection molding are disclosed in U.S. Pat. Nos. 4,516,927 and 4,643,664 to Yoshida. These patents disclose pointed heat-generating devices in which a heat-generating wire disposed within a bore in a non-processed cylindrical material is joined to the non-processed cylindrical material by fusion to form an alloy. The alloy portion is then machined to form a point. The alloy point is commonly called a "tip heater". Tip heaters of the type disclosed by Yoshida are relatively easy to construct; however, tip heaters constructed by fusing the heating wire to a non-processed cylindrical material and then machining the alloy to a point have several disadvantages. Alloy materials which form the tip of conventional tip heaters have unpredictable hardness due to the fusion process by which the alloy is formed. When molding abrasive resins, it is common for alloy point tip heaters to fail due to wear at the alloy point. A need therefore exists for a heat generating device which has a tip heater having a known hardness to match the abrasive environment in which the device is to be used.
Another disadvantage of alloy pointed tip heaters is the tendency for the alloy material to exhibit microscopic porosity to molten polymer resins. Alloy points often have microscopic pores through which molten resin can enter into the body of the heating probe resulting in fouling of the probe and associated equipment over time. A need therefore exists for a probe having a tip heater which is not susceptible to resin porosity.
Another disadvantage of alloy pointed tip heaters is that alloy pointed tip heaters are difficult to repair once the alloy portion becomes damaged due to wear from molding abrasive resins, accidents, or abuse of the molding equipment. The repair difficulty is due to the uncertainty of determining exactly where the wire is fused to the unprocessed material. Since the exact location of the alloy-to-wire junction is unknown, it is difficult to know how much of the tip must be removed in order to effect repairs. A need, therefore, exists for a tip heater for use during runnerless injection molding which provides a pointed portion in which the wire to point junction is known thereby allowing for easy tip heater repair.
Accurate placement of wire to point junction also greatly improves consistency of thermal performance guaranteeing identical behavior between multiple probes in a mold.
SUMMARY OF THE INVENTION
It is an object of this invention to provide a tip heater for attachment to a heating probe used for runnerless injection molding in which the tip heater point has a known hardness. It is also an object of this invention to provide a tip heater which is not subject to resin porosity.
It is also an object of this invention to provide a tip heater having a known heating wire and point juncture which facilitates tip heater repair.
To achieve the foregoing and in accordance with the purposes of the present invention as embodied and broadly described herein, the present invention provides a tip heater attached to a heating probe having a metal body having a front end, a back end, and a longitudinal bore, the probe utilized in runnerless injection molding machines for opening and closing mold gates by ON-OFF switching of the tip heater.
The tip heater comprises a generally conically shaped tip, a cap, a heating wire, and an insulating material. The generally conically shaped tip is attached to the front end of the metal body. The tip has a front and a back end, and a first and a second longitudinal bore. The first longitudinal bore of the tip is aligned with the longitudinal bore of the metal body. The cap has a socket and is attached to the front end of the tip. The socket is aligned with the second longitudinal bore of the tip. The heating wire has a first end and a second end and is disposed in the bore of the metal body and in the first and second longitudinal bores of the tip. The first end of the heating wire is attached to the cap at the socket and the second end of the heating wire is electrically connectable to an ON-OFF switch such that the heating wire heats the cap when the switch is ON and the heating wire does not heat the cap when the switch is OFF. The insulating material is disposed between the bore of the metal body and the heating wire and between the bores of the tip and the heating wire.
In yet another embodiment of this invention, the tip heater is attached to a heating probe having a metal body having a front end, a back end and a longitudinal bore, the probe utilized in runnerless injection molding machines for opening and closing mold gates by ON-OFF switching of the tip heater. The tip heater comprises a generally conically shaped tip, a heating wire, and an insulating material. The generally conically shaped tip is attached to the front end of the metal body. The tip has a pointed front end, a back end, a recess and a socket. The socket is aligned with the recess, and the recess is aligned with the longitudinal bore of the metal body. The heating wire is disposed in the bore of the metal body and disposed in the recess of the tip. The heating wire has a first end and a second end. The first end of the heating wire is attached to the tip at the socket. The second end of the heating wire is electrically connectable to an ON-OFF switch such that the heating wire heats the tip when the switch is ON and the heating wire does not heat the tip when the switch is OFF. The insulating material is disposed between the bore of the metal body and the heating wire, and between the recess of the tip and the heating wire.
Another aspect of this invention provides a method for constructing a tip heater attached to a heating probe.
Yet other aspects of this invention provide methods for repairing tip heaters attached to heating probes.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings, which are incorporated in and form a part of the specification, illustrate the embodiments of the present invention and, together with the description serve to explain the principles of the invention.
In the drawings:
FIG. 1 is a partially cut-away sectional view of a heating probe with an attached tip heater.
FIG. 1A is an enlarged, partially, cut-away sectional view of the tip and cap of the tip heater illustrated in FIG. 1.
FIG. 2 is a sectional view of the probe illustrated in FIG. 1 taken along line 2--2.
FIG. 3 is a partially cut-away enlarged sectional view of the tip heater showing a device under construction.
FIG. 4 is a partially cut-away enlarged sectional view of the completed tip heater.
FIG. 5 is a cut-away enlarged sectional view of one embodiment of the tip heater cap and tip.
FIG. 6 is a cut-away enlarged sectional view of another embodiment of the tip heater tip.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
A tip heater 50 of the present invention is shown generally in the circled area in FIG. 1 attached to a probe 10 also shown generally in FIG. 1. Tip heater 50 is comprised of a generally conically shaped tip 16, a heating wire 21, insulating material 23, and a cap 30. Probe 10 has generally a cylindrical metal body 11 and a head 15.
Metal body 11 has a front end 12, a back end 13, and a longitudinal bore 14. The back end 13 of body 11 is attached to head 15. Head 15 is positioned such that metal body 11 is disposed within mold resin channel 101 as shown in FIGS. 1. Head 15 is shown in FIG. 1 having resin channels 25 shown in FIG. 2 which are positioned in fluid communication with resin channels 102 of a manifold 100. The front end 12 of body 11 is attached to tip heater 50. Tip heater 50 includes a generally conical tip 16 having a first longitudinal bore 17, a second longitudinal bore 18, a front end 19, and a back end 20 as shown in detail in FIG. 1A. Back end 20 is attached to front end 12 of body 11. Front end 19 is attached to cap 30. Cap 30 has a generally conical shape and a socket 32. Heating wire 21 is disposed within bores 14, 17, and 18 and has a front end 24. Front end 24 of wire 21 is attached to cap 30 at socket 32. The back end of wire 24 is electronically connectable to an ON-OFF switch (not shown). Insulating material 23 such as but not limited to magnesium oxide or a ceramic sleeve is disposed within bores 14, 17, and 18 to separate and thermally insulate heating wire 21 from metal body 11 and from tip 16. Electrical current flowing through heating wire 21 heats cap 30. An electrical return can be attached to the mold or to the probe to provide electrical continuity. The flow of electricity through heating wire 21 is controlled by an ON-OFF switch such that when the ON-OFF switch is ON, the electricity flow through wire 21 heats cap 30 and when the ON-OFF switch is OFF, electricity does not flow through wire 21 and cap 30 is not heated. Cylindrical metal body 11 can also have one or more body heaters (not shown in the drawings) as are well known in the art to maintain the molten state of resin within channel 101 and within head channels 25 during each injection molding cycle.
Probe 10 is positioned within resin channel 101 such that molten resin from an injection molding machine can flow through manifold channel 102, through head channel 25, into channel 101, through gate 103, and into a cavity 104 in the mold.
Tip heater 50 is utilized by an ON-OFF switch electrically connected to wire 21 being switched ON resulting in heating wire 21 becoming hot. As a result, cap 30 becomes hot, melting solidified resin in gate 103. Molten resin under pressure then flows through channels 102, 25, 101, gate 103, and into the mold 104. Anytime after flow through the gates is established, the ON-OFF switch attached to wire 21 is switched OFF causing wire 21 to cease heating. Cooling lines 200 in the mold solidify resin in the areas adjacent tip 16 and cap 30 thereby closing gate 103 yet allowing resin in channels 101, 25, and 102 to remain molten. Closing gate 103 allows the mold to be opened and the molded part to be removed without molten resin flowing through gate 103, and without excess resin waste attaching to the molded part from gate 103, thus, permitting runnerless molding to occur.
Over time, the flow of molten resin through passages 101 and gate 103 can cause tip 16 and cap 30 to abrade and eventually improperly open and close gate 103. Probe tip heaters can also become damaged through accident or abuse often resulting in deformation of the tip heater point or separation of the heating wire from the heater point resulting in improper gate closure. Alloy pointed tip heaters are not easily repaired and often necessitate replacement of the entire heating probe when the alloy point is damaged. In addition, if between molding operations, probe users notice that a point on a particular alloy pointed tip heater is not withstanding the wear due to abrasive resin environments, an entire new heating probe must be purchased without any assurance that the alloy point on the new probe tip heater will withstand the abrasiveness of the resin environment that the new probe is to be used in. The instant invention solves this problem by providing a tip heater with a pointed cap which is constructed to be repaired and which has a point with a known hardness to match the resin that the tip heater is to be used in.
The method for constructing a tip heater of this invention is herein described with reference to FIG. 3. Front end 12 of metal body 11 is joined to tip 16 by welding or brazing at the adjacent peripheries 40. Wire 21 is then disposed within bores 14, 17, 18. An unprocessed cap 30U of a material having a known hardness and having a socket 32 is then placed adjacent tip 16 such that front end 24 of wire 21 is disposed in socket 32. Unprocessed cap 30U is then joined to tip 16 by welding or brazing at adjacent peripheries 41 and then insulating material 23 is packed between bores 14, 17, 18, and wire 21. The unprocessed cap is then swaged to secure the front end 24 of wire 21 within socket 32 and is then machined to a point to form cap 30 as shown in FIGS. 1, 1A, and 4. The invention thus provides a repairable tip heater which overcomes the problem of unknown point hardness associated with alloy pointed tip heaters by providing a pointed cap having known hardness. Additionally, since the point is not constructed by fusion to form an alloy, the tip heater does not suffer from resin microporosity problems.
The cap, as shown in FIG. 4, can be easily repaired by the method of cutting through fused circumference 41 or grinding cap 30 off to the known cap-wire juncture at circumference 41. A repair cap is then attached to wire 21, joined to tip 16, and ground to a point, thus, eliminating the need to replace the entire device 10 every time cap 30 is damaged. Repair is made easy by this invention since the problem of unknown wire-alloy juncture, which is associated with alloy pointed tip heaters, is eliminated.
If the tip 16 is damaged, the tip 16 can be repaired by cutting through area 40 and removing tip 16, wire 21, and insulating material 23 from body 11. A repair wire which is either a new wire 21 or the old wire 21 is then inserted into body 11, a new repair tip 16 is joined to body 11 at adjacent peripheries 40, a new, unprocessed cap of a material having a known hardness is attached to the repair wire and is joined to the repair tip. Insulating material is then packed between the repair heating wire and the metal body and between the heating wire and the repair tip. The unprocessed cap is then machined to a point.
Another embodiment of the invention is shown in FIG. 5 where, in lieu of swaging the heating wire to the caps, the heating wire 21A has a threaded first end 24A attached to a threaded socket 32A in cap 30A. Cap 30A shown in FIG. 5 can be repaired by cutting through joined circumference 41, unscrewing cap 30A from wire 21A, re-attaching a new repair threaded cap to wire 21A and joining the repair cap to tip 16.
Another embodiment of the invention is shown in FIG. 6. The tip heater shown in FIG. 6 is comprised of a generally conical shaped tip 16B, a heating wire 21, and insulating material 23. Tip 16B has a point 64, a back end 63, a recess 60, and a socket 61. Back end 13 is joined to the metal body of a probe having a longitudinal bore (not shown). Heating wire 21 has a first end 24 attached to tip 16B at socket 61 and a second end electrically connectable to an ON-OFF switch (not shown). Insulating material 23 is disposed between the bore of the probe metal body and heating wire 21 and between recess 60 of tip 16B and heating wire 21. Point 64 is heated when the ON-OFF switch is ON and is not heated when the ON-OFF switch is OFF. To repair this embodiment of the tip heater, the entire tip can be removed by cutting through the area attaching tip 16B to a metal body (not shown in FIG. 6) and removing wire 21 and insulating material 23 from device 10. A repair wire is then inserted into the probe metal body and into the recess and socket of a repair tip. The repair tip is then joined to the metal body, insulating material is packed between the repair wire and the metal body and between repair wire and the repair tip, and the tip is swaged to compress the insulating material and to secure the repair wire within the socket of the repair tip.
The joining of cylindrical metal bodies to tips and tips to caps can be accomplished by conventional welding, fusion welding, laser welding, by brazing, by an electron beam, or by any other means well known in the art so long as the joining of cylindrical bodies to tips and tips to caps, allows tips and/or caps to be removed and replaced by new repair tips and/or caps as needed. The attachment of heating wires to tips or wires to caps can be accomplished as described herein by swaging or by threading as well as by cryogenic shrink fitting. Additionally, the heat-generating device described herein has been described as having a head portion located below the manifold. However, it is within the scope of this invention that the tip heater can be utilized with other probe types such as but not limited to probes having heads positioned within manifolds or probes having heads positioned on opposite sides of manifolds from the tip heaters.
Thus, the invention provides a tip heater for use on a heating probe used for runnerless injection molding which has a point of known hardness which is not subject to resin porosity and which is easily repaired.
While the preferred embodiments have been fully described and depicted for the purposes of explaining the principles of the present invention, it will be appreciated by those skilled in the art that modification and changes may be made thereto without departing from the scope of the invention set forth in the appended claims.
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This invention relates to a tip heater for a runner-less injection molding heating probe and to methods for constructing and repairing the same. The tip heater comprises a generally conical shaped tip, a heating wire, insulating material, and a cap. The tip heater is attached to a heating probe positioned within resin channels communicated to mold cavities. The tip heater is characterized by removable and replaceable tips and/or caps which allow the tip heater to be repaired.
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[0001] The invention provides a method for targeted transgenesis using the Rosa26 locus. Suitable nucleotide acid sequences and vectors for the targeted transgenesis and recombinase mediated transgenesis are provided. The Rosa26 locus proved to be a suitable integration site allowing strong and predictable expression of inserted transgenes carrying exogenous promoters.
BACKGROUND OF THE INVENTION
[0002] The generation of transgenic mice by nuclear injection of purified DNA into fertilized eggs is a widely used approach for studying gene or promoter function in vivo. However, the level and pattern of expression often varies strongly depending on copy number, configuration, and integration site of the transgene. In addition, founder mice occasionally do not transmit the transgene. Thus, a number of different founders need to be generated and tested in order to identify a useful strain, which is a laborious and time-consuming undertaking (Bradley et. al., Nature Genet., 14:121-123 (1996); Jasin et al., Proc. Natl. Acad. Sci. USA, 93:8804-8808 (1996); Dobie et al., Trends Genet., 13:127-130 (1997); Garrick et. al., Nature Genet., 18:56-59 (1998), Al-Shawi et al., Mol. Cell. Boil. 10:1192-1198 (1990)).
[0003] To overcome these limitations, homologous recombination in embryonic stem cells has been used to produce mice carrying a single copy of the transgene integrated into a predetermined site of the genome (Shaw-White et al., Transgenic Res.; (1):1-13 (1993); Bronson et al., Proc. Natl. Acad. Sci. USA, 93(17:9067-72 (1996); Hatada et al., J. Biol., Chem., 274(2):948-55 (1999); Vivian et al., Biotechniques, 27(1):154-62 (1999); Evans et al., Physiol. Genomics, March 13, 2(2):67-75 (2000); Cvetkovic et al., J. boil. Chem., 275(2):1073-8 (2000); Guillot et al., Physiol. Genomics, March 13, (2):77-83 (2000); Magness et al., Blood, 95(11):3568-77 (2000); Misra et al., BMC Biotechnol., 1(1):12 (2001); Minami et al., Blood, 100(12):4019-25 (2002); Tang et al., Genesis, 32(3):199-202 (2002)). In these studies, the ubiquitous Hprt locus was more or less successfully used for ‘targeted transgenesis’. Insertion of a lacZ gene under the control of the polyoma enhancer/HSV thymidine kinase promoter into the third exon of Hprt resulted in variable β-galactosidase expression that was both orientation and cell-type dependent (Shaw-White et al., Transgenic Res.; (1):1-13(1993)). Although transgenes under the control of the human and the chicken β-actin gene promoter resulted in widespread expression when inserted into the Hprt locus, the level of transcripts varied strongly in different tissues (Bronson et al., Proc. Natl. Acad. Sci. USA, 93(17:9067-72 (1996)). Unexpectedly, expression of these transgenes, but not of the endogenous Hprt gene appeared to be low or undetectable in kidney and liver (Bronson et al., Proc. Natl. Acad. Sci. USA, 93(17:9067-72 (1996)). Hatada et al. demonstrated that the HPRT locus suppresses the activity of both, the haptoglobin gene promoter as well as the herpes simplex thymidine kinase promoter in several tissues of mice (Hatada et al., J. Biol., Chem., 274(2):948-55 (1999)). Likewise, a human eNOS promoter-LacZ reporter gene placed in the Hprt locus was found to be inactive in hepatic vessels that otherwise express the endogenous eNOS gene (Guillot et al., Physiol. Genomics, March 13, (2):77-83 (2000). Finally, since the HPRT gene is on the X chromosome, transgene expression at this locus is subjected to random X-inactivation. The expression of the transgene in all cells of the female, therefore, requires the generation of homozygotes.
[0004] To avoid the complications referred to above, it would be desirable to define an autosomal locus that allows strong and predictable expression of transgenes inserted through homologous recombination. It is, however, not predictable for a person skilled in the art whether chromosomal loci which fulfill these criteria are available at all. Exogenous transgenes may not harbor all of the sequences necessary and sufficient for proper regulation of transcription and may therefore be influenced by cis-regulatory elements near the site of insertion.
[0005] The rosa26 locus had been identified by random insertion of retroviral sequences and a β-galactosidase-neomycin resistance fusion gene into the genome of mouse embryonic stem cells (Zambrowicz et al., Proc. Natl. Acad. Sci. USA, 94, 3789-94 (1997)). The rosa26 promoter appeared to mediate ubiquitous expression of promoter-less genes both in embryos and adult mice (Kisseberth et al., Dev. Biol., 214:128-138 (1999); Zambrowicz et al., Proc. Natl. Acad. Sci. USA, 94, 3789-94 (1997)), albeit at different levels in different organs (Vooijs et al., EMBO reports, 21:292-297 (2001)).
[0006] Moreover, WO 99/53017 describes a process for making transgenic animals which ubiquitously express a heterlogous gene, wherein the heterologous gene is under the control of a ubiquitously expressed endogenous promoter, e.g. that of the mouse Rosa26 locus. R. Dacquin et al., Dev. Dynamics 224:245-251 (2002) and K. A. Moses et al., Genesis 31:176-180 (2001) utilize the transgenic mouse strain R26R obtained according to WO 99/53017 for the expression of heterlogous genes. WO 02/098217 describes a method of targeting promoter-less selection cassettes into transcriptionally active loci, such as the Rosa26 locus.
[0007] However, a systematic comparison with other ubiquitous promoters to determine the strength of the Rosa26 promoter had not been performed. In addition, the activity of exogenous promoters inserted into the rosa26 locus has never been examined.
[0008] Finally, WO 03/020743 (published Mar. 13, 2003) describes the expression of transgenes in vivo by targeting protected transgene cassettes into predetermined loci (e.g. the Rosa26 locus), such that the introduced tissue specific exogenous promoter has at least some tissue specific activity. The protected transgene cassette contains (from 5′ to 3′ direction) a transcriptional stop signal, the exogenous tissue specific promoter and the gene of interest. The presence of a transcriptional stop signal is vital for the method of WO 03/020743 as therewith the expression pattern is determined primarily by the nature of the tissue specific exogenous promoter.
SUMMARY OF THE INVENTION
[0009] The present invention is based on the finding that a particular chromosomal locus present within the eukaryotic genome (including that of mammalian ES cells), namely Rosa26, supports the preservation of the inherent activity of heterologous promoters inserted through homologous recombination at that locus. This chromosomal locus is therefore useful in the context of the “targeted transgenesis” approach for the efficient generation of transgenic organisms (such as mice) with a predictable transgene expression pattern.
[0010] Such a “targeted transgenesis” method comprises consecutive experimental steps. A gene expression cassette comprising a suitable promoter (e.g. a ubiquitous or tissue specific promoter, either inducible or constitutive) functionally linked to a gene of interest has to be created; subsequently a vector for the targeted insertion of the above mentioned gene expression cassette into the Rosa26 locus has to be generated; the insertion of the above mentioned gene expression cassette into the Rosa26 locus through homologous recombination or site specific recombination in embryonic stem cells follows; finally transgenic mice are generated by the injection of such genetically modified ES cells into blastocysts.
[0011] More specifically present invention provides
[0012] (1) a method for generating eukaryotic cells having a modified Rosa26 locus, which method comprises the following step (hereinafter shortly referred to as step (a)): introducing a functional DNA sequence into the Rosa26 locus of starting eukaryotic cells, preferably said functional DNA sequence is introduced into the eukaryotic cells by homologous recombination with a targeting vector comprising said functional DNA sequence flanked by DNA sequences homologous to the Rosa26 locus, or by site specific recombinase mediated recombination with a recombination vector comprising said functional DNA sequence flanked by a pair of first recombinase recognition sites (RRSs);
[0000] (2) the method of (1) above, wherein said functional DNA sequence is a gene expression cassette (a) comprising a gene of interest operatively linked to a promoter, or (b) is a DNA sequence which can be converted into such gene expression cassette;
[0000] (3) the method of (1) or (2) above, wherein the eukaryotic cells are mammalian embryonic stem (ES) cells, preferably are non-human mammalian ES cells;
[0000] (4) a targeting vector as defined in (1) or (3) above;
[0000] (5) eukaryotic cells having a modified Rosa26 locus obtainable by the method of (1) and (2) above;
[0000] (6) a method for preparing a transgenenic multi-cell organism having a modified Rosa26 locus which comprises utilizing the method as defined in (1) and (3) above;
[0000] (7) the method of (6) above, wherein the transgenenic multi-cell organism is a non-human mammal and said method comprises modifying an ES cell as defined in (3) above;
[0000] (8) a transgenic multi-cell organism and non-human mammal obtainable by the above defined methods (6) and (7), respectively; and
[0000] (9) the use of the eukaryotic cell of (5) above, the transgenic multi-cell organism of (8) above, or the transgenic non-human mammal of (8) above for gene function studies, drug development, as disease model, etc.
[0013] The method of the invention offers several advantages over the current technology of pronuclear injection. In particular, the targeting vector allows insertion of a single copy of a gene expression cassette, thus avoiding modulation of transgene expression by the arrangement of multiple copies. By choosing the autosomal Rosa26 locus as insertion site, the expression pattern of the inserted transgene in the non-human animal is predictable; random X-inactivation, and/or modulation by chromosomal position effects are avoided. This also eliminates the need to generate and analyse multiple transgenic strains for any given transgene. Finally, the Rosa26 targeting vector for the site-specific integration can be used for multiple gene expression cassettes.
DESCRIPTION OF THE FIGURES
[0014] FIG. 1 : Targeted insertion of CreER and CAGGS-Cre-ER into the Rosa26 locus. A cassette comprising a Cre-ER operationally linked to a CAGGS promoter or a cassette comprising a splice acceptor site (SA) linked to a Cre-ER are inserted into the Rosa26 locus via homologous recombination. A perpendicular dash marks the insertion point within the Rosa26 locus and the rectangular boxes delinate the starting and end points of the Rosa26 transcript.
[0015] FIG. 2 : Southern Blot analysis of the inducible recombination of the Rosa (reporter). (A) Genomic DNA was isolated from liver (Li) spleen (Sp) and small intestine (Si) of transgenic mice carrying the SA-creER/Rosa-rep insert or the CAGGS-creER/Rosa-rep insert. To induce the Cre-ER recombinase the mice were treated with Tamoxifen (treated). As a control, a group of mice with the SA-creER/Rosa-rep insert was left untreated (untreated). Presence of the reporter band (floxed) and deletion (deleted) of it upon an induced recombination event are indicated. (B) Transgenic mice carrying at one Rosa26 locus, a loxP flanked DNA polymerase β gene segment (pol βflox ) and at the other a SA-creER/Rosa-rep were treated with Tamoxifen (treated). A control group of mice was left untreated (untreated). Genomic DNA from liver (Li), spleen (Sp), kidney (Ki), heart (He), lung (Lu), thymus (Th), muscle (Mu), small intestine (Si) and brain (Br) was analysed for presence of pol βflox . In a non-recombination event the pol βflox band remained (floxed), in a recombination event deletion occurred (deleted). (C) As (B), but mice carried instead of the SA-creER/Rosa-rep the CAGGS-creER/Rosa-rep insert.
[0016] FIG. 3 : Western Blot analysis of recombinase and α-actin expression. Proteins were extracted from rosa (SA-CreER T2 ), and rosa (CAGGS-CreER T2 ) mice and analyzed as described in the “Materials and Method” section. The positions of bands representing CreER T2 and actin are indicated. FA: fat tissue, Ty: Thymus; Sp: spleen, Br: Brain, Lu: lung, He: heart.
[0017] FIG. 4 : Fabp-Cre targeting vector. An expression cassette, in which the Cre recombinase is expressed under the control of the Fabpl 4× at −132 promoter is inserted into the Rosa26 targeting vector. This vector was used to insert the Fabp-Cre cassette into the Rosa26 locus by homologous recombination in ES cells.
[0018] FIG. 5 : ROSA26 locus of the Cre reporter mice carrying a Cre substrate reporter construct. A recombination substrate (Seq ID NO: 9) has been inserted in the ROSA26 locus. The substrate consists of a CAGGS promoter followed by a cassette consisting of the hygromycin resistance gene driven by a PGK promoter and flanked by loxP recombination sites. This cassette is followed by the coding region for beta-galactosidase, which is only expressed when the hygromycin resistance gene has been deleted by recombination.
[0019] FIG. 6 : In situ detection of beta-galactosidase in cryosections of different tissues of Fabp-Cre/reporter substrate double transgenic mice. Mouse tissues were embedded in OCT, frozen and cut into microsections. The sections were stained for beta-galactosidase activity (indicated by the blue color) by X-gal staining, counterstained with Nuclear Fast Red Solution, dehydrated, mounted and photographed.
DETAILED DESCRIPTION OF THE INVENTION
[0020] The term “living organisms” according to the present invention relates to multi-cell organisms which can be vertebrates such as mammals (e.g. non-human animals such as rodents including mice and rats; and humans) or non-mammals (e.g. fish) or can be invertebrates such as insects or worms, or can be plants (higher plants, algi or fungi). Most preferred living organisms are mice and fish.
[0021] “Eukaryotic cells” and “starting eukaryotic cells” according to the present invention include cells isolated (derived) from the above defined living organisms and cultured in vitro. These cells can be transformed (immortalized) or untransformed (directly derived from living organisms; primary cell culture). The term “eukaryotic cells” also includes mono-cellular eukaryotic cells such as yeasts, etc.
[0022] It is preferred in the method (1) of the present invention that the eukaryotic cells are derived from a multi-cell organism including vertebrates, invertebrates and plants, preferably is a vertebrate cell, more preferably is derived from a mammal, including rodents such as mouse, rat, etc., or a fish such as zebrafish.
[0023] In the method (1) of the invention it is preferred that the functional DNA sequence comprises a gene encoding a protein/peptide of interest (i.e. is a expressible and translatable DNA sequence), more preferably said functional DNA sequence is a gene expression cassette (a) comprising a gene of interest operatively linked to a promoter, or (b) is a DNA sequence which can be converted into such gene expression cassette (i.e. into an operatively linked “promoter-gene of interest” construct, e.g. by subsequent modification reactions after its integration). The gene of interest within the gene expression cassette can be any gene coding for a certain protein/peptide of interest, including, but not limited to, recombinases, reporter genes, receptors, signaling molecules, transcription factors, pharmaceutically active proteins and peptides, drug target candidates, disease causing gene products, toxins, etc.
[0024] The promoter of the gene expression cassette (which is a heterologous promoter relative to the Rosa26 locus) preferably is a ubiquitous or tissue specific promoter, either constitutive or inducible. The ubiquitous promoter in the vector according to the invention is preferably selected from polymerases I, II and III dependent promoters, preferably is a polymerase II or III dependent promoter including, but not limited to, a CMV promoter, a CAGGS promoter, a snRNA promoter such as U6, a RNAse P RNA promoter such as H1, a tRNA promoter, a 7SL RNA promoter, a 5 S rRNA promoter, etc. Particularly preferred ubiquitous promoters are CAGGS, hCMV, PGK. Preferred tissue specific promoters are FABP (Saam & Gordon, J. Biol. Chem., 274:38071-38082 (1999)), Lck (Orban et al., Proc. Natl. Acad. Sci. USA, 89:6861-5 (1992)), CamKII (Tsien et al., Cell 87: 1317-1326 (1996)), CD19 (Rickert et al., Nucleic Acids Res. 25:1317-1318 (1997)); Keratin (Li et al., Development, 128:675-88 (201)), Albumin (Postic & Magnuson, Genesis, 26:149-150 (2000)), aP2(Barlow et al., Nucleic Acids Res., 25 (1997)), Insulin (Ray et al., Int. J. Pancreatol. 25:157-63 (1999)), MCK (Brüning et al., Molecular Cell 2:559-569 (1998)), MyHC (Agak et al., J. Clin. Invest., 100:169-179 (1997), WAP (Utomo et al., Nat. Biotechnol. 17:1091-1096 (1999)), Col2A (Ovchinnikov et al., Genesis, 26:145-146 (2000)); preferred inducible promoter systes are Mx (Kühn et al. Scinence, 269: 1427-1429 (1995)), tet (Urlinger et al., Proc. Natl. Acad. Sci. USA, 97:7963-8 (2000)), Trex (Feng and Erikson, Human Gene Therapy, 10:419-27). Suitable inducible promoters are the above-mentioned promoters containing an operator sequence including, but not limited to, tet, Gal4, lac, etc.
[0025] The targeting vector, recombination vector, functional DNA sequence or gene expression cassette may further comprises one ore more additional functional sequences including but not limited to (selectable) marker genes (such as the neomycin phosphotransferase gene of E. coli transposon, etc.), recombinase recognition sites (which in case of the recombination vector differ from the first recombinase recognition sites and which include loxP, FRT, variants thereof, etc.), poly A signals (such as synthetic polyadenylation sites, or the polyadenylation site of human growth hormones, etc.), splice acceptor sequences (such as a splice acceptor of adenovirus, etc.), introns, tags for protein detection, enhancers, selection markers, etc.
[0026] In a preferred embodiment methods (1) to (3) of the invention comprise homologous recombination. It is then preferred that the DNA sequences homologous to the Rosa26 locus are 0.2 to 20 kB, preferably 1 to 10 kB long. In a particularly preferred embodiment of the method (2) the eukaryotic cells are derived from mouse, the DNA sequences homologous to the Rosa26 locus are derived from the 5′ and 3′, flanking, arm of the mouse Rosa26 locus, preferably said homologous DNA sequences having the sequences shown in SEQ ID NO:4 and 5, respectively, and the promoter is a CAGGS-promoter, most preferably the targeting vector has the sequence shown in SEQ ID NO:7.
[0027] In a further preferred embodiment, methods (1) to (3) of the invention comprise recombinase mediated recombination. The insertion of transgenes or DNA segments into the genome can be mediated by site specific recombination (Fukushige & Sauer, Proc. Natl. Acad. Sci. USA 89(17):7905-9 (1992)). A site specific recombinase like cre or FLP recombines two recognition target sites like loxP or FRT, respectively. The use of two incompatible recognition target sites (F3 or F5, Schlake & Bode, Biochemistry, 1994 Nov. 1, 33(43):12746-51) or inverted recognition target sites (Feng et al., J. Mol. Biol. 292(4):779-85 (1999)) allows the insertion of DNA segments flanked by two incompatible or inverted target sites. This exchange system has been called recombinase mediated cassette exchange (RMCE). In a preferred embodiment a FLP based RMCE system is inserted into the Rosa26 locus. Said recombinase mediated recombination preferably comprises the steps:
(a1) introducing into the starting cells an acceptor DNA which integrates into the genome of the starting cell, the acceptor DNA comprising two mutally incompatible first RRSs, and introducing into the therewith obtained cell (a2) a donor DNA comprising the same two mutually incompatible first RRSs contained in the acceptor DNA by utilizing a recombination vector as defined above; and (a3) the recombinase which catalyzes recombination between the RRSs of the acceptor and donor.
[0031] In said recombinase mediated recombination method it is preferred that
(i) the RRS are loxP or FRT sites or variants thereof (such as single mutant recognition sited lox66 and lox71 (Albert et al., The Plant J. 7:649-659 (1995)); and/or (ii) the acceptor DNA comprises a negative selectable marker (e.g. herpes simplex virus thymidin kinase gene, etc.) and or (iii) the donor DNA comprises an inactive positive selection marker (e.g. neomycin phosphotransferase, etc.).
[0035] For further selectable markers it is referred to U.S. Pat. Nos. 5,487,932 and 5,464,763 which are hereby incorporated in their entirety.
[0036] In a particularly preferred embodiment of the methods (1) to (3), and in particular if the method comprises homologous recombination, the expression cassette
(i) is free of a transcriptional stop signal 5′ to the (heterologous) promoter of the cassette (i.e. is a non-protected cassette); and/or (ii) the exogenous promoter is a ubiquitous (constitutive or inducible) promoter.
[0039] The methods (1) to (3) may further (besides step (a) defined above) comprise one or more of the steps (b) isolating the eukaryotic cells, preferably the ES cells having the desired fuctional DNA sequence integrated into the Rosa26 locus; and/or (c) modifying the integrated functional DNA sequence and isolating (ES) cells having the desired modified functional DNA sequence.
[0040] The steps (a) and (b) of the methods (1) to (3) are preferably performed in vitro. The step (c) may be performed in vitro and in vivo.
[0041] The invention also provides a method for preparing a transgenenic multi-cell organism having a modified Rosa26 locus which comprises utilizing the method as defined in (1) to (3) above. This includes a method for preparing a non-human mammal comprising modifying starting ES cells according to steps (a) to (c). The ES cells may subsequently processed according one or more of the following steps:
[0000] (d) the ES cells obtained in steps (b) or (c) are injected into blastocysts; and or
[0000] (e) transgenic non-human animals carrying one or more functional genes of interest at the Rosa26 locus are generated (viz, by well known breeding procedures).
[0042] The transgenic multi-cell organisms and non-human mammals obtainable by the method (6) and (7), respectively; preferably have an operatively functional gene expression cassette (as defined above) integrated into its Rosa26 locus. Such transgenic multi-cell organisms and non-human mammals are suitable for gene function studies, drug development, as disease model animals, etc.
[0043] The invention is further explained by the following examples and the attached figures, which are, however not to be construed so as to limit the invention.
EXAMPLES
[0000] Materials and Methods
[0000] Plasmid Construction:
[0044] 1. CreER Rosa-targeting vector: A 129 SV/EV-BAC library (Incyte Genomics) was screened with a probe against exon2 of the Rosa26 locus (amplified from mouse genomic DNA using Rscreen1s (GACAGGACAGTGCTTGTTTAAGG) (SEQ ID NO:1) and Rscreen1as (TGACTACACAATATTGCTCGCAC) (SEQ ID NO:2)). Out of the identified BACclone a 11 kb EcoRV subfragment was inserted into the HindII site of pBS. Two fragments (a 1 kb SacII/XbaI- and a 4 kb XbaI-fragment) were used as homology arms and inserted into a vector containing a FRT-flanked neomycin resistance gene (unpublished) to generate the basic Rosa26 targeting vector. The CAGGS-promoter (SEQ ID NO:6, nucleotides 1-1616) or a splice acceptor site (SA) from adenovirus (Friedrich G., Soriano P., Genes Dev., 5:1513-23 (1991)) were inserted between the 5′ arm and the FRT flanked neomycin resistance gene. The CreER T2 and a polyadenylation site (pA; SEQ ID NO: 6, nucleotides 3921-4099) were cloned 3′ of the SA or the CAGGS-promoter. The vector is free of a transcriptional stop sequence 5′ to the CAGGS-promoter
[0045] 2. FABP-Cre Rosa-targeting vector (SEQ ID NO:8): The splice accetpr site from adenovirus (SEQ ID NO:8, nucleotides 18569-18689) was inserted into the basic Rosa26 targeting vector described in 1, above. Into the SwaI and AscI restriction sites of the resulting plasmid was inserted a 3195 bp Xba blunt /AscI DNA fragment comprising in 5′ to 3′ order the polyadenylation signal from the human growth hormone gene (SEQ ID NO:8; nucleotides 18760-688; Bond et al, Science 289:1942-1946 (2000)), a modified Fabpl promoter (SEQ ID NO:8, nucleotides 702-1481; Fabpl 4× at −132 ; Simon et al., J. Biol. Chem. 272:10652-10663 (1997)), a synthetic intron (SEQ ID NO:8, nucleotides 1521-1758), the Cre coding sequence (SEQ ID NO:8, nucleotides 1778-2830) and a synthetic polyA signal (SEQ ID NO: 8, nucleotides 2888-3066).
[0046] Cell culture: Culture a and targeted mutagenesis of ES cells were carried out as previously described (Hogan et al., (Cold Spring Harbor Laboratory Press, Cold Spring Harbor N.Y.), pp. 253-289.) with ES cell lines derived from both inbred and F1 embryos.
[0047] Mice: All mice were kept in the animal facility at Artemis Pharmaceuticals GmbH in microisolator cages (Tecniplast Sealsave). B6D2F1 Mice for the generation of tetraploid blastocysts were obtained from Janvier. The polb flox /rosa(CreER T2 ) and ect2 flox /rosa(CreER T2 ) mice were generated by breeding of rosa(CreER T2 ) ES mice with βT14 (Gu et al., Science, 265, 103-106.), respectively.
[0048] Production of ES mice by tetraploid embryo complementation: The production of mice by tetraploid embryo complementation was essentially performed as described (Eggan et al., Proc Natl Acad Sci USA, 98, 6209-6214.).
[0049] Ligand administration: 100 mg Tamoxifen-free base (Sigma, T5648) was suspended in 100 μl Ethanol and solved in 1 ml sunflower oil (Sigma). This 10 mg/100 μl tamoxifen solution was, sonicated for 1-2 minutes and then stored at −20° C. For p.o. administration the solution was thawed at 55° C. and administrated to 4-8 week old mice by a feeding needle (FST Fine Science Tools GmbH, 18061-20).
[0050] Western blot analysis: Western blot analysis was performed using SDS-PAGE (NuPAGE, Invitrogen) and the Breeze Immunodetection System (Invitrogen) according to the manufacturer protocols. Immunodetection was done using sc-543 (HC-20, Santa Cruz Biotechnology, Inc.) against ER, PRB-106C against cre, actin sc-1616 Actin (I-19) against actin and rabbit polyclonal IgG (Santa Cruz Biotechnology, Inc.) antibodies.
[0051] X-Gal staining on tissue sections: To detect beta-galactosidase activity, tissues were embedded in Tissue Tec OCT (Sakura Finetek Europe B. V., The Netherlands), frozen on dry ice and cut into microsections. The sections were mounted onto slides and dried for 1-4 hours at room temperature. Sections were fixed for 5 min at room temperature in fixing solution (0,2% glutaraldehyde, 5 mM EGTA, 2 mM MgCl 2 in 0.1 M PB ((0.1 M K 2 HPO 4 , pH 7.3)) and washed three times for 15 min at room temperature in washing buffer (2 mM MgCl 2 , 0.02% Nonidet-40 in 0.1 M PB). Subsequently, tissues were stained for beta-galactosidase activity over night at 37° C. using X-Gal solution (0.6 mg/ml X-Gal (predissolved in DMSO), 5 mM potassium hexacyanoferrat III, 5 mM potassium hexacyanoferrat II, in washing buffer). Sections were washed twice for 5 min at room temperature in PBS, counterstained with Nuclear Fast Red Solution for 10 min, rinsed shortly in aqua dest., dehydrated through a graded ethanol series and mounted in Eukitt (Sigma, Germany).
Example 1
[0052] A CreER T2 gene (Feil et al., (1997) Biochem Biophys Res Commun., 237, 752-757) under the control of the CAGGS-promoter (Okabe, Fabs Letters 407:313-19 (1997)) was inserted into the rosa26 locus by homologous recombination in ES cells by utilizing the CreER Rosa-targeting vector as described above ( FIG. 1 ). In addition to the CreER T2 gene a splice acceptor sequence (Friedrich and Soziano (1991), Genes Dev., 9, 1513-1523) was introduced as a control for the endogenous activity of the rosa26 gene promoter ( FIG. 1 ). A loxP-flanked hygromycin resistance gene was introduced into the second allele of rosa26 to provide test substrate for Cre ER T2 (Seibler et al., Nucl. Acids. Res. Feb. 15, 2003, 31(4):(12) (2003)), in press). ES cells modified at both rosa26 alleles were injected into tetraploid blastocysts and completely ES cell derived mice were generated (Eggan et al., (2001). PNAS, 98, 6209-6214). Rosa(SA-CreER T2 /reporter) and Rosa(CAGGS-CreER T2 /reporter) mice were fed with daily 5 mg Tamoxifen for 5 days and recombination of the reporter was analyzed 3 days after the last administration. Southern analysis of genomic DNA from different organs showed up to 50% recombination in the Rosa(SA-CreER T2 /reporter) mice and up to 90% recombination in the rosa(CAGGS-CreER T2 /reporter) mice, respectively ( FIG. 2A ). As the second substrate, we used the loxP flanked DNA polymerase β gene segment (polβ flox ) (Gu et al., (1994). Science, 265, 103-106). The polβ flox /rosa(SA-CreER T2 ) and polβ flox /rosa(CAGGS-CreER T2 mice were fed with 5 mg tamoxifen per day for 5 days and analyzed 3 days later. Southern blot analysis revealed that the loxP-flanked polymerase β gene segment was excised in more than 90% of cells in all organs except brain in the rosa(SA-CreER T2 /reporter) mice ( FIG. 2B ). In contrast, the degree of inducible recombination was significantly higher in rosa(CAGGS-CreER T2 /reporter) mice, reaching 100% efficiency in most organs and up to 70% in brain.
[0053] To investigate the pattern and level of CreER T2 expression in rosa(SA-CreER T2 ) and rosa(CAGGS-CreER T2 ) mice, we performed Western analysis using antibodies specific for Cre. The 74 kDa band corresponding to the CreER T2 fusion protein was detectable in all organs of rosa(CAGGS-CreER T2 ) mice, including brain ( FIG. 3 ). In contrast, the CreER T2 expression level in rosa(SA-CreER T2 ) mice was significantly lower compared to the rosa(CAGGS-CreER T2 ) strain and appeared to be undetectable in brain ( FIG. 3 ).
Example 2
[0054] A Cre gene under the control of the Fabpl 4× at −132 -promoter (SEQ ID NO:8; FIG. 4 ) was inserted into the Rosa26 locus by homologous recombination in F1 ES cells carrying a Cre reporter substrate in the second Rosa26 allele. LacZ expression from the reporter construct (SEQ ID NO:9; FIG. 5 ) is activated upon Cre-mediated recombination. Targeted ES cells were injected into tetraploid blastocysts to generate FABP-Cre/reporter-substrate double transgenic ES mice. The Cre recombination pattern in these mice was examined by analyzing beta-galactosidase activity in tissues sections ( FIG. 6 ). Cre-mediated recombination in these mice was restricted to the intestinal epithelium, liver and part of the cells in the epithelium of the tubuli in the kidney, thus exactly reflecting the expression pattern of the endogenous Fabpl gene (Simon et al., J. Biol. Chem., 272:10652-10663 (1997)).
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The invention provides a method for targeted transgenesis using the Rosa26 locus. Suitable nucleotide acid sequences and vectors for the targeted transgenesis and recombinase mediated transgenesis are provided. The Rosa26 locus proved to be a suitable integration site allowing strong and predictable expression of inserted transgenes carrying exogenous promoters.
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PRIORITY AND INCORPORATION BY REFERENCE
[0001] This application claims the benefit of Prov. Pat. App. No. 62/101,982 filed Jan. 9, 2015 which is incorporated herein in its entirety and for all purposes. This application incorporates by reference, in their entireties and for all purposes, U.S. Pat. No. 6,570,584 filed May 15, 2000, U.S. Pat. No. 7,519,603 filed Nov. 27, 2002, U.S. Pat. No. 6,320,112 filed May 18, 2001, U.S. Pat. No. 6,353,170 filed Sep. 3, 1999 and U.S. Pat. App. Nos. 20080055479 A1 filed Sep. 4, 2007 and 20060285136 filed Mar. 13, 2006.
BACKGROUND OF THE INVENTION
[0002] The tasks of composing and editing musical compositions have long been tedious work characterized by use of modern staff notation. Generations of composers and musicians have learned this method of composing, memorializing, and/or playing various works. However, many fail to attempt or master the rigors of reading and writing in modern staff notation. For example, The Beatles, Jimi Hendrix, and Eric Clapton became famous, although they were arguably “illiterate” musicians because they could not read music. The music of many less famous musicians has likely been lost for lack of the ability to record it in traditional modern staff notation. A solution to this problem is to replace modern staff notation with a more accessible technique for composing and memorializing musical works.
FIELD OF INVENTION
[0003] This invention relates to machines, articles of manufacture, and processes. In particular, a computer based aid for composing, editing, and playing music is provided.
DISCUSSION OF THE RELATED ART
[0004] The scholar and music theorist Isidore of Seville, writing in the early 7th century, considered that “unless sounds are held by the memory of man, they perish, because they cannot be written down.” Since music's Classical period, from about 1750 to 1820, music notation including a multi-line or five-line staff has been known and adapted in what has been called a system of “modern” music notation. Known and used by Chopin and Taylor Swift alike, the term “modern” appears misplaced as there has been only little improvement during the last two centuries. In particular, this ancient system of music notation has been an impediment to both those who would compose new music and those learning to play music presented in this format.
SUMMARY OF THE INVENTION
[0005] Embodiments of the present invention provide one or more aids for composing, editing and playing musical works.
[0006] In an embodiment, a music composition, editing, and playback system comprises: a processor and one or more input/output devices including a display or displays which may include a touch sensitive display screen; the processor for executing a computer readable code for music composition, editing, and playback; musical notes and chords are visualized in one or more note circles, each note circle including an octave of notes; each chord visualization derived from one or more of seven base vector triads, has a particular polygonal shape colored with a particular hue, differs from visualizations of other chords for at least one of a different shape or a different hue, and includes an indication of the chord root note; visualizations of musical rhythms created by aggregation of plural ones of the visualized notes and chords in a time circle; time circle circumference equal to a particular musical distance and a time marker for moving around the circle; and, the aggregation of notes and chords visualized in the time circle in accordance with a user selected rate or scale of the time marker.
[0007] Embodiments of the invention provide a computing, internet, and/or cloud based platform for musical expression, collaboration, creativity & content sharing, with a user interface design based on a geometric interpretation of music theory.
[0008] In an embodiment, the user interface design for music shaper translates western music theory into a notation of shape and color, allowing the user to easily and intuitively express themselves through touch interactions.
[0009] In an embodiment, the invention is an enabler for writing music without detailed knowledge of music notation. This enabler avoids the music notation of the present centuries old system which delays learning by, among other things, obfuscating the mathematical structures present in music. This representation removes obfuscations, and enables user interfaces for intuitive operation.
[0010] Music Shaper can benefit society because it will help more people experience and write music in a new and fun way. It will share concepts from upper division and graduate mathematics, graphically, with the general public. By helping people through the learning curve for music writing, it opens up commercial potential for new economic interactions allowing users to sell each other content they create.
[0011] Music Shaper can impact society by helping transform the internet from a market of advertisers to a more desirable market of content producers, and simultaneously advance the state of the art in distributed computing.
[0012] Goals of the Music Shaper include one or more of constructing a software system that allows untrained musicians, to compose and play complete works of music, using intuitive 2D and 3D visual, touch, and gesture based interfaces. These interfaces are designed using a geometric and higher dimensional interpretation of the syntax and semantics of music theory. Embodiments enable the user to sculpt music out of geometric shapes with their fingertips, the product being a work that is consistent with the rules of Western music theory, but not unnecessarily limited in content, structure, or genre.
[0013] In an embodiment the invention provides a method of representing a complete chord catalog, the method comprising the steps of: constructing a parameterized curve encircling an axis multiple times; representing “n” musical octaves with the curve such that for any integral number of octaves the curve origin and end lie in the same plane as the axis; positioning notes on the curve to form a 12 tone equal temperament tuning system for each octave; taking 3 notes at a time selecting the 7 largest triangles that interconnect 3 notes wherein each newly selected triangle is neither of an inversion of or a rotationally symmetric copy of any one of the previously selected triangles [and] wherein each of the selected triangles represents a musical chord; and, from the 7 chords, selecting a set of chords that forms a four layer decision tree; wherein each chord in the set of chords is a composite (more than 3 notes) of 2 to 4 of the 7 chords, the set of chords includes every unique composite chord, and in three adjacent layers successive chords are selected such that the latter chord shares a vertex with the prior chord.
[0014] In another embodiment the invention provides a method of creating colorations for three note chords, the method comprising the steps of: selecting a first set of CIECAM02 environmental parameters including adaptation, surrounding lighting, background luminance, and white point; after the environmental parameters are selected, selecting a second set of CIECAM02 parameters including lightness and chroma; displaying a CIECAM02 hue wheel parameterized by lightness and chroma; in a default interval color selection, locating six substantially equally spaced roundels on the hue wheel, each roundel identifying a different interval color; providing a roundel or hue wheel adjustor enabling a user to relocate the roundels on the hue wheel for adjusting interval colors; selecting sets of interval colors for mixing to produce chord coloration for symmetric chord pairs, asymmetric chords, and corresponding colors for chord inversions; verifying that the chord colors when mapped from a CIELUV color space to a CIECAM02 color space are in gamut; for “n” octaves defining (n×12) notes, setting a first lightness for the lowest frequency note and a second lightness for the highest frequency note, the intermediate notes being spaced by equal frequency increments; for each represented note, determining a chroma value that assures the note is displayable for all hues; varying hue to represent different inversions of a chord; varying lightness to indicate note frequency; and, from the collection of three note chords inherent in the “n” octaves, selecting and displaying an image of the chord that is colored in accordance with the above steps.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The present invention is described with reference to the accompanying figures. These figures, incorporated herein and forming part of the specification, illustrate embodiments of the present invention and, together with the description, further serve to explain the principles of the invention and to enable a person skilled in the relevant art to make and use the invention.
[0016] FIG. 1 shows a drawing of an interval lotus of the present invention.
[0017] FIG. 2 shows a drawing of chord construction of the present invention.
[0018] FIG. 3 shows a drawing of multiple triad chords within a note circle of the present invention.
[0019] FIG. 4 shows a drawing of a triad chord and lotus reaches emanating from triad vertices of the present invention.
[0020] FIGS. 5A-B show a symmetric lotus and corresponding plume tabulation of the present invention.
[0021] FIGS. 6A-F and FIG. 7 show construction of a starburst of the present invention.
[0022] FIGS. 8A-C show interval formation from intersecting starbursts of the present invention.
[0023] FIGS. 9A-C show formation of triad and composite chords of the present invention.
[0024] FIGS. 10A-C show harmony spirals of the present invention.
[0025] FIG. 11 and FIGS. 12A-B show note grids of the present invention.
[0026] FIG. 12C shows exemplary transformations provided by the present invention.
[0027] FIGS. 13A-H show a rhythm system of the present invention.
[0028] FIG. 14 shows a loop selector of the present invention.
[0029] FIG. 15A-D show a graph of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0030] The disclosure provided in the following pages, including Attachment I, describes examples of some embodiments of the invention. The designs, figures, and descriptions are non-limiting examples of certain embodiments of the invention. For example, other embodiments of the disclosed device may or may not include the features described herein. Moreover, disclosed advantages and benefits may apply to only certain embodiments of the invention and should not be used to limit the disclosed inventions.
[0031] FIG. 1 shows an interval lotus 100 . Arranged with a circle 102 , the lotus shows twelve notes (see e.g., 104 note C) of an octave evenly spaced around the circle. Inside the circle are reaches of the lotus along paths between a root note, here D#, and each of the other notes around the circle.
[0032] The reaches appear as plumes with varying different hues. As seen, the plumes to either side of a central plume from D# to A ( 116 ) colored in pinkish purple appear as mirror images in both form and hue. As shown, the D# to E ( 106 ), D is colored in olive green, D# to F ( 108 ), C# is colored in blue, D# to F# ( 110 ), C is colored in blue purple, D# to G ( 112 ), B is colored in orange, D# to G# ( 114 ), A# is colored in lime green. These colors may be referred to herein in accordance with the hue table below.
[0000]
Hue Table
Hue
Designation
Dark green or olive green
G1
Blue
B
Purple or blue purple
P
Orange
O
Light green or lime green
G2
Pinkish purple
F
[0033] The interval lotus may be used in connection with formulating and/or describing, among other things, musical notes, diads, and triads. For example, the interval lotus aids selection of key and chords using a circular context.
[0034] FIG. 2 shows how a particular musical chord, a three note triad, is fitted into a note circle 200 . At right in the FIG. 210 are four basic triads, major, minor, diminished, augmented and three additional triads 7 No 5, Mb5, and Sus 2. The triads characterize chord quality and are represented by polygons of different colors or hues. Further, the major and minor chords are structural mirror images as are the 7 No 5 and Mb5 chords. Any one of these triads may be fitted into the interval lotus space and aligned to provide a particular root note. At left in the FIG. 211 , a minor chord 204 is shown fitted into the interval lotus space. A delta or chevron 206 imposed on the chord points to E, the chord root note 208 . As seen, different or additional triad chords 202 , 204 may also be fitted into the interval lotus space.
[0035] FIG. 3 shows a four triad chords in a note circle 300 . As shown, a Sus 2 triad 302 has root note D, a major triad 304 has a root noted F, a diminished chord 306 has a root note F#, and a fourth triad 308 has a root note A.
[0036] FIG. 4 shows a single triad chord in an interval lotus including lotus reaches emanating from chord vertices 400 . In particular, the chord shown is an augmented chord 408 with vertices 402 , 404 , 406 at respective notes C#, A, and F. Starbursts at the chord vertices are discussed below.
[0037] Chords may be derived from seven (7) base vector triads and may be represented by selected corresponding colors and shapes such as polygons and these may be used to construct individual chords. Alternately a library of chords or keys and chords may be navigated by decision tree, by geometric configuration, and also by chord name. Intervals are represented by the coloration of a lotus, and the interaction of the lotus can be used to show individual interval influences for note choices and the structure of chord support for a given configuration of notes. Embodiments of the present invention enable visualization of these choices. These choices can be visualized in real time for played notes such as midi notes. A library of keys can also be implemented by chord choice in tree format. As is further explained below, embodiments of the present invention may provide a chord navigator allowing for rotation and basic transformations of key objects, along with root/mode setting, and quick play of modes for musical feeling ear training.
[0038] In an embodiment, a chord selection application allows the user to see the geometric configuration of keys 220 in the note circle, test out notes, and apply composite chords to the note circle 102 . Here, the user may rotate key, set accidental, set mode, apply multiple chords and rotate them through constrained locations. In various embodiments, the twelve (12) notes on the circle are active midi note send regions. Notes not in the key will be prevented from playing, as will notes outside a chord if a chord is selected. The application displays the seven (7) basic triads from which all other notes may be selected. The interface will display the selected key and mode, and will also display the current selected chord components and its root note. In some embodiments the chords will show a delta on the triangle, to indicate their root position, and the system will indicate which mode has been selected by highlighting it. The system may also highlight a point of the key if it has been set with an accidental and the system may allow chords to be locked and unlocked, and also cleared.
[0039] The above provides an introduction to methods of visualization of various musical elements as disclosed herein. These and other methods useful in tasks including composing, editing, and playing musical works are explained in some detail below.
[0040] FIGS. 5A-12B illustrate means for visualizing and/or displaying musical notes, intervals, triad chords, and composite chords.
[0041] Embodiments of the present invention may utilize one or more display architectures to characterize elements of a musical work. Features of a display architecture may include two and/or three dimensional geometric figures and collections of such geometric figures. Additional information about the musical element may be added by marking geometric figures as through the selection of hue, chroma, and lightness values.
[0042] Geometric figures include loti, starbursts, intervals, diads, triads, and groups of one or more of these figures. And, as explained below, loti may be used as building blocks to construct a starburst. From two intersecting starbursts an interval between notes may be determined. Three intervals may be used to determine a triad musical chord and multiple triad chords may be used to determine a composite chord.
[0043] Turning now to the construction of starbursts from loti, FIG. 5A shows a symmetric lotus 500 A indicative of an exemplary octave in a 12 tone equal temperament tuning system. The notes of the octave are indicated by evenly spaced marks 504 located along a lotus circle or octave path 501 . Lotus intervals are indicated by plumes that lie along lines between a lotus root note 506 and another note of the octave 504 . Notably, the plumes may emanate from, but avoid contact 508 with either or both of the root note and the notes to which they lead. For example, a maximum lotus interval may be indicated by a plume 502 centrally located in the lotus and lying along a line between a root note 506 and a note opposite the root note 504 . Given there are 12 notes in the octave, five intervals lie to the left of the central interval and five intervals lie to the right of the central interval.
[0044] FIG. 5B shows a tabular description of lotus plumes 500 B. At the center of the table is a central or zero plume with a hue “F” which may be equated with pinkish purple or fuchsia. To the right and left of center are first plumes 1(right) and 1(left) with hues “G1” that may be equated with a dark green. To the right and left of the first plumes are second plumes 2(right) and 2(left) with hues “0” that may be equated with orange. To the right and left of the second plumes are third plumes 3(right) and 3(left) with hues “P” that may be equated with purple. To the right and left of the third plumes are fourth plumes 4(right) and 4(left) with hues “B” that may be equated with blue. To the right and left of the second plumes are fifth plumes 5(right) and Weft) with hues “G2” that may be equated with a light green.
[0045] The lotus of FIG. 5A is termed a “symmetric lotus” because the plume hues are symmetric about the central plume such that corresponding plume pairs 1(right):1(left), 2(right):2(left), 3(right):3(left), 4(right):−4(left), and 5(right):5(left) have the same hue. In the case of a right asymmetric loti (see e.g., FIG. 6D ), the 2 nd and 3 rd plume hues on the right are reversed and the 4 th and 5 th plume hues on the right are reversed. In the case of a left asymmetric loti (see e.g., FIG. 6F ), the 2 nd and 3 rd plume hues on the left are reversed and the 4 th and 5 th plume hues on the left are reversed.
[0046] Whether a lotus is symmetric or asymmetric, it may be described as having a lotus root or base note and a corresponding root or maximum interval between notes such that the lotus includes a first or lower range of five intervals to one side of the maximum interval and a second or higher range of five intervals to the other side of the maximum interval.
[0047] It should be noted that while a lotus may be used to describe intervals in a single octave as seen above, intervals may also extend between a root note and a note in the same or a different octave as is further explained in connection with harmony spirals below.
[0048] FIGS. 6A-F show illustrate features of an exemplary starburst harmony spiral 600 A-F.
[0049] As shown in FIG. 6A , a starburst harmony spiral 600 A may include a starburst or multi-lotus construct 608 within a harmony or multi-octave spiral 682 . As described below, the starburst may be constructed, in a manner of speaking, by stacking loti in an octave spiral. As shown, there are six plumes 631 - 636 that are the central plumes of six loti and each of the plumes emanates away from a common starburst root note 679 at a starburst midplane 677 .
[0050] FIG. 6B shows a portion of the FIG. 6A multi-octave spiral 600 B. The portion shown 619 includes an octave of 12 notes, the notes being represented by marks 617 that are equally spaced around the spiral.
[0051] FIG. 6C shows the FIG. 6A multi-octave spiral 600 C. In the spiral 682 , six lines or plumes indicate starburst root note intervals, each interval spanning between the common starburst root note 679 and a central note of a respective octave. The starburst root note lies in a starburst midplane 677 that is about perpendicular to a spiral axis x-x. As shown, there are three lower intervals 631 - 633 in three lower octaves and three upper intervals 634 - 636 in three upper octaves.
[0052] Where as here, a common root note 679 is used in connection with each of the intervals 631 - 636 , one note of each octave above and below the starburst root note 679 is unused as it is replaced by the starburst root note. See for example the exemplary unused note 617 in the lowest octave or partial octave of FIG. 6A .
[0053] In the spiral 682 of FIG. 6A , right asymmetric, and left asymmetric loti are formed. These loti are octaves of the spiral that are collapsed to form a planar figure. For example, in FIG. 6D , a right asymmetric lotus characteristic of an upper octave (see e.g. 634 ) 600 D is shown. As indicated by the corresponding tabulation of lotus plumes, intervals to the left of the root interval 635 have hues matching those of a symmetric lotus while intervals to the right of the root interval swap 2nd and 3 rd interval hues and swap 4 th and 5 th interval hues.
[0054] In FIG. 6F , a left asymmetric lotus characteristic of a lower octave 631 - 633 is shown 600 F. As indicated by the corresponding tabulation of lotus plumes, intervals to the right of the root interval 633 have hues matching those of a symmetric lotus while intervals to the left of the root interval swap 2nd and 3 rd interval hues and swap 4 th and 5 th interval hues as compared to the symmetric lotus.
[0055] In FIG. 6E , a symmetric lotus is shown 600 E. This lotus is formed by the starburst root note 679 and the six notes to either side of the starburst root note. Notably, unlike asymmetric loti that fill upper and lower octaves, the symmetric lotus includes the adjoining symmetric portions of the first upper right asymmetric lotus and the first lower left asymmetric lotus. Because the symmetric lotus octave includes notes to either side of the starburst root note, all of the notes in this octave are used. And, because octaves other than the symmetric lotus octave do not include the starburst root note, one note of each such octave is not used.
[0056] FIG. 7 illustrates construction of an exemplary starburst harmony spiral including two octaves 700 .
[0057] At left is a schematic 702 of upper and lower octaves 706 , 708 joined at a common spiral root note 679 at a starburst midplane 677 . The upper octave 706 includes a right asymmetric portion 712 and a left symmetric portion 713 . The lower octave 708 includes a right symmetric portion 723 and a left asymmetric portion 722 . About the midplane 677 the left symmetric octave 713 and the right symmetric octave 723 are joined at the common spiral root note 679 to form a symmetric octave 730 .
[0058] At right is a harmony spiral 704 including the two octaves 706 , 708 joined at the common spiral root note 679 .
[0059] The spiral display of the upper octave 706 may be collapsed to form a right asymmetric lotus with a central plume 734 . The octave asymmetric portion 712 has a note color sequence of B-G2-O-P-G1-F.
[0060] The spiral display of the lower octave 708 may be collapsed to form a left asymmetric lotus with a central plume 733 . The octave asymmetric portion 722 has a note color sequence of G2-B-P-O-G1-F.
[0061] At the starburst root note 679 the symmetric portions 713 , 723 of the octaves 706 , 708 are joined. Together, these symmetric octave portions may be collapsed to form a symmetric lotus, for example a lotus with a central plume that superposes plumes of the upper and lower octaves 733 , 734 .
[0062] As used herein, applicant coins the term “normal starburst” to refer to a particular starburst, that is to a starburst including a right asymmetric lotus joined to a left asymmetric starburst at a common root note.
[0063] Turning now to the construction of triad chords, each such chord may be represented by a triangle where each edge of the triangle is an interval between notes on a harmony spiral. As explained below, these trial intervals result from the intersections of starbursts such as the starbursts described above.
[0064] FIG. 8A shows exemplary intersecting starbursts 800 A. Here, two starbursts 802 , 804 having corresponding root notes 812 , 814 are located in a harmony spiral 806 . Where the two starbursts intersect may be determined by the starburst location within the harmony spiral 806 . In various embodiments, two intersecting starbursts intersect along but a single line that extends between notes on the harmony spiral.
[0065] FIG. 8B shows a first view of the intersection 800 B of the two starbursts of FIG. 8A . Here, the intersection of first and second starbursts 802 , 804 occurs along but a single line 822 . In an exemplary intersection, the intersection occurs along a line formed by the intersection of i) a plume 824 of a first note e.g., G2 in the first starburst and ii) a plume 826 of a second note e.g., G2 in the second starburst.
[0066] FIG. 8C shows a second view of the intersection 800 C of the two starbursts of FIG. 8A . Here, only the intersecting plumes 824 , 826 are shown to better illustrate the corresponding notes 834 , 836 that the intersecting plumes extend between. As mentioned above and as further described below, these intersecting plumes may be used to determine a side of a triad chord.
[0067] FIGS. 9A-C show triads formed from intervals and composite chords formed from triads 900 A-C.
[0068] FIG. 9A shows the formation of a first triad chord 900 A. At left is a planar view 902 of three intersecting starbursts 931 - 933 within a collapsed harmony spiral 901 . At right is a perspective view 904 of the harmony spiral 901 showing the intersections of the 922 - 924 of the starbursts 931 - 933 .
[0069] Here, intersections among the starbursts are i) 931 to 932 resulting in a first interval 922 , ii) 932 to 933 resulting in a second interval 923 , and iii) 933 to 931 resulting in a third interval 924 .
[0070] These intervals are shown in the harmony spiral 901 and form a triad chord 921 , for example a triad chord including the notes F-A#-C# in a first minor chord. As will be appreciated by skilled artisans, any triad chord may be constructed as a particularly colored geometric figure within the harmony spiral 901 such that a musician visualizes the chord from chord geometry, hue, and location within the harmony spiral.
[0071] FIG. 9B shows the formation of a second triad chord 900 B. At left is a planar view 952 of three intersecting starbursts 981 - 983 within a collapsed harmony spiral 951 . At right is a perspective view 954 of the harmony spiral 951 showing the intersections of the 972 - 974 of the starbursts 981 - 983 .
[0072] In the planar view, intersections among the starbursts are i) 981 to 982 resulting in a first interval 972 , ii) 982 to 983 resulting in a second interval 973 , and iii) 983 to 981 resulting in a third interval 974 .
[0073] These intervals are shown in the harmony spiral 951 and form a triad chord 971 , for example a triad chord including the notes F-A#-C# in a second minor chord. As will be appreciated by skilled artisans, any triad chord may be constructed as a colored geometric figure within the harmony spiral 951 such that a musician visualizes the chord.
[0074] Hue variations of the intervals 922 - 924 ( 972 - 974 ) and triad chord 921 ( 971 ) are therefore associated with musical sounds such that a musician learns to “hear” the corresponding musical note combinations before the notes are actually played. Among other things, this “intuition” enables a musician to choose a next note to achieve a desired musical effect when note combination is played.
[0075] FIG. 9C shows a composite chord 900 C. Here, multiple triad chords 992 - 995 are displayed in a harmony spiral 991 . A first triad chord 992 includes the notes F#-A-C. A second triad chord 993 includes the notes F-C-A. A third triad chord 994 includes the notes E-A-D. A fourth triad chord includes the notes E-A-C. Where the triad chords have triad hues, the intersection of any two or more of these chords may result in a hue derived from the colors combined at the intersection.
[0076] FIGS. 10A-B show exemplary harmony spirals 1000 A-B. In FIG. 10A , a three dimensional harmony spiral is shown 1000 A. Displayed within the spiral 1001 are three exemplary triad chords 1002 - 1004 that illustrate the visual presentation of triad chords within a spiral harmony construct. Any of the harmony constructions mentioned herein may utilize this three dimensional geometric harmony construct. Notably, any parameterized curve might be used in place of a three dimensional spiral to describe a harmony space.
[0077] In FIG. 10B , a two dimensional harmony spiral is shown 1000 B. Displayed within the spiral 1011 are two exemplary triad chords 1012 - 1013 that illustrate the visual presentation of triad chords within a spiral harmony construct. Any of the harmony constructions mentioned herein may utilize this two dimensional geometric harmony construct. Notably, any parameterized curve might be used in place of a two dimensional spiral to describe a harmony space or plane.
[0078] In FIG. 10C , a three dimension harmony spiral is shown 1000 C. As see, a plume 1054 emanating from a root note 1056 is shown in the spiral 1052 . Here the plume hue and/or lightness varies along its length with the hue being a washed out hue at an upper octave and a deep hue near the root note, for example a washed out fuchsia at an upper octave and a deep fuchsia near the root note. Any of the harmony constructions mentioned herein may utilize this three dimensional geometric harmony construct. Notably, any parameterized curve might be used in place of a three dimensional spiral to describe a harmony space.
[0079] FIG. 11 shows a note grid 1100 . The note grid displays musical notes in a horizontal dimension and octaves in a vertical dimension against a dark background 1105 . In various embodiments, the note grid is comparable with or conveys information similar to that of a planar representation of the curved outer layer of a harmony spiral.
[0080] While various shapes, objects, pictures, or the like might be chosen, here the notes of the note grid are indicated by a geometric figure, in this case a circle 1104 . The note being played may, as here, be indicated by a marker such as a circle within the note. Here, the note being played 1102 is a D note in the fourth octave.
[0081] As seen in the column of the note being played, the notes are shaded with a light to dark gradient that lightens as the octave increase. Starburst interval hues are shown for all of the notes, behind the notes, which suggests to a musician the next sound to be selected. In each column other than the column of the note being played, frequency of the notes is indicated by note greyscale shading, from light at higher octaves to dark at lower octaves.
[0082] FIGS. 12A-B show a note grid similar to that of FIG. 11 and a corresponding triad chord 1200 A-B. As seen in the note grid of FIG. 12A , three notes are being played including notes A#-C# in the fourth octave and the note F in the third octave. Here, it is a gray inner cloud 1202 that indicates the note being played.
[0083] In the harmony spiral 1201 of FIG. 12B , the notes played are root notes of three starbursts 1281 - 1283 . Intersections of these three starbursts result in three intervals 1272 - 1274 that determine a triad chord 1271 .
[0084] As mentioned above, embodiments of the present invention provide a means for visualizing musical elements including musical notes, intervals, chords, and composite chords through the use of geometric figures with hue and/or greyscale coloration or shading indicative of the musical sound emulated. Musicians may work at composing, “listening to,” and revising musical works utilizing any of, or a combination of any of, the loti, harmony spiral, and note grid geometric constructs.
[0085] For example, a computer(s) with display device(s) may display on one or on multiple screens any or all of these geometric constructs. In an embodiment, a computer display presents on a single screen at least one of each of a three dimensional harmony spiral, a note grid corresponding to the harmony spiral, and a lotus formed from an octave of the harmony spiral.
[0086] FIG. 12C illustrates transformations to and from staff musical notation 1200 -C. In an embodiment, a computer display presents on a single screen a portion of a musical work 1232 in staff notation and one, several, or all of a lotus 1204 , a harmony parameterized curve 1206 , a second lotus 10 , and a chord type chart 1210 . In some embodiments, a note gird corresponding to the harmony parameterized curve 1206 is included in the display. In an embodiment, the display includes staff notation, a lotus, a harmony parameterized curve with one or more chords formed from normal starbursts, and a note grid corresponding to the harmony parameterized curve. Applicant notes that a “harmony parameterized curve” may be any curve, collection of joined line segments, or the like encircling a point or line multiple times and suitable for conveying the information contained by and in applicant's applicant's harmony spiral.
[0087] In the musical work: i) a first bar 1211 includes a half note E and a quarter note E and the first bar may be represented at least in part by a lotus filled with a triad chord 1231 sounding the note E; ii) a second bar 1212 includes a half note B and a quarter note B and the second bar may be represented at least in part by a lotus filled with a triad chord 1232 sounding the note B; iii) a third bar 1213 includes a dotted quarter note F, a ⅛ note G, a quarter note F and the third bar may be represented at least in part by a lotus filled with triad chords 1233 sounding the notes F and G; and, iv) a fourth bar 1214 includes a dotted half note E and the fourth bar may be represented at least in part by a lotus 1234 filled with a triad chord sounding the note E.
[0088] The first lotus 1204 provides, among other things, a chord visualization or selection tool. Having constructed a chord 1222 , skilled artisans will recognize that the included pentagon in the form of a star 1224 marks out notes that should not be played together with the triad chord 1222 . The harmony parameterized curve 1206 shows several chords including chords that span multiple octaves; as mentioned above, a corresponding note grid may also be displayed. The second lotus 1208 shows the formation of a triad chord from starbursts. These tools provide means for visualizing, composing, and editing the musical work 1212 .
[0089] Where the musical work 1212 is being composed, the first lotus 1204 and the harmony parameterized curve may be used to visualize the movement from a first note or chord to a different second note or chord as in the movement between the first and second bars 1211 - 1212 . Chord hues indicative of the sounds of chords of the chord library 1210 may aid in this or related selection(s).
[0090] In an embodiment, a user begins with a particular note or chord and utilizes geometric figures with particular hues such as notes or triad cords of a harmony parameterized curve to select a movement to a second note or chord. In an embodiment, chords within the harmony parameterized curve are formed from normal starbursts. As the user progresses, a transformation and/or decoding of the geometric figures with particular hues may be used i) to fill in the staff musical notation with the corresponding notes or ii) an associated music player may play the note(s) and/or chord(s). As such, there is a transformation of colored figures with particular hues selected using the tools to music in staff notation.
[0091] As seen above, visualization of a musical work may include transformations and/or decoding of geometric figures with particular hues presented in a harmony parameterized curve to staff musical notation and vice versa.
[0092] FIGS. 13A-H show a rhythm system 1300 A- 1300 H. As seen in rhythm system display of FIG. 13A , the rhythm may include one or more of a time circle 1302 with peripheral time increments 1304 . The time circle encloses geometric figures such as polygons, for example a polygon 1312 having vertices near, touching, or tangent to the time circle. In some embodiments, plural polygons are superimposed. A time marker 1308 marks a radial path between a time circle center 1306 and a time circle increment or increment boundary 1318 .
[0093] The time circle 1302 may be simulated or replaced by a continuous tape such a tape formed when the time circle is broken and extended to form a linear element with polygon 1312 vertices 1314 located and spaced to indicate timing.
[0094] Increments of time 1302 may be quantized such that polygon vertices 1314 sit at only particular points on the time circle, for example in the manner of a snap fit or snap to grid. As skilled artisans will understand, digital computers typically operate in a quantized manner and rational number representations of position on the time circle may therefore provide what is nearly but not actually a continuous representation of time or change of time.
[0095] Tempo is typically measured in Beats Per Minute (“BPM”) and a tempo control 1320 may be varied over time which allows a user to set a particular tempo, for example 125, and subsequently adjust this tempo as the rhythm system 1300 A runs.
[0096] In various embodiments, a circumference of or indicated on the time circle 1302 will be equal to a certain musical distance, for example a measure of music such a measure of 16 beats. Alternatively, the time circle circumference may indicate a bar of music, for example a bar of 4 beats. Here, a point in the rhythm layers may be chosen for attachment of a rhythm driver to the time circle to relate distance to beats providing a particular ration of distance to beats.
[0097] An exemplary quantization provides that between any two beats, time may be divided by a quantization factor. This factor will be a product of primes—i.e. 2̂n 1 *3̂n 2 *5̂n 3 . . . where n is 0 . . . m and where m is an integer.
[0098] Where an embodiment lacks quantization, playback may occur as with an effectively continuous tape where quantization intervals are small enough to mimic continuous playback.
[0099] In order to support song structure, time circles may be nested as in a tree like structure. For example, a large circle can represent a movement and can contain an integral number of sub-circles. These sub-circles can also contain sub-sub-circles and so on to provide a desired number of levels. This tree structure may be controlled with a layer interface to create sub-layers. At a selected point in the structure of sub-layers, a beat driver is attached to i) connect the BPM setting, ii) distance around the circles, iii) set the speed of time, and iv) determine the point where quantization will be applied. With these features, a rhythm system may represent a single movement of music, for example a movement of music with a single bpm, quantization, and rhythm structure. More complex musical representations may utilize an orchestration system that connects multiple musical movements into more complex systems and may be represented as a graph.
[0100] Linear representations of time such as a note ribbon are similarly divided by quantization and rhythm structure. In an embodiment a note ribbon represents both continuous positioning, without snap to, and quantized positions with snap to such that a user selects one or the other.
[0101] FIGS. 13B-H illustrate methods of constructing a rhythm for a musical work or a portion of a musical work 1300 B-H.
[0102] In various embodiments, a library of geometric shapes such as planar geometric shapes including one or more of polygons with a plurality of sides such as a triangle, square, pentagon, hexagon and the like is provided. These shapes include ones having vertices such as quantity n vertices where each vertex is associated with a musical voice.
[0103] FIG. 13B shows a rhythmic geometric shape in the form of a square 1314 having four vertices 1312 .
[0104] The rhythm system may be used to compose one or multiple song layers. For example, a first song layer is composed that includes four rhythmic verses wherein each verse includes four phrase sets and is represented by four phrase set circles embedded in a verse circle such that each phrase set includes four phrases and is represented by four phrase circles embedded in a phrase set circle.
[0105] FIG. 13C illustrates a musical phrase using a phrase circle. It shows a shape circle 1316 and a geometric shape in the form of a square 1314 within the phrase circle. Vertices of the square 1312 are proximate the shape circle circumference.
[0106] FIG. 13D illustrates a musical phrase set using a phrase set circle. It shows a phrase set circle 1330 with four shape circles 1316 , 1320 , 1324 , 1328 within. Respective geometric shapes include a square 1314 within the first shape circle 1316 , a triangle 1318 within the second shape circle 1320 , a square 1322 within the third shape circle 1324 , and a pentagon 1326 within the fourth shape circle 1328 .
[0107] FIG. 13E illustrates a musical verse using a verse circle. It shows a verse circle 1340 with four phrase set circles 1331 - 1334 within.
[0108] FIG. 13 F illustrates a song layer using a song layer circle. It shows a first song layer circle 1350 with four verse circles 1341 - 1344 therein. As indicated, each verse circle includes four phrase set circles 1330 and each phrase set circle includes four shape circles 1316 .
[0109] Each phrase includes four beats and is represented by a selected library shape (e.g. 1314 ) embedded in a shape circle. In a series of steps (i) verses are ordered in a selected verse sequence v 1 -v 4 , (ii) phrase sets are ordered within each verse in a selected verse-phrase set sequence ps 1 -ps 4 , (iii) phrases within each phrase set are ordered in a selected verse-phrase set-phrase sequence p 1 -p 4 , (iv) vertices within each phrase are ordered in a selected verse-phrase set-phrase-vertex sequence vx 1 -vxn.
[0110] The song layer rhythm may be played by sounding the voice of each vertex in order, beginning with (v 1 , ps 1 , p 1 , vx 1 ) and ending with (v 4 , ps 4 , p 4 , vxn).
[0111] As seen in FIG. 13G , multiple song layers may be used to compose the rhythm for a more complex musical work. In particular, first, second and third song layers 1351 - 1353 may collectively represent a musical work where the song layers are played in an order chosen by the user.
[0112] In the above rhythm composition method, the manner of composing a rhythm may further comprise the step of using the distance between adjacent vertices (see e.g., distance 1313 of FIG. 13B ) to indicate the time between sounding the voices of the adjacent vertices.
[0113] And, in the above method, the manner of composing a rhythm may further comprise the step of sounding the voice of a vertex for a time period indicated at least in part by an out-of-plane projection extending from the vertex. See for example FIG. 13 H which includes a planar geometric shape, here a triangle 1380 within a shape circle 1316 and an out-of-plane projection 1382 extending from a vertex 1381 of the triangle.
[0114] FIG. 14 shows a loop selector 1400 for use with the rhythm system 1300 A-H. The loop selector 1400 may be a rhythm system mode providing a display of one or more rhythm system elements 1300 A-H. A recording interface with the ability to play over the existing rhythm system may be attached thereto. Such recorded audio, or midi may be mapped or transformed and mapped to a loop for creating shapes with a shape selector which may be saved by name, with copy/cut/paste functions, to a time scale in the rhythm system.
[0115] Loop selection methods provide for visualization of a rhythmic structure of a musical composition on a touch screen device display 1490 such as a computer display, tablet computer display, or the like. In one such method, the steps include i) providing a sound recording of a musical work, the musical work having an underlying rhythm identifiable by events in the recording, ii) transforming the sound recording into an event recording 1402 that chronologically marks the initiation of each event 1404 such that the time span between successive events 1405 may be compared, iii) selecting a portion of the recording 1406 including a sequence of events 1411 - 1417 , iv) displaying a shape circle 1408 , v) mapping the events in the sequence of events 1411 - 1417 to corresponding locations around the perimeter of a shape circle such that the mapped events take the same order around the shape circle perimeter as in the sequence, locations of adjacent mapped events are indicative of the time span between the corresponding events in the sequence of events, and the sum of the time spans between mapped events is indicative of the time span of the selected recording portion, and vi) visualizing the rhythmic structure of the musical composition by fitting one or more polygons 1420 , 1430 to the mapped events such that polygon vertices coincide with mapped events.
[0116] The above method may further comprise wherein first and second polygons 1420 , 1430 are fitted to first and second sets of mapped events and the touch screen 1490 is used to rotate the first polygon 1420 relative to the second polygon 1430 to vary the timing between mapped events.
[0117] The above method may further comprise wherein timing changes made with the touch screen 1490 result in corresponding timing changes in the event recording 1402 .
[0118] FIGS. 15A-D show a graph methods of storing and reassembling musical works and/or portions of musical works 1500 A-D.
[0119] In particular, a method of mixing multiple musical works into continuous playable streams comprises the steps of: i) providing digital data storage accessible to a network shared by a plurality of users, see e.g., musical works stored in nodes 1 - 8 of network 1501 of FIG. 15A ; ii) in the data storage, constructing a directed graph having a set of nodes and a set of edges, see e.g., directed graph 1500 A; iii) wherein each node contains a musical work and no two nodes contain the same musical work, iv) wherein each user has access to a user specific group of plural nodes, each pair of nodes e.g. being interconnected by an edge, see e.g. nodes 1500 B of FIG. 15B accessible to user 1 , nodes 1500 C of FIG. 15C accessible to user 2 , and exemplary edges 1512 - 1526 - 1568 (interconnecting nodes 1 - 2 - 6 - 8 ), 1552 - 1527 - 1578 (interconnecting nodes 5 - 2 - 7 - 8 ) interconnecting nodes of the first and second users v) wherein each edge identifies instructions used to mix the musical works contained by the two nodes the edge interconnects, and vi) wherein musical works are mixed irrespective of user access rights to create a mixed different from the musical work found in any one node.
[0120] As seen in FIG. 15D , an exemplary mixed work includes content of nodes 5 - 2 - 6 . Here, Mix 1 includes i) a leading portion of node 5 , ii) a mix of a trailing portion of node 5 and a leading portion of node 2 , iii) a central portion of node 2 , iv) a mix of a trailing portion of node 2 and a leading portion of node 6 , and v) a trailing portion of node 6 . As mentioned above edges provide, among other things, an indication of overlapping node portions and which node portion(s) will be included and/or played in the overlap.
[0121] While various embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only, and not limitation. It will be apparent to those skilled in the art that various changes in the form and details can be made without departing from the spirit and scope of the invention. As such, the breadth and scope of the present invention should not be limited by the above-described exemplary embodiments, but should be defined only in accordance with the following claims and equivalents thereof.
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A music composition, editing, and playback system and method provides a user interface design based on geometric interpretation of music theory replacing traditional modern music notation with geometric shapes including chords represented by polygons that are colored with colors or hues.
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This is a continuation of co-pending application Ser. No. 07/235,051, filed on Aug. 23, 1988, now U.S. Pat. No. 4,897,165.
BACKGROUND OF THE INVENTION
1. Introduction
This invention relates to an electrolytic plating solution, a process for use of said solution, and to articles formed using the process and solution. In particular, the invention relates to uniformly depositing a coating of electrolytic metal on the walls of a cylindrical opening having a ratio of length to diameter greater than ten to one and a length equal to at least 0.100 inches.
2. Description of the Prior Art
Methods for electroplating articles with metal coatings are well known in the art. Such methods involve passing a current between two electrodes in a plating solution where one of the electrodes is the article to be plated. Using an acid copper plating solution for purposes of illustration, a plating solution would comprise (1) dissolved copper (cupric ions), usually copper sulfate, (2) an acid electrolyte such as sulfuric acid in an amount sufficient to impart conductivity to the bath, and (3) proprietary additives to improve efficiency of the plating reaction and the quality of the metal deposit. Such additives include surfactants, brighteners, levelers, suppressants, etc.
Electrolytic copper plating solutions are used for many industrial applications. For example, they are used in the automotive industry as base layers for subsequently applied decorative and corrosion protective coatings. They are also used in the electronics industry, particularly for the fabrication of printed circuit boards. For circuit fabrication, copper is electroplated over selected portions of the surface of a printed circuit board and onto the walls of through-holes passing between the surfaces of the circuit board base material. The walls of a through-hole are metalized to provide conductivity between circuit layers on each surface of the board.
Early efforts to make circuit boards used electrolytic copper plating solutions developed for decorative plating. However as printed circuit boards became more complex and as industry standards became more rigorous, solutions used for decorative plating were found to be inadequate for circuit board fabrication. A serious problem encountered using electrolytic copper plating solutions involved coatings of uneven thickness on the walls of the through hole with the deposits thicker at the top and bottom of the holes and thinner at the center, a condition known in the art as "dog boning". The thin deposit at the center of the through hole may lead to circuit defects and board rejection.
Dog boning is caused by a voltage drop between the top surface of the hole and the center of the hole. This potential drop is a function of current density, a ratio of the length of the hole to its diameter (aspect ratio) and board thickness. As the aspect ratio and the thickness of the board increase, dog boning becomes more severe due to a voltage drop between the surface of the board and the center of the through hole. This voltage drop is caused by a combination of factors including solution resistance; a difference in surface to hole overpotential due to mass transfer--i.e, a difference in the flow of solution through the hole compared to the movement of the solution over the surface of the board; and a charge transfer difference as a consequence of copper concentration in the hole, the copper to hydrogen ratio in the hole and the concentration of additives in the hole.
The circuit board industrY continuously seeks greater circuit densification. To increase density, the industry has resorted to multilayer circuits with through holes or interconnections passing through multiple layers. Multilayer circuit fabrication results in an overall increase in the thickness of the board and a concomitant increase in the length of an interconnection passing through the board. This means that increased circuit densification results in increased aspect ratios and hole length and an increase in the severity of the dog boning problem. For high density boards, aspect ratios typically exceed ten to one.
The prior art, exemplified by Mayer and Barbien, "Characteristics of Acid Copper Sulfate Deposits for Printed Wiring Board Applications," Plating and Surface Finishing, pp. 46 to 49, March, 1981; Malak, "Acid Copper Plating of Printed Circuits," Products Finishing, pp. 38 to 44, March, 1981; and Amadi, "Plating High Aspect Ratio Multilayer Boards," PC FAB, pp. 85 to 94, October 1987, all incorporated herein by reference, suggest that increasing the acid to metal ion ratio of an electrolytic plating solution improves plating solution throwing power and deposit distribution. The prior art teaches that the ratio may be altered, for example, by (1) increasing acid concentration while holding metal ion concentration constant or (2) by decreasing metal ion concentration while holding acid concentration constant. However, the prior art also teaches that (1) increased acid concentration may result in anode polarization with cessation of the plating reaction, and (2) decreased metal concentration resulting in exacerbation of the dog boning problem.
SUMMARY OF THE INVENTION
The subject invention is directed to a process of metal plating, a plating solution, a control device and articles formed using the aforesaid and has as its object, the elimination of dog boning in the formation of circuit boards having through-holes with an aspect ratio of at least ten to one and through hole interconnection lengths of at least 0.100 inches.
The invention is based upon the discovery that an electrolytic copper plating solution having a copper metal content varying between 1.0 and 10.0 grams per liter, preferably 3 and 8 grams per liter, and a hydrogen ion content (expressed as sulfuric acid) in an amount such that the acid to copper weight ratio varies within a range having an upper limit defined by the equation:
R=67-2.7 [X]
and a lower limit defined by the equation:
R=35-1.3 [X];
where R is the weight ratio of hydrogen ion to copper metal and X is the weight of copper metal in solution. The hydrogen ion content in the above equations is expressed as sulfuric acid since this is the acid of choice in the industry for electrolytic copper plating solutions. A preferred ratio of hydrogen ion, again expressed as sulfuric acid, to copper metal in accordance with the above equations varies between from 30:1 to 70:1 and a most preferred ratio varies between 40:1 and 60:1.
In a preferred embodiment of the invention, the copper plating solution also contains a novel surfactant that is a high molecular weight polyethylene oxide. The surfactant significantly improves throwing power within the interconnect or through-hole opening.
Solutions having copper and acid concentrations as defined above are capable of plating openings having an aspect ratio greater than ten to one and a length in excess of 0.100 inches with a uniform metal deposit throughout the length of the opening. It is also a discovery of this invention that the deposit from such a solution possess increased ductility, a desirable property for circuit manufacture.
DESCRIPTION OF THE DRAWINGS
In the drawings:
FIG. 1 is a diagrammatic representation of a plating tank containing a channel cell electrode used to measure metal deposit uniformity in a replicated interconnect;
FIG. 2 is a representation of one-half of a channel cell electrode as illustrated in FIG. 1;
FIG. 3 is a graphical representation of throwing power for a plating solution within a channel cell electrode at various acid to copper ratios.
FIG. 4 is a graphical comparison of throwing power of plating solutions within a channel cell electrode at various acid to copper ratios at 6 amps and represents data obtained in Examples 2 through 5 below;
FIG. 5 is a graphical comparison of throwing power of plating solutions within a channel cell electrode at various acid to copper ratios at 3 amps and represents data obtained in Examples 6 through 9 below;
FIG. 6 is a graphical comparison of throwing power of plating solutions within a channel cell electrode at various acid to copper ratios for a solution containing a surfactant and represents data obtained in Example 10 below; and
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The electrolytic copper plating solution of the subject invention is useful for plating copper over a variety of surfaces for a variety of commercial uses. However, the solutions are especially useful for the manufacture of double sided and multilayer printed circuit boards requiring metalized through hole or interconnection walls, especially high density printed circuit boards . For this reason, the description which follows is directed to printed circuit fabrication using the solutions of this invention.
In the fabrication of printed circuits, the starting material is typically a copper clad plastic--i.e., a copper clad epoxy panel. Using subtractive techniques for the fabrication of the board for purposes of illustration, prior to formation of a circuit, conductive through-holes are formed in the board by drilling and metallization. Processes for formation of conductive through-holes are well known in the art and described in numerous publications including U.S. Pat. No. 4,515,829 incorporated herein by reference. Electroless plating procedures are used to form a first metallic coating over the through hole wall and electrolytic copper deposition is then used to enhance the thickness of the deposit. Processes for electrolessly plating through-holes ar not part of this invention.
The next step in the process comprises electroplating copper onto the electrolessly coated hole walls using the electroplating solution of this invention. An electrolytic copper plating solution in accordance with the invention has a composition as follows:
______________________________________copper ions 1.0 to 10.0 gm/lacid sufficient for acid to copper ratio defined by above equationswater to 1 liter of solution.______________________________________
A preferred electrolytic copper plating solution in accordance with the invention has the following composition:
______________________________________copper ions 3.0 to 8.0 gm/lsulfuric acid sufficient for acid to copper ratio of 40:1 to 60:1chloride ions 20 to 100 mg/lsurfactant 25 to 1000 ppmwater to 1 liter______________________________________
For the ratio defining the acid to copper concentrations, greater latitude is possible at a lower copper content. As the copper (metal) content increases up to a maximum of 10.0 grams per liter of solution, the maximum ratio of acid to copper decreases.
In addition to the components identified above, as is known in the art, other additives may be used in the plating solution such as brighteners, exaltants, leveling agents, suppressors, etc. Such materials are well known in the art and disclosed in numerous patents including U.S. Pat. Nos. 4,347,108; 4,673,469 and 4,683,036 incorporated herein by reference.
The surfactant is a particularly useful additive in the bath of the subject invention. Preferred surfactants are high molecular weight polyethers. Examples of such ether-containing wetting agents are those having the general formula
R--O--(CH.sub.2 CH.sub.2 O).sub.n H
where R is an aryl or alkyl group containing from about two to 20 carbon atoms and n is an integer between 10 and 100,000. Preferably, R is ethylene and n is greater than 12,000. Electroplating solutions containing surfactants conforming to the above general formula and having molecular weights in excess of 500,000 are believed to be new compositions of matter.
Though lesser preferred, amine, alkanol amines, amides and polyglycol-type wetting agents known in the art are also useful surfactants. Carbowax-type wetting agents, which are polyethylene glycols having different molecular weights, are suitable. An exemplary Carbowax is Carbowax No. 1000 having a molecular weight range of from about 950 to 1,050 and containing from 20 to 24 ethoxy units per molecule. Another suitable Carbowax is Carbowax No. 4000 with a molecular weight range of from about 3000 to 3700 which contains from 68 to 85 ethoxy units per molecule.
The above surfactants are preferably added to the plating solution of the invention in an amount varying between about 1 and 2500 parts per million parts of solution and more preferably, in an amount varying between about 500 and 1500 parts per million parts of solution A metal deposit over a through hole wall is more uniform in thickness throughout the length of the hole when the plating solution contains a member of the above class of surfactants compared to a solution free of such an additive.
In accordance with the invention, greater uniformity in hole wall plating is believed to involve overpotential at the cathode. The overpotential comprises two basic components--i.e, charge transfer and mass transfer overpotential. The charge transfer overpotential is the amount of energy required to overcome the reduction of copper+2 to copper metal. The extent of the overpotential is governed primarily by the surfactant, the copper concentration and the hydrogen to copper ratio.
It is known that surfactants of the type contemplated herein suppress plating rate at a given potential. Stated otherwise, the presence of the surfactant in solution increases the charge transfer overpotential. The extent of the overpotential shift is related to the type of surfactant and its molecular weight. Greater energy is required to overcome the absorbed layer of surfactant at the cathode surface. The thickness of the surfactant layer, at a given temperature, will dictate the amount of suppression. It is believed that the greater the thickness, the better the throwing power.
The plating solutions of this invention are used in conventional manner. They are preferably used at room temperature, but may be used at elevated temperatures up to and somewhat above 150° F. In use, the plating solution is preferably used with solution agitation. This may be accomplished in a variety of ways including an air sparger, work piece agitation or by impingement. Plating is preferably conducted at a current ranging between 1 and 35 amps per square foot (ASF) depending upon the board aspect ratio and thickness.
As discussed above, the solutions of the invention are especially designed for the plating of through-holes in printed circuit manufacture where the through-hole has an aspect ratio greater than 10 to 1 and a length of 0.100 inches, preferably 0.150 inches or more. Prior to deposition of electrolytic copper onto the through-hole wall, the circuit board including the through-hole, is conventionally made conductive by electroless copper deposition. Electroless copper deposition does not constitute a part of this invention. Deposition of copper from the solution of the invention onto the wall of the through-hole results in a deposit that is uniformly thick over the full length of the hole and is characterized by excellent elongation and solder shock properties.
Much of the experimental data given below was obtained using a channel cell electrode. This is believed to be a novel instrument that replicates the plating of a through-hole. This instrument is illustrated in FIGS. 1 and 2 of the drawings.
In FIG. 1, there is shown plating tank 1 having anodes 2 suspended from bus bars 3 in plating solution 4 within tank 1. The channel cell electrode is used as a cathode 5, also suspended in solution 4. One half of the channel cell electrode is shown in greater detail in FIG. 2. With reference to FIG. 2, the electrode consists of two edge electrodes 5 and center electrode 6 separated by a background electrode 7. Edge electrodes 5 are separated from center electrodes 6 by non-conductive (epoxy) strips 8 and together with the background electrodes make up an electrode assembly 9 that rests above a rectangular thieving strip 10. Thieving 10 prevents the bottom of the cell from plating more than the top of the cell thereby resulting in greater sensitivity in use of the cell. Thieving 10 is provided with hole 11 which permits suspension of electrode 4 in bath 3 by means of rod 12. At right angles to the electrode assembly are placed two surface electrodes 13 in electrical isolation from the electrode assembly comprising edge electrodes 5, center electrode 6 and background electrode 7. Surface electrodes 13 are attached to the non conductive mounting 14 at their edges.
In use, two half channel electrodes are suspended from rod 12 into plating solution 4 contained in tank 1 with the electrode assemblies 9 in face-to-face relationship as illustrated in FIG. 1. The distance between each of the half channel electrodes can be varied while the height of the electrodes is a constant. By moving the half cell electrodes closer or further distant from each other, the ratio of the height of the electrodes to the distance between the electrodes may be varied. This height to distance ratio is analogous to the ratio of the length of a through-hole to its diameter (aspect ratio) and hence, the channel cell electrode can be used to simulate through hole plating at differing aspect ratios. Once the desired simulated aspect ratio is determined, current is passed between the electrodes. The current passing through the edge or surface electrodes and the center electrodes is recorded. The ratio of the current passing through the edge or surface electrodes to the current passing through the center electrode is a measure of solution throwing power for a test solution for a selected aspect ratio.
The throwing power data obtained using the channel cell electrode can be used to predict throwing power for a particular plating solution within a through hole or interconnect as there is a direct correlation between throwing power as measured in the channel cell electrode and throwing power within a circuit board through hole or interconnect. To use the channel cell electrode for this purpose, several test plating solutions would be used for plating within the channel cell electrode. All variables would be standardized except the ratio of acid to copper content in the test solutions. For each test solution, throwing power would be calculated by determining the ratio of the current passing through the edge or surface electrodes and the center electrodes as described above. The results would show a peak for throwing power for a given ratio. An exemplary plot of throwing power versus acid to copper ratio is shown in FIG. 3 of the drawings for a copper plating solution containing 10 grams of copper sulfate pentahydrate per liter of solution. For this test solution, optimum results were obtained at an acid ratio varying between about 45:1 and 60:1. Preferably, a ratio is selected that has a ratio varying from eighty percent of the peak to the peak ratio.
In addition to use of the channel cell electrode to replicate plating within a circuit interconnect or through hole, the channel cell electrode may be used to monitor the performance and relative concentration of acid and copper of a plating solution during its use. To use the channel cell electrode for this purpose, during plating of a printed circuit board, the channel cell electrode would be suspended in the operating plating solution or solution would be continuously passed through the channel cell electrode at a remote location during plating. Current passing through the edge or surface electrodes and the center electrode would be continuously monitored and converted to a ratio depicting throwing power. If during the plating operation, there is variance from a predetermined value for throwing power, for example, as shown in FIG. 3 of the drawings, corrections to the bath composition may be made to return the bath to its optimum operating composition.
The invention will be better understood by the examples that follow.
EXAMPLE 1
This example better illustrates the use of the channel cell electrode depicted in FIGS. 1 and 2 of the drawings. The specific channel cell electrode used had two edge electrodes measuring 1/2 by 2 inches and a center electrode measuring 1/2 by 2 inches. The channel cell electrode was placed in a plating tank measuring 20 by 14 by 5.5 inches (length to height to width) with a total volume of 25 liters. Copper anodes were placed 9 inches from the center of the channel cell electrode. A cam gear was used to permit movement of the channel cell electrode perpendicular to the anodes over a distance of from 1 to 4 inches. This arrangement provided solution agitation.
The plating tank was filled with a plating solution of the following composition:
______________________________________copper sulfate pentahydrate 10 gm/lsulfuric acid 150 gm/lchloride 50 ppmDeionized water to 1 liter______________________________________
The above bath corresponds to one having a hydrogen ion content (expressed as sulfuric acid) to copper metal content of 60 to 1 with a dissolved copper metal (cupric ion) content of 2.5 grams per liter of solution.
Prior to use of the channel cell electrode, it is prepared by polishing with 600 mesh polish. The anodes are prepared by etching with a 30% nitric acid solution until they are of a matte pink coloration. The plating tank is filled with the plating solution and the anodes are immersed into the plating solution to a height whereby the plating solution is 2 inches above the bottom of the anodes. The two halves of the channel cell electrode are spaced 3/8 inches from each other replicating an aspect ratio of in excess of 50:1. Thereafter a current of 6 amps was passed through the cell for test purposes, and the current on the edge electrodes and center electrodes of the channel cell electrode recorded. The ratio of the currents was found to be 0.30. This ratio is defined as throwing power. With sufficient data, the additional ratios can be obtained for the test solution and throwing power graphically depicted for all ratios for the test solution.
EXAMPLES 2 to 5
The procedure of Example 1 was repeated at three additional levels of dissolved copper, as shown in the following table. Acid concentration was varied for each example to give a series of acid to copper ratios for each test solution.
______________________________________ Cu.sup.++ (gm/l)______________________________________Example 2 15.0Example 3 12.5Example 4 5.0Example 5 2.5______________________________________
For each example, throwing power as defined by the ratio of the current at the edges of the channel cell electrode to the current at the center electrode of the channel cell electrode, was determined for each acid to copper ratio. The results are as shown in the following table:
______________________________________Throwing PowerRatio Example 2 Example 3 Example 4 Example 5______________________________________ 5 to 1 0.00 0.00 0.01 0.0210 to 1 0.00 0.00 0.01 0.0215 to 1 0.00 0.01 0.02 0.0320 to 1 0.01 0.02 0.09 0.1125 to 1 0.04 0.05 0.15 0.1930 to 1 0.03 0.10 0.19 0.2435 to 1 0.00 0.12 0.26 0.3240 to 1 0.00 0.11 0.30 0.3945 to 1 0.00 0.06 0.32 0.4250 to 1 0.00 0.00 0.31 0.4355 to 1 0.00 0.00 0.22 0.4260 to 1 0.00 0.00 0.14 0.41______________________________________
The results of the above examples are graphically represented in FIG. 4 of the drawings. From the graphs, it can be seen that the results obtained for example 2, an example having in excess of 10 grams of copper metal per liter of solution and outside the scope of the invention, are unsatisfactory. The peaks for examples 3 through 5 are at ratios of 35:1, 40:1 and 50:1, respectively showing that the ratio for the peak throwing power increases as the copper metal content decreases.
EXAMPLE 6
The above results may be used to select a preferred plating bath for the manufacture of circuit boards or to monitor bath performance during plating. Using FIG. 4 of the drawings for purposes of illustration, it is predictable that a copper plating bath having a copper metal content of 2.5 grams per liter should exhibit optimum performance when the acid to copper metal ratio varies between about 45:1 and 60:1. For a plating bath with a higher concentration of copper, for example, 5 grams per liter as shown in Example 4 above, optimum throwing power is obtained when the ratio of the acid to copper metal varies between about 35:1 and 55:1. With this information, the plating bath of choice can be formulated from the data obtained and monitored with the channel cell electrode so that the ratio of acid to copper metal does not vary from the preselected ranges.
The above is illustrated by the plating of holes within a circuit board that is an epoxy copper clad circuit board base material that had been metallized by electroless metal deposition. The board contained holes having a 0.013 inch diameter and had a thickness (height) of 0.240 inches or an aspect ratio of 18.5 to 1. The board was electroplated using the plating bath of example 5 with an acid to copper metal ratio of 50:1. All holes were plated with copper of uniform thickness without visible signs of dogboning.
EXAMPLES 7 to 10
The procedure of Examples 2 through 5 was repeated at 3 amps. THe results of this example are graphically represented in FIG. 5 of the drawings. From the graphs, it can be seen that the peak ratios were as follows:
______________________________________ Cupric Content PeakExample No. gm/liter Ratio______________________________________6 15.0 25:17 10.0 37:18 5.0 45:19 2.5 50:1______________________________________
The results obtained were consistent with the results given for examples 2 to 5.
EXAMPLE 11
Example 9 was repeated with a polyethylene oxide having a molecular weight of about 1,000,000 and was added to the solution in an amount of 1000 parts per million parts of solution. The results obtained are given in the following table:
______________________________________ Throwing Powerratio - acid with withoutto copper surfactant surfactant______________________________________ 5 0.00 0.0310 0.02 0.0015 0.05 0.0020 0.10 0.0025 0.20 0.0030 0.28 0.0435 0.35 0.1540 0.40 0.1945 0.44 0.2050 0.40 0.12______________________________________
The results are graphically represented in FIG. 6 of the drawings. From the drawing, it can be seen that with the surfactant used, the throwing power was essentially doubled within the desired operating range.
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A composition for electroplating copper onto a conductive surface comprising a solution soluble copper salt and an acid electrolyte, said copper salt being present in a concentration of from about 1 to 10 grams per liter of solution and said acid being present in a concentration whereby the acid to copper ratio preferably varies between about 30 to 1 and 50 to 1. The composition is especially useful for the plating of walls of cylindrical openings having a ratio of height to diameter of at least 10 to 1 and a length of at least 0.100 inches.
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TECHNICAL FIELD
[0001] The present invention relates to a carbon fiber manufacturing device for irradiating a fiber to be carbonized with microwaves to carbonize the fiber and a carbon fiber manufacturing method using the carbon fiber manufacturing device.
BACKGROUND ART
[0002] A carbon fiber is superior in specific strength and specific elastic modulus than other fibers and is industrially used widely as a reinforcing fiber or the like combined with resin by taking advantage of its lightweight characteristics and excellent mechanical characteristics.
[0003] Conventionally, the carbon fiber is manufactured in the following manner. First, a precursor fiber is subject to a pre-oxidation treatment by heating the precursor fiber in heated air at 230 to 260° C. for 30 to 100 minutes. This pre-oxidation treatment causes a cyclization reaction of the acrylic fiber, increases the oxygen binding amount, and produces a pre-oxidation fiber. This pre-oxidation fiber is carbonized, for example, under a nitrogen atmosphere, with use of a firing furnace at 300 to 800° C., and under a temperature gradient (first carbonization treatment). Subsequently, the pre-oxidation fiber is further carbonized under a nitrogen atmosphere, with use of a firing furnace at 800 to 2100° C., and under a temperature gradient (second carbonization treatment). In this manner, the carbon fiber is manufactured by heating the pre-oxidation fiber from an external portion thereof in the heated firing furnace.
[0004] In a case of manufacturing the carbon fiber in the above manner, the temperature must be raised gradually over time to avoid insufficient carbonization of an internal portion of the fiber to be carbonized. The firing furnace heating the pre-oxidation fiber from the external portion thereof has a low heat efficiency since the furnace body and the firing environment as well as the fiber to be carbonized are also heated in the firing furnace.
[0005] In recent years, manufacturing the carbon fiber by irradiating the fiber to be carbonized with microwaves and thereby heating the fiber is attempted. In heating a substance by means of the microwaves, the substance is heated from the internal portion thereof. Thus, in the case of heating the fiber to be carbonized with use of the microwaves, the internal portion and the external portion of the fiber can be carbonized uniformly, and reduction of manufacturing time for the carbon fiber is expected. In the case of heating the fiber with use of the microwaves, a target to be heated is only the fiber to be carbonized, and a high heat efficiency is thus expected.
[0006] Conventionally, as methods for manufacturing a carbon fiber with use of microwaves, methods in Patent Literature 1 to 4 are known. These methods have limitations such as providing a decompression unit for microwave-assisted plasma, adding an electromagnetic wave absorber or the like to a fiber to be carbonized, performing preliminary carbonization prior to heating by means of microwaves, requiring auxiliary heating, and requiring multiple magnetrons and are not suitable for industrial production.
[0007] Further, since the carbon fiber has a high radiation coefficient on its surface, it is difficult to sufficiently raise the firing temperature at the time of irradiating the fiber to be carbonized with microwaves and thereby carbonizing the fiber. Thus, in a case of manufacturing the carbon fiber only with irradiation with microwaves, a carbon fiber having a high carbon content rate cannot be obtained.
CITATION LIST
Patent Literatures
[0000]
Patent Literature 1: JP 2009-533562 W
Patent Literature 2: JP 2013-231244 A
Patent Literature 3: JP 2009-1468 A
Patent Literature 4: JP 2011-162898 A
SUMMARY OF INVENTION
Technical Problem
[0012] An object of the present invention is to provide a carbon fiber manufacturing device in which a fiber to be carbonized is irradiated with microwaves and thereby heated, wherein the carbon fiber manufacturing device is compact and capable of performing carbonization at atmospheric pressure without requiring an electromagnetic wave absorber or other additives or preliminary carbonization through external heating. Another problem of the present invention is to provide a carbon fiber manufacturing method for carbonizing the fiber to be carbonized at high speed with use of the carbon fiber manufacturing device.
Solution to Problem
[0013] The present inventors have discovered that a fiber to be carbonized can be carbonized sufficiently at atmospheric pressure by irradiating the fiber to be carbonized with microwaves in a cylindrical waveguide. The present inventors have also discovered that a fiber to be carbonized can be carbonized sufficiently at atmospheric pressure without requiring an electromagnetic wave absorber or other additives or preliminary carbonization through external heating by combining a preliminary carbonization furnace constituted by a rectangular waveguide and a carbonization furnace constituted by a cylindrical waveguide.
[0014] In manufacturing a carbon fiber, a fiber to be carbonized sequentially changes from an organic fiber (dielectric body) to an inorganic fiber (conductive body). That is, a microwave absorbing characteristic of a heated target gradually changes. The present inventors have discovered that a carbon fiber manufacturing device according to the present invention can manufacture a carbon fiber efficiently even in a case in which the microwave absorbing characteristic of the heated target changes.
[0015] The present inventors have further arrived at arranging a cylindrical adiabatic sleeve transmitting microwaves in a cylindrical carbonization furnace to make a fiber to be carbonized travel therein and irradiate the fiber to be carbonized with microwaves. The present inventors have still further discovered that providing a heater on a terminal end side of this adiabatic sleeve can increase the carbon content of a carbon fiber.
[0016] Since this adiabatic sleeve transmits microwaves, the fiber to be carbonized traveling therein can be heated directly. The present inventors have still further discovered that, since the adiabatic sleeve shields radiation heat generated by heating and restricts heat dissipation to keep the interior of the adiabatic sleeve at a high temperature, the carbonization speed of the fiber to be carbonized can drastically be improved.
[0017] The present inventors have arrived at the present invention based on these discoveries.
[0018] Aspects of the present invention solving the above problems are described below. The following [1] to [5] relate to a first embodiment.
[0019] [1] A carbon fiber manufacturing device including:
[0020] a cylindrical furnace including a cylindrical waveguide in which a first end is closed, a fiber outlet being formed in the first end of the cylindrical waveguide and a fiber inlet being formed in a second end of the cylindrical waveguide;
[0021] a microwave oscillator for introducing microwaves into the cylindrical furnace; and
[0022] a connection waveguide having a first end connected to the microwave oscillator side and a second end connected to a first end of the cylindrical furnace.
[0023] The carbon fiber manufacturing device in the above [1] is a carbon fiber manufacturing device including a carbonization furnace using a cylindrical waveguide as a furnace body and irradiating a fiber to be carbonized traveling in the cylindrical waveguide with microwaves at atmospheric pressure.
[0024] [2] The carbon fiber manufacturing device according to [1], wherein an electromagnetic distribution in the cylindrical furnace is in a TM mode.
[0025] [3] The carbon fiber manufacturing device according to [2], wherein an electromagnetic distribution in the connection waveguide connected to the cylindrical waveguide is in a TE mode and has an electric field component parallel to a fiber traveling direction.
[0026] In the carbon fiber manufacturing device in the above [3], an electromagnetic distribution in a cylindrical furnace is in a TM mode and has an electric field component in a parallel direction to a tube axis. Additionally, an electromagnetic distribution in a connection waveguide is in a TE mode and has an electric field component in a perpendicular direction to the tube axis. This connection waveguide is arranged with a tube axis thereof perpendicular to a tube axis of the cylindrical furnace. Thus, both the cylindrical furnace and the connection waveguide have electric field components parallel to a fiber traveling direction.
[0027] A carbon fiber manufacturing method using the carbon fiber manufacturing device in the above [1] to [3] include the following [4] and [5].
[0028] [4] A carbon fiber manufacturing method including performing carbonization by means of microwave heating having an electric field component parallel to a fiber traveling direction.
[0029] The carbon fiber manufacturing method in the above [4] is a carbon fiber manufacturing method in which a fiber to be carbonized is carbonized by means of microwave heating having an electric field component parallel to a traveling direction of the fiber to be carbonized.
[0030] [5] A carbon fiber manufacturing method using the carbon fiber manufacturing device according to [1], including:
[0031] a fiber supplying process for sequentially supplying a middle carbonized fiber having a carbon content rate of 66 to 72 mass % from the fiber inlet into the cylindrical furnace;
[0032] a microwave irradiating process for irradiating the middle carbonized fiber traveling in the cylindrical furnace with microwaves under an inert atmosphere to produce a carbon fiber; and
[0033] a carbon fiber taking-out process for sequentially taking out the carbon fiber from the fiber outlet.
[0034] The carbon fiber manufacturing method in the above [5] is a carbon fiber manufacturing method in which a middle carbonized fiber having a carbon content rate of 66 to 72 mass % is used as a fiber to be carbonized, and in which carbonization is performed in a cylindrical waveguide whose electromagnetic distribution is in a TM mode.
[0035] The following [6] to [11] relate to a second embodiment.
[0036] [6] A carbon fiber manufacturing device including:
[0037] a cylindrical furnace in which at least a first end is closed;
[0038] a microwave oscillator for introducing microwaves into the cylindrical furnace; and
[0039] a microwave-transmissive adiabatic sleeve arranged on a center axis parallel to a center axis of the cylindrical furnace to cause a fiber to be introduced from a first end thereof and to be let out from a second end thereof.
[0040] [7] The carbon fiber manufacturing device according to [6], wherein a microwave transmittance of the adiabatic sleeve is 90% or higher at an ambient temperature.
[0041] [8] The carbon fiber manufacturing device according to [6], wherein the cylindrical furnace and the microwave oscillator are connected via a connection waveguide connected to the microwave oscillator side at a first end thereof and connected to the cylindrical furnace at a second end thereof.
[0042] The carbon fiber manufacturing device in the above [6] to [8] has a microwave-transmissive adiabatic sleeve inserted in a cylindrical furnace. This adiabatic sleeve transmits microwaves, heats a fiber to be carbonized traveling therein, shields radiation heat generated by heating, and restricts heat dissipation to keep the interior of the adiabatic sleeve at a high temperature. Thus, the adiabatic sleeve accelerates carbonization of the fiber to be carbonized.
[0043] [9] The carbon fiber manufacturing device according to [6], wherein the cylindrical furnace is a cylindrical waveguide.
[0044] [10] The carbon fiber manufacturing device according to [6], wherein a heater is further arranged on the second end side of the adiabatic sleeve.
[0045] The carbon fiber manufacturing device in the above [10] is provided with a heater on a side of the adiabatic sleeve on which a fiber is let out. This heater further heats in the adiabatic sleeve a fiber to be carbonized which has been carbonized by irradiation with microwaves.
[0046] [11] A carbon fiber manufacturing method using the carbon fiber manufacturing device according to [6], including:
[0047] a fiber supplying process for sequentially supplying a middle carbonized fiber having a carbon content rate of 66 to 72 mass % into the adiabatic sleeve;
[0048] a microwave irradiating process for irradiating the middle carbonized fiber traveling in the adiabatic sleeve with microwaves under an inert atmosphere to produce a carbon fiber; and
[0049] a carbon fiber taking-out process for sequentially taking out the carbon fiber from the adiabatic sleeve.
[0050] The carbon fiber manufacturing method in the above [11] is a carbon fiber manufacturing method in which a middle carbonized fiber having a carbon content rate of 66 to 72 mass % is used as a fiber to be carbonized and is sequentially carbonized in the adiabatic sleeve.
[0051] The following [12] to [18] relate to a third embodiment. The present embodiment is a carbon fiber manufacturing device further including a preliminary carbonization furnace using a rectangular waveguide in addition to the carbon fiber manufacturing device in the above [1] or [6].
[0052] [12] A carbon fiber manufacturing device including:
[0053] (1) a first carbonization device including
[0054] a rectangular cylindrical furnace including a rectangular waveguide in which a first end is closed, a fiber outlet being formed in the first end of the rectangular waveguide and a fiber inlet being formed in a second end of the rectangular waveguide,
[0055] a microwave oscillator for introducing microwaves into the rectangular cylindrical furnace, and
[0056] a connection waveguide having a first end connected to the microwave oscillator side and a second end connected to a first end of the rectangular cylindrical furnace; and
[0057] (2) a second carbonization device including the carbon fiber manufacturing device according to [1].
[0058] The carbon fiber manufacturing device in the above [12] is a carbon fiber manufacturing device using the carbon fiber manufacturing device in the above [1] to [3] as a second carbonization furnace. In the upstream of the second carbonization furnace, a first carbonization furnace is arranged. The first carbonization furnace is a carbonization furnace using as a furnace body a rectangular waveguide in a TE mode in which an electromagnetic distribution has an electric field component in a direction perpendicular to a fiber traveling direction and irradiating a fiber to be carbonized traveling in the rectangular waveguide with microwaves at atmospheric pressure.
[0059] [13] A carbon fiber manufacturing device including:
[0060] (1) a first carbonization device including
[0061] a rectangular cylindrical furnace including a rectangular waveguide in which a first end is closed, a fiber outlet being formed in the first end of the rectangular waveguide and a fiber inlet being formed in a second end of the rectangular waveguide,
[0062] a microwave oscillator for introducing microwaves into the rectangular cylindrical furnace, and
[0063] a connection waveguide having a first end connected to the microwave oscillator side and a second end connected to a first end of the rectangular cylindrical furnace; and
[0064] (2) a second carbonization device including the carbon fiber manufacturing device according to [6].
[0065] The carbon fiber manufacturing device in the above [13] is a carbon fiber manufacturing device using the carbon fiber manufacturing device in the above [6] to [10] as a second carbonization furnace. In the upstream of the second carbonization furnace, a first carbonization furnace is arranged.
[0066] [14] The carbon fiber manufacturing device according to [12] or [13], wherein the rectangular cylindrical furnace is a rectangular cylindrical furnace provided with a partition plate partitioning an interior of the rectangular cylindrical furnace into a microwave introducing portion and a fiber traveling portion along a center axis thereof, and
[0067] wherein the partition plate has slits formed at predetermined intervals.
[0068] In the carbon fiber manufacturing device in the above [14], the interior of a rectangular waveguide is partitioned into a microwave introducing portion and a fiber traveling portion by a partition plate. Microwaves resonant in the microwave introducing portion are emitted through slits formed in the partition plate to a fiber to be carbonized traveling in the fiber traveling portion. The fiber traveling portion is provided with an electromagnetic distribution generated by microwaves leaking from the microwave introducing portion to the fiber traveling portion through the slits of the partition plate. The leakage amount of microwaves leaking to the fiber traveling portion through the slits of the partition plate increases along with an increase of the carbon content of the fiber to be carbonized.
[0069] [15] The carbon fiber manufacturing device according to [12] or [13], wherein an electromagnetic distribution in the furnace of the first carbonization device is in a TE mode, and an electromagnetic distribution in the furnace of the second carbonization device is in a TM mode.
[0070] The carbon fiber manufacturing device in the above [15] is a carbon fiber manufacturing device combining a first carbonization furnace using as a furnace body a rectangular waveguide in which an electromagnetic distribution is in a TE mode having an electric field component in a direction perpendicular to a fiber traveling direction and a second carbonization furnace using as a furnace body a cylindrical waveguide in which an electromagnetic distribution is in a TM mode.
[0071] [16] The carbon fiber manufacturing device according to [12] or [13], wherein an electromagnetic distribution in the connection waveguide is in a TE mode and has an electric field component parallel to a fiber traveling direction.
[0072] The carbon fiber manufacturing device in the above [16] is a carbon fiber manufacturing device in which an electromagnetic distribution in a connection waveguide connected to a cylindrical waveguide is in a TE mode and has an electric field component parallel to a fiber traveling direction. This connection waveguide is arranged with a tube axis thereof perpendicular to a tube axis of the cylindrical furnace. Thus, both the cylindrical furnace and the connection waveguide have electric field components parallel to the fiber traveling direction.
[0073] [17] A carbon fiber manufacturing method using the carbon fiber manufacturing device according to [12], including:
[0074] (1) a fiber supplying process for sequentially supplying a pre-oxidation fiber from the fiber inlet of the first carbonization furnace into the rectangular cylindrical furnace,
[0075] a microwave irradiating process for irradiating the pre-oxidation fiber traveling in the rectangular cylindrical furnace with microwaves under an inert atmosphere to produce a middle carbonized fiber having a carbon content rate of 66 to 72 mass %, and
[0076] a middle carbonized fiber taking-out process for sequentially taking out the middle carbonized fiber from the fiber outlet of the first carbonization furnace; and
[0077] (2) a fiber supplying process for sequentially supplying the middle carbonized fiber from the fiber inlet of the second carbonization furnace into the cylindrical furnace,
[0078] a microwave irradiating process for irradiating the middle carbonized fiber traveling in the cylindrical furnace with microwaves under an inert atmosphere to produce a carbon fiber, and
[0079] a carbon fiber taking-out process for sequentially taking out the carbon fiber from the fiber outlet of the second carbonization furnace.
[0080] The carbon fiber manufacturing method in the above [17] is a carbon fiber manufacturing method in which a pre-oxidation fiber is used as a fiber to be carbonized and is carbonized in a rectangular waveguide in which an electromagnetic distribution is in a TE mode having an electric field component in a perpendicular direction to a fiber traveling direction to produce a middle carbonized fiber having a carbon content rate of 66 to 72 mass %, and in which this middle carbonized fiber is further carbonized in a cylindrical waveguide in which an electromagnetic distribution is in a TM mode.
[0081] [18] A carbon fiber manufacturing method using the carbon fiber manufacturing device according to [13], including:
[0082] (1) a fiber supplying process for sequentially supplying a pre-oxidation fiber from the fiber inlet of the first carbonization furnace into the rectangular cylindrical furnace,
[0083] a microwave irradiating process for irradiating the pre-oxidation fiber traveling in the rectangular cylindrical furnace with microwaves under an inert atmosphere to produce a middle carbonized fiber having a carbon content rate of 66 to 72 mass %, and
[0084] a middle carbonized fiber taking-out process for sequentially taking out the middle carbonized fiber from the fiber outlet of the first carbonization furnace; and
[0085] (2) a fiber supplying process for sequentially supplying the middle carbonized fiber into the adiabatic sleeve,
[0086] a microwave irradiating process for irradiating the middle carbonized fiber traveling in the adiabatic sleeve with microwaves under an inert atmosphere to produce a carbon fiber, and
[0087] a carbon fiber taking-out process for sequentially taking out the carbon fiber from the adiabatic sleeve.
[0088] The carbon fiber manufacturing method in the above [18] is a carbon fiber manufacturing method in which a pre-oxidation fiber is used as a fiber to be carbonized and is carbonized in a rectangular waveguide in which an electromagnetic distribution is in a TE mode having an electric field component in a perpendicular direction to a fiber traveling direction to produce a middle carbonized fiber having a carbon content rate of 66 to 72 mass %, and in which this middle carbonized fiber is further carbonized in an adiabatic sleeve.
Advantageous Effects of Invention
[0089] A carbon fiber manufacturing device according to a first embodiment includes a carbonization furnace constituted by a cylindrical waveguide in which an electromagnetic distribution is in a TM mode. This carbonization furnace can perform carbonization of a fiber to be carbonized quickly in an area of the fiber having a high carbon content rate (specifically, the carbon content rate is 66 mass % or higher).
[0090] A carbon fiber manufacturing device according to a second embodiment has an adiabatic sleeve in a furnace. Thus, radiation heat generated by heating a fiber to be carbonized through irradiation with microwaves can be held in the adiabatic sleeve. As a result, carbonization of the fiber to be carbonized is accelerated. In a case in which a heater is provided at a terminal end of the adiabatic sleeve, a carbon fiber carbonized through irradiation with microwaves can be further heated. Accordingly, the quality of the carbon fiber can be further improved. In a case in which a cylindrical waveguide in which an electromagnetic distribution is in a TM mode is used as a furnace body, carbonization of the fiber to be carbonized can be performed further quickly in an area of the fiber having a high carbon content rate (specifically, the carbon content rate is 66 mass % or higher).
[0091] A carbon fiber manufacturing device according to a third embodiment has a preliminary carbonization furnace constituted by a rectangular waveguide in which an electromagnetic distribution is in a TE mode. This carbon fiber manufacturing device can perform carbonization of a fiber to be carbonized quickly in an area of the fiber having a low carbon content rate (specifically, the carbon content rate is less than 66 mass %). By combining a carbonization furnace constituted by a rectangular waveguide and a carbonization furnace constituted by a cylindrical waveguide, a carbonization process of a pre-oxidation fiber can be performed only by means of irradiation with microwaves without applying an electromagnetic wave absorber or other additives or external heating to the fiber to be carbonized. Since carbonization can be performed at atmospheric pressure in the carbon fiber manufacturing device according to each of the first to third embodiments, the fiber to be carbonized can be sequentially inserted through an inlet and an outlet formed in the furnace and carbonized.
BRIEF DESCRIPTION OF DRAWINGS
[0092] FIG. 1 illustrates a configuration example of a carbon fiber manufacturing device according to a first embodiment of the present invention.
[0093] FIG. 2 illustrates an electric field distribution on a cross-section along the line segment G-H in FIG. 1 .
[0094] FIG. 3 illustrates a configuration example of a carbon fiber manufacturing device according to a second embodiment of the present invention.
[0095] FIG. 4 illustrates an electric field distribution on a cross-section along the line segment G-H in FIG. 1 .
[0096] FIG. 5 illustrates another configuration example of a carbon fiber manufacturing device according to the second embodiment of the present invention.
[0097] FIG. 6 illustrates a configuration example of a carbon fiber manufacturing device according to a third embodiment of the present invention.
[0098] FIG. 7 illustrates an electric field distribution on a cross-section along the line segment C-D in FIG. 6 .
[0099] FIG. 8 illustrates another configuration example of a carbon fiber manufacturing device according to the third embodiment of the present invention.
[0100] FIG. 9 illustrates another configuration example of a carbonization furnace 17 of a first carbonization device.
[0101] FIG. 10 illustrates a structure of a partition plate 18 .
DESCRIPTION OF EMBODIMENTS
[0102] Hereinbelow, a carbon fiber manufacturing device and a carbon fiber manufacturing method using the same according to the present invention will be described in detail with reference to the drawings.
(1) First Embodiment
[0103] FIG. 1 illustrates a configuration example of a carbon fiber manufacturing device according to a first embodiment of the present invention. In FIG. 1 , reference sign 200 refers to a carbon fiber manufacturing device, and reference sign 21 refers to a microwave oscillator. To the microwave oscillator 21 , one end of a connection waveguide 22 is connected, and the other end of the connection waveguide 22 is connected to one end of a carbonization furnace 27 . In this connection waveguide 22 , a circulator 23 and a matching unit 25 are interposed in this order from the side of the microwave oscillator 21 .
[0104] The carbonization furnace 27 is closed at one end thereof and is connected to the connection waveguide 22 at the other end thereof. The carbonization furnace 27 is a cylindrical waveguide whose cross-section along the line segment E-F is formed in a circular hollow-centered shape. One end of the carbonization furnace 27 is provided with a fiber inlet 27 a to introduce a fiber to be carbonized into the carbonization furnace while the other end thereof is provided with a fiber outlet 27 b to take out the carbonized fiber. A short-circuit plate 27 c is arranged at an inner end portion of the carbonization furnace 27 on the side of the fiber outlet 27 b. To the circulator 23 , one end of a connection waveguide 24 is connected, and the other end of the connection waveguide 24 is connected to a dummy load 29 .
[0105] Next, operations of this carbon fiber manufacturing device 200 will be described. In FIG. 1 , reference sign 31 b refers to a fiber to be carbonized, and the fiber to be carbonized 31 b passes through an inlet 22 a formed in the connection waveguide 22 and is carried into the carbonization furnace 27 from the fiber inlet 27 a by means of a not-illustrated fiber carrying means. A microwave oscillated by the microwave oscillator 21 passes through the connection waveguide 22 and is introduced into the carbonization furnace 27 . The microwave that has reached the carbonization furnace 27 is reflected on the short-circuit plate 27 c and reaches the circulator 23 via the matching unit 25 . The reflected microwave (hereinbelow referred to as “the reflected wave” as well) turns in a different direction at the circulator 23 , passes through the connection waveguide 24 , and is absorbed in the dummy load 29 . At this time, matching is performed between the matching unit 25 and the short-circuit plate 27 c with use of the matching unit 25 , and a standing wave is generated in the carbonization furnace 27 . The fiber to be carbonized 31 b is carbonized by this standing wave and becomes a carbon fiber 31 c. It is to be noted that, at this time, the interior of the carbonization furnace 27 is at atmospheric pressure and is under an inert atmosphere by means of a not-illustrated inert gas supply means. The carbon fiber 31 c passes through the fiber outlet 27 b and is let out of the carbonization furnace 27 by means of the not-illustrated fiber carrying means. By sequentially introducing the fiber to be carbonized into the carbonization furnace 27 from the fiber inlet 27 a, irradiating the fiber to be carbonized with microwaves in the carbonization furnace 27 to carbonize the fiber, and sequentially letting the fiber out from the fiber outlet 27 b, the carbon fiber can be manufactured sequentially. The carbon fiber let out from the fiber outlet 27 b is subject to a surface treatment and a size treatment as needed. The surface treatment and the size treatment may be performed in known methods.
[0106] The carbonization furnace 27 is constituted by the cylindrical waveguide. The aforementioned microwave is introduced into the carbonization waveguide to cause a TM (Transverse Magnetic)-mode electromagnetic distribution to be formed in the carbonization furnace 27 . The TM mode is a transmission mode having an electric field component parallel to a tube axial direction of the waveguide (carbonization furnace 27 ) and a magnetic field component perpendicular to the electric field. FIG. 2 illustrates an electric field distribution on a cross-section along the line segment G-H. In this carbon fiber manufacturing device, an electric field component 28 parallel to a traveling direction of the fiber to be carbonized 31 b is formed, and the fiber to be carbonized 31 b is thereby carbonized. In general, the fiber to be carbonized can be heated more strongly in the TM mode than in a below-mentioned TE mode.
[0107] Although the frequency of the microwave is not particularly limited, 915 MHz or 2.45 GHz is generally used. Although the output of the microwave oscillator is not particularly limited, 300 to 2400 W is appropriate, and 500 to 2000 W is more appropriate.
[0108] The shape of the cylindrical waveguide used as the carbonization furnace is not particularly limited as long as the TM-mode electromagnetic distribution can be formed in the cylindrical waveguide. In general, the length of the cylindrical waveguide is preferably 260 to 1040 mm and is more preferably a multiple of a resonance wavelength of the microwave. The inside diameter of the cylindrical waveguide is preferably 90 to 110 mm and preferably 95 to 105 mm. The material for the cylindrical waveguide is not particularly limited and is generally a metal such as stainless steel, iron, and copper.
[0109] To heat and carbonize the fiber to be carbonized in the TM mode, the carbon content in the fiber to be carbonized is preferably 66 to 72 mass % and more preferably 67 to 71 mass %. In a case in which the carbon content is less than 66 mass %, the fiber to be carbonized is too low in conductivity and easily ruptures when the fiber is heated in the TM mode. In a case in which the carbon content is more than 72 mass %, the conductive fiber to be carbonized existing around the entrance of the carbonization furnace 27 absorbs or reflects microwaves. Thus, introduction of microwaves from the connection waveguide 22 into the carbonization furnace 27 is easily prevented. As a result, since carbonization inside the connection waveguide 22 is accelerated, the degree of progression of carbonization inside the carbonization furnace 27 is lowered, and as a whole, carbonization of the fiber to be carbonized tends to be insufficient.
[0110] The carrying speed of the fiber to be carbonized in the carbonization furnace is preferably 0.05 to 10 m/min., more preferably 0.1 to 5.0 m/min., and especially preferably 0.3 to 2.0 m/min.
[0111] The carbon content rate of the carbon fiber obtained in this manner is preferably 90 mass % and more preferably 91 mass %.
(2) Second Embodiment
[0112] FIG. 3 illustrates a configuration example of a carbon fiber manufacturing device according to a second embodiment of the present invention. In FIG. 3 , reference sign 400 refers to a carbon fiber manufacturing device. Identical components to those in FIG. 1 are shown with the same reference signs, and description of the duplicate components is omitted. Reference sign 47 refers to a carbonization furnace. The carbonization furnace 47 is a cylindrical tube closed at one end thereof and connected to the connection waveguide 22 at the other end thereof. In this carbonization furnace 47 , an adiabatic sleeve 26 having a center axis parallel to a tube axis of the carbonization furnace 47 is arranged. One end of the adiabatic sleeve 26 is provided with a fiber inlet 47 a to introduce a fiber to be carbonized into the carbonization furnace while the other end thereof is provided with a fiber outlet 47 b to take out the carbonized fiber. A short-circuit plate 47 c is arranged at an inner end portion of the carbonization furnace 47 on the side of the fiber outlet 47 b.
[0113] Next, operations of this carbon fiber manufacturing device 400 will be described. In FIG. 3 , reference sign 31 b refers to a fiber to be carbonized, and the fiber to be carbonized 31 b passes through the inlet 22 a formed in the connection waveguide 22 and is carried into the adiabatic sleeve 26 in the carbonization furnace 47 from the fiber inlet 47 a by means of a not-illustrated fiber carrying means. As with the first embodiment, the fiber to be carbonized 31 b is carbonized in the carbonization furnace 47 and becomes the carbon fiber 31 c.
[0114] The fiber to be carbonized 31 b is irradiated with microwaves and is thereby heated. At this time, since the adiabatic sleeve 26 shields radiation heat generated by heating of the fiber to be carbonized 31 b and restricts heat dissipation, the interior of the adiabatic sleeve 26 is kept at a high temperature. The interior of the adiabatic sleeve 26 is at atmospheric pressure and is under an inert atmosphere by means of a not-illustrated inert gas supply means.
[0115] The carbon fiber 31 c passes through the fiber outlet 47 b and is let out of the carbonization furnace 47 by means of the not-illustrated fiber carrying means. By sequentially introducing the fiber to be carbonized into the adiabatic sleeve 26 from the fiber inlet 47 a, irradiating the fiber to be carbonized with microwaves in the adiabatic sleeve 26 to carbonize the fiber, and sequentially letting the fiber out from the fiber outlet 47 b, the carbon fiber can be manufactured sequentially.
[0116] The frequency of the microwave is similar to that in the first embodiment.
[0117] The adiabatic sleeve 26 is preferably cylindrical. The inside diameter of the cylindrical adiabatic sleeve 26 is preferably 15 to 55 mm and more preferably 25 to 45 mm. The outside diameter of the adiabatic sleeve 26 is preferably 20 to 60 mm and more preferably 30 to 50 mm. The length of the adiabatic sleeve 26 is not particularly limited and generally 100 to 2500 mm. The material for the adiabatic sleeve 26 needs to be a material transmitting microwaves. The microwave transmittance at an ambient temperature (25° C.) is preferably 90 to 100% and more preferably 95 to 100%. Examples of such a material are mixtures of alumina, silica, magnesia, and the like. Each end of the adiabatic sleeve 26 may be provided with a material absorbing microwaves to prevent leakage of the microwaves.
[0118] An outer circumferential portion of the adiabatic sleeve 26 on the fiber outlet side, which is a furnace body internal portion or a furnace body external portion of the carbonization furnace 27 , is preferably provided with a heater. FIG. 5 illustrates a configuration example of a carbon fiber manufacturing device provided with a heater. In FIG. 5 , reference sign 401 refers to a carbon fiber manufacturing device, and reference sign 30 refers to a heater. The heater 30 is arranged at an outer circumferential portion of the adiabatic sleeve 26 on the side of the fiber outlet 47 b at an external portion of the carbonization furnace 47 . The other configuration is similar to that in FIG. 3 .
[0119] The carbonization furnace 47 is preferably cylindrical. The inside diameter of the cylindrical carbonization furnace 47 is preferably 90 to 110 mm and more preferably 95 to 105 mm. The length of the carbonization furnace 47 is preferably 260 to 2080 mm. The material for the carbonization furnace 47 is similar to that in the first embodiment.
[0120] As the carbonization furnace 47 , a waveguide is preferably used, and a cylindrical waveguide enabling a TM-mode electromagnetic distribution to be formed in the carbonization furnace 47 is more preferably used. The aforementioned microwave is introduced into the carbonization waveguide to cause the TM (Transverse Magnetic)-mode electromagnetic distribution to be formed in the carbonization furnace 47 . FIG. 4 illustrates an electric field distribution on a cross-section along the line segment G-H. In this carbon fiber manufacturing device, an electric component 38 parallel to a traveling direction of the fiber to be carbonized 31 b is formed, and the fiber to be carbonized 31 b is thereby heated.
[0121] The carrying speed of the fiber to be carbonized in the carbonization furnace is similar to that in the first embodiment.
(3) Third Embodiment
[0122] A third embodiment of the present invention is a carbon fiber manufacturing device in which a preliminary carbonization furnace using microwaves is further arranged in the upstream of the carbon fiber manufacturing device according to the above first or second embodiment. FIG. 6 illustrates a configuration example of a carbon fiber manufacturing device in which a preliminary carbonization furnace using microwaves is further arranged in the upstream of the carbon fiber manufacturing device according to the first embodiment. Identical components to those in FIG. 1 are shown with the same reference signs, and description of the duplicate components is omitted. In FIG. 6 , reference sign 300 refers to a carbon fiber manufacturing device, and reference sign 100 refers to a first carbonization device. Reference sign 200 refers to a second carbonization device and is equal to the carbon fiber manufacturing device 200 according to the above first embodiment (in the third embodiment, reference sign 200 also refers to “a second carbonization device”). Reference sign 11 refers to a microwave oscillator. To the microwave oscillator 11 , one end of a connection waveguide 12 is connected, and the other end of the connection waveguide 12 is connected to one end of a carbonization furnace 17 . In this connection waveguide 12 , a circulator 13 and a matching unit 15 are interposed in this order from the side of the microwave oscillator 11 .
[0123] The carbonization furnace 17 is a rectangular waveguide which is closed at both ends thereof and whose cross-section along the line segment A-B is formed in a rectangular hollow-centered shape. One end of the carbonization furnace 17 is provided with a fiber inlet 17 a to introduce a fiber to be carbonized into the carbonization furnace while the other end thereof is provided with a fiber outlet 17 b to take out the carbonized fiber. A short-circuit plate 17 c is arranged at an inner end portion of the carbonization furnace 17 on the side of the fiber outlet 17 b. To the circulator 13 , one end of a connection waveguide 14 is connected, and the other end of the connection waveguide 14 is connected to a dummy load 19 .
[0124] Next, operations of this carbon fiber manufacturing device 300 will be described. In FIG. 6 , reference sign 31 a refers to a pre-oxidation fiber, and the pre-oxidation fiber 31 a passes through an inlet 12 a formed in the connection waveguide 12 and is carried into the carbonization furnace 17 from the fiber inlet 17 a by means of a not-illustrated fiber carrying means. A microwave oscillated by the microwave oscillator 11 passes through the connection waveguide 12 and is introduced into the carbonization furnace 17 . The microwave that has reached the carbonization furnace 17 is reflected on the short-circuit plate 17 c and reaches the circulator 13 via the matching unit 15 . The reflected wave turns in a different direction at the circulator 13 , passes through the connection waveguide 14 , and is absorbed in the dummy load 19 . At this time, matching is performed between the matching unit 15 and the short-circuit plate 17 c with use of the matching unit 15 , and a standing wave is generated in the carbonization furnace 17 . The pre-oxidation fiber 31 a is carbonized by this standing wave and becomes a middle carbonized fiber 31 b. It is to be noted that, at this time, the interior of the carbonization furnace 17 is at atmospheric pressure and is under an inert atmosphere by means of a not-illustrated inert gas supply means. The middle carbonized fiber 31 b passes through the fiber outlet 17 b and is let out of the carbonization furnace 17 by means of the not-illustrated fiber carrying means. The middle carbonized fiber 31 b is thereafter transmitted to the carbon fiber manufacturing device (second carbonization device) 200 described in the first embodiment, and the carbon fiber 31 c is manufactured.
[0125] The carbonization furnace 17 is constituted by the rectangular waveguide. The aforementioned microwave is introduced into the carbonization waveguide to cause a TE (Transverse Electric)-mode electromagnetic distribution to be formed in the carbonization furnace 17 . The TE mode is a transmission mode having an electric field component perpendicular to a tube axial direction of the waveguide (carbonization furnace 17 ) and a magnetic field component perpendicular to the electric field. FIG. 7 illustrates an electric field distribution on a cross-section along the line segment C-D. In this carbon fiber manufacturing device, an electric field component 32 perpendicular to the fiber to be carbonized 31 a traveling in the carbonization furnace 17 is formed, and the fiber to be carbonized 31 a is thereby carbonized.
[0126] The shape of the rectangular waveguide used as the carbonization furnace is not particularly limited as long as the TE-mode electromagnetic distribution can be formed in the rectangular waveguide. In general, the length of the rectangular waveguide is preferably 500 to 1500 mm. The aperture of the cross-section orthogonal to the tube axis of the rectangular waveguide preferably has its longer side of 105 to 115 mm and its shorter side of 50 to 60 mm. The material for the rectangular waveguide is not particularly limited and is generally a metal such as stainless steel, iron, and copper.
[0127] The frequency of the microwave is one described in the first embodiment. The output of the microwave oscillator of the first carbonization device 100 is not particularly limited, 300 to 2400 W is appropriate, and 500 to 2000 W is more appropriate.
[0128] The carbon content in the middle carbonized fiber obtained by heating the pre-oxidation fiber in the TE mode is preferably 66 to 72 mass %. In a case in which the carbon content is less than 66 mass %, the fiber to be carbonized is too low in conductivity and easily ruptures when the fiber is heated in the TM mode in the second carbonization device 200 . In a case in which the fiber is heated in the TE mode with the carbon content of over 72 mass %, abnormal heating occurs locally, and the fiber easily ruptures. Further, the conductive fiber to be carbonized existing around the entrance of the carbonization furnace 27 in the second carbonization device 200 absorbs or reflects microwaves, and introduction of microwaves from the connection waveguide 22 into the carbonization furnace 27 is easily prevented. Since carbonization inside the connection waveguide 22 is accelerated, the degree of progression of carbonization inside the carbonization furnace 27 is lowered, and as a whole, carbonization of the fiber to be carbonized tends to be insufficient.
[0129] The carrying speed of the fiber to be carbonized in the first carbonization device is preferably 0.05 to 10 m/min., more preferably 0.1 to 5.0 m/min., and especially preferably 0.3 to 2.0 m/min. The carrying speed of the fiber to be carbonized in the second carbonization device is one described in the first embodiment.
[0130] FIG. 8 illustrates a configuration example of a carbon fiber manufacturing device in which a first carbonization device using microwaves is further arranged in the upstream of the carbon fiber manufacturing device according to the second embodiment. Identical components to those in FIGS. 3 and 6 are shown with the same reference signs, and description of the duplicate components is omitted. In FIG. 8 , reference sign 500 refers to a carbon fiber manufacturing device, reference sign 100 refers to a first carbonization device, and reference sign 400 refers to the aforementioned carbon fiber manufacturing device 400 . Operations of this carbon fiber manufacturing device are similar to those of the carbon fiber manufacturing device 300 .
[0131] In the first carbonization device 100 of the carbon fiber manufacturing devices 300 and 500 according to the present invention, the interior of the first carbonization furnace 17 is preferably provided with a partition plate partitioning the interior into a microwave introducing portion and a fiber traveling portion along a center axis thereof.
[0132] FIG. 9 illustrates another configuration example of the carbonization furnace 17 of the first carbonization device. The interior of the carbonization furnace 17 is provided with a partition plate 18 partitioning the interior into a microwave standing portion 16 a and a fiber traveling portion 16 b along a center axis thereof. FIG. 10 illustrates a structure of the partition plate 18 . The partition plate 18 is provided with a plurality of slits 18 a serving as through holes at predetermined intervals. Each of the slits 18 a functions to leak microwaves from the microwave introducing portion 16 a to the fiber traveling portion 16 b. The connection waveguide 12 is connected to the side of the microwave introducing portion 16 a, and standing waves in the microwave introducing portion 16 a leak via the slits 18 a formed in the partition plate 18 to the side of the fiber traveling portion 16 b. The leakage amount varies depending on the dielectric constant of the fiber traveling in the fiber traveling portion 16 b. That is, the amount of microwaves to be absorbed in the fiber gradually increases along with progression of carbonization. Thus, carbonization progresses by means of dielectric heating in an initial stage of carbonization of the pre-oxidation fiber 31 a and by means of resistance heating in a progressed stage of carbonization of the pre-oxidation fiber 31 a. Accordingly, an irradiation state of microwaves can automatically be changed in accordance with the degree of carbonization of the fiber to be carbonized. Thus, carbonization of the fiber to be carbonized can be performed more efficiently.
[0133] A distance 18 b between center points of the slits is preferably 74 to 148 mm and is preferably a multiple of ½ of a resonance wavelength of the microwave.
EXAMPLES
[0134] Hereinbelow, the present invention will be described further in detail by examples. The present invention is not limited to these examples.
[0135] In the following examples, a pre-oxidation fiber refers to an oxidized PAN fiber having a carbon content rate of 60 mass %, and a middle carbonized fiber refers to a middle carbonized PAN fiber having a carbon content rate of 66 mass %. As for evaluation of “Carbonization Determination,” a case in which the carbon content rate of a carbonized fiber is 90 mass % or higher is graded as ◯ while a case in which it is less than 90 mass % is graded as ×. As for evaluation of “Process Stability,” a case in which the fiber does not rupture during carbonization is graded as ◯ while a case in which the fiber ruptures is graded as ×. As for “Output” of microwaves, “High” means 1500 W, “Middle” means 1250 W, and “Low” means 1000 W. As for “Carrying Speed Ratio of Fiber to be Carbonized,” the ratio when the carrying speed in a conventional method is one time is shown. “Single Fiber Tensile Strength” is determined through a single fiber tensile strength test, and as for evaluation thereof, tensile strength of 3 GPa or higher is graded as ◯ while tensile strength of less than 3 GPa is graded as ×.
Example 1
[0136] The carbon fiber manufacturing device according to the first embodiment (the frequency of the microwave oscillator was 2.45 GHz, and the output was 1200 W) was prepared. As the carbonization furnace, a cylindrical waveguide having an inside diameter of 98 mm, an outside diameter of 105 mm, and a length of 260 mm was used. Microwaves were introduced into the carbonization furnace under a nitrogen gas atmosphere to form a TM-mode electromagnetic distribution. A middle carbonized fiber was made to travel at 0.2 m/min., and was carbonized in this carbonization furnace to produce a carbon fiber. The carbon content rate of the produced carbon fiber was 90 mass %, and no rupture of the fiber was found.
Example 2
[0137] The carbon fiber manufacturing device according to the second embodiment (in the first carbonization device, the frequency of the microwave oscillator was 2.45 GHz, and the output was 500 W, and in the second carbonization device, the frequency of the microwave oscillator was 2.45 GHz, and the output was 1200 W) was prepared. As the first carbonization furnace, a rectangular waveguide whose cross-section was formed in a rectangular shape with a longer side of 110 mm and a shorter side of 55 mm, which had a hollow-centered structure, and which was 1000 mm in length was used. In the rectangular waveguide, a partition plate provided with slits having a distance, between center points of the slits, of 74 mm, was arranged to split the interior of the rectangular waveguide into two. As the second carbonization device, a cylindrical waveguide having an inside diameter of 98 mm, an outside diameter of 105 mm, and a length of 260 mm was used. Microwaves were introduced into the carbonization furnace under a nitrogen gas atmosphere to form a TE-mode electromagnetic distribution in the first carbonization furnace and a TM-mode electromagnetic distribution in the second carbonization furnace. A pre-oxidation fiber was made to travel at 0.2 m/min. and was carbonized in the first carbonization device and the second carbonization device in this order to produce a carbon fiber. The carbon content rate of the produced carbon fiber was 93 mass %, and no rupture of the fiber was found.
Comparative Example 1
[0138] Carbonization was performed in a similar manner to that in Example 1 except that a rectangular waveguide whose cross-section was formed in a rectangular shape with a longer side of 110 mm and a shorter side of 55 mm, which had a hollow-centered structure, and which was 1000 mm in length was used as the carbonization furnace. The carbon content rate of a produced carbon fiber was 91 mass %, but partial rupture was found in the fiber.
Comparative Example 2
[0139] When carbonization was performed in a similar manner to that in Example 1 except that the fiber to be carbonized that was made to travel in the carbonization furnace was changed to a pre-oxidation fiber, a produced fiber ruptured.
Comparative Example 3
[0140] Carbonization was performed in a similar manner to that in Example 1 except that a rectangular waveguide whose cross-section was formed in a rectangular shape with a longer side of 110 mm and a shorter side of 55 mm, which had a hollow-centered structure, and which was 1000 mm in length was used as the carbonization furnace, and that the fiber to be carbonized that was made to travel in the carbonization furnace was changed to a pre-oxidation fiber. Carbonization of a produced fiber was insufficient.
Comparative Example 4
[0141] Carbonization was performed in a similar manner to that in Example 1 except that a rectangular waveguide whose cross-section was formed in a rectangular shape with a longer side of 110 mm and a shorter side of 55 mm, which had a hollow-centered structure, which was 1000 mm in length, and in which a partition plate provided with slits having a distance, between center points of the slits, of 74 mm, was arranged to split the interior of the rectangular waveguide into two was used as the carbonization furnace. A middle carbonized fiber suitable for being supplied to the second carbonization device was obtained.
Reference Example 1
[0142] An electric furnace (heating furnace using no microwaves) was used as the carbonization furnace, and a pre-oxidation fiber was carbonized in a known method to produce a carbon fiber. The carbon content rate of the produced carbon fiber was 95 mass %, and no rupture of the fiber was found.
[0143] The results of the above examples are shown in Table 1. When the carbon fiber manufacturing device according to the present invention is used, a carbon fiber having an equivalent carbon content rate to that in a conventional external heating method can be manufactured. As for the manufacturing speed of the carbon fiber, the carbon fiber manufacturing device according to the present invention is three or more times as fast as the conventional carbon fiber manufacturing device.
[0000]
TABLE 1
Carrying Speed
Carbon Content
of Fiber to be
Rate of
Heating
Electromagnetic
Fiber to be
Carbonized
Carbonized Fiber
Carbonization
Process
Method
Distribution
Carbonized
(m/min.)
(mass %)
Determination
Stability
Example 1
Microwave
TM
Middle
0.2
91
∘
∘
Carbonized
Fiber
Example 2
Microwave
TE + TM
Pre-oxidation
0.2
93
∘
∘
fiber
Comparative
Microwave
TE
Middle
0.2
91
∘
x
Example 1
Carbonized
Fiber
Comparative
Microwave
TM
Pre-oxidation
0.2
—
x
x
Example 2
fiber
Comparative
Microwave
TE
Pre-oxidation
0.2
63
—
x
Example 3
fiber
Comparative
Microwave
TE
Pre-oxidation
0.2
69
—
∘
Example 4
fiber
Reference
External
—
Pre-oxidation
0.06
95
∘
∘
Example 1
Heating
fiber
Reference Example 2
[0144] An electric furnace (heating furnace using no microwaves) whose aperture of the cross-section orthogonal to the fiber traveling direction was formed in a rectangular shape with a longer side of 110 mm and a shorter side of 55 mm, which had a hollow-centered structure, and which was 260 mm in furnace length was used as the carbonization furnace, and a middle carbonized fiber was made to travel therein at 0.1 m/min. and was carbonized to produce a carbon fiber. The carbon content rate of the produced carbon fiber was 95 mass %, and no rupture of the fiber was found.
Example 3
[0145] The carbon fiber manufacturing device illustrated in FIG. 3 (the frequency of the microwave oscillator was 2.45 GHz) was prepared. As the carbonization furnace, a cylindrical waveguide having an inside diameter of 98 mm, an outside diameter of 105 mm, and a length of 260 mm was used. As the adiabatic sleeve, a cylindrical white porcelain tube having an inside diameter of 35 mm, an outside diameter of 38 mm, and a length of 250 mm (microwave transmittance=94%) was used. Microwaves were introduced into the carbonization furnace under a nitrogen gas atmosphere to form a TM-mode electromagnetic distribution. The output of the microwave oscillator was set to “Low.” A middle carbonized fiber was made to travel at 0.3 m/min. and was carbonized in this carbonization furnace to produce a carbon fiber. The carbon content rate of the produced carbon fiber was 91 mass %, and no rupture of the fiber was found. The evaluation result is shown in Table 2.
Examples 4 and 5
[0146] In each of Examples 4 and 5, a similar procedure to that in Example 3 was performed except that the output of the microwave oscillator was changed as described in Table 2 to obtain a carbon fiber. The results are shown in Table 2.
Example 6
[0147] A similar procedure to that in Example 3 was performed except that the heater was arranged at the outer circumferential portion of the adiabatic sleeve extended 10 cm outward from the fiber outlet to obtain a carbon fiber. The result is shown in Table 2.
Example 7
[0148] The carbon fiber manufacturing device illustrated in FIG. 3 (the frequency of the microwave oscillator was 2.45 GHz) was prepared. As the carbonization furnace, a rectangular waveguide was used. The rectangular waveguide was 1000 mm in length, and the size of the aperture of the cross-section orthogonal to the tube axis thereof was 110×55 mm. As the adiabatic sleeve, a cylindrical white porcelain tube having an inside diameter of 35 mm, an outside diameter of 38 mm, and a length of 250 mm was used. Microwaves were introduced into the carbonization furnace under a nitrogen gas atmosphere to form a TE-mode electromagnetic distribution. The output of the microwave oscillator was set to “High.” A middle carbonized fiber was made to travel at 0.1 m/min. and was carbonized in this carbonization furnace to produce a carbon fiber. The carbon content rate of the produced carbon fiber was 93 mass %, and no rupture of the fiber was found. The evaluation result is shown in Table 2.
Comparative Examples 5 to 7
[0149] In each of Comparative Examples 5 to 7, the same carbon fiber manufacturing device as that in Example 3 was used except that no adiabatic sleeve was provided. A similar procedure to that in Example 3 was performed except that the output of the microwave oscillator was changed as described in Table 2 to obtain a carbon fiber. The results are shown in Table 2.
Comparative Example 8
[0150] The same carbon fiber manufacturing device as that in Example 3 was used except that no adiabatic sleeve was provided. A similar procedure to that in Example 3 was performed except that the carrying speed of the middle carbonized fiber was set to 0.1 m/min. to obtain a carbon fiber. The result is shown in Table 2.
Comparative Example 9
[0151] The same carbon fiber manufacturing device as that in Example 7 was used except that no adiabatic sleeve was provided, and a similar procedure to that in Example 7 was performed to obtain a carbon fiber. The result is shown in Table 2.
[0152] The carbon fiber manufacturing device according to the present invention provided with the adiabatic sleeve can cause the carbon content amount of the fiber to be carbonized to be larger than that in a carbon fiber manufacturing device provided with no adiabatic sleeve. This can accelerate the carrying speed of the carbon fiber and can improve a production efficiency.
[0000]
TABLE 2
Carrying
Carbon Content
Adiabatic
Speed Ratio
Rate of
Single
Sleeve
of Fiber
Carbonized
Fiber
Heating
Electromagnetic
Provided/Not
to be
Fiber
Tensile
Method
Distribution
Output
Provided
Carbonized
(mass %)
Strength
Reference
External
—
—
Not Provided
One Time
95
∘
Example 2
Heating
Example 3
Microwave
TM
Low
Provided
Three Times
91
∘
Example 4
Microwave
TM
Middle
Provided
Three Times
92
∘
Example 3
Microwave
TM
High
Provided
Three Times
94
∘
Example 6
Microwave
TM
High
Provided
Three Times
95
∘
Example 7
Microwave
TE
High
Provided
One Time
93
∘
Comparative
Microwave
TM
Low
Not Provided
Three Times
77
x
Example 5
Comparative
Microwave
TM
Middle
Not Provided
Three Times
78
x
Example 6
Comparative
Microwave
TM
High
Not Provided
Three Times
82
x
Example 7
Comparative
Microwave
TM
High
Not Provided
One Time
90
x
Example 8
Comparative
Microwave
TE
High
Not Provided
One Time
89
x
Example 9
REFERENCE SIGNS LIST
[0000]
100 . . . first carbonization device (preliminary carbonization device)
200 , 400 . . . carbon fiber manufacturing device (second carbonization device)
300 , 500 . . . carbon fiber manufacturing device
11 , 21 . . . microwave oscillator
12 , 14 , 22 , 24 . . . connection waveguide
12 a, 22 a . . . inlet
13 , 23 . . . circulator
15 , 25 . . . matching unit
16 a . . . microwave introducing portion
16 b . . . fiber traveling portion
17 , 27 , 47 . . . carbonization furnace
17 a . . . fiber inlet
17 b . . . fiber outlet
17 c . . . short-circuit plate
18 . . . partition plate
18 a . . . slit
18 b . . . distance between center points of slits
26 . . . adiabatic sleeve
27 a, 47 a . . . fiber inlet
27 b, 47 b . . . fiber outlet
27 c, 47 c . . . short-circuit plate
28 . . . electric field in cylindrical waveguide
19 , 29 . . . dummy load
30 . . . heater
31 a . . . pre-oxidation fiber
31 b . . . middle carbonized fiber
31 c . . . carbon fiber
32 . . . electric field in rectangular waveguide
36 . . . electric field in rectangular waveguide
38 . . . electric field in cylindrical waveguide
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The problem of the present invention is to provide a carbon fiber manufacturing device in which fiber to be carbonized is irradiated with microwaves and thereby heated, wherein the carbon fiber manufacturing device is compact and capable of performing carbonization at atmospheric pressure without requiring an electromagnetic wave absorber or other additives or preliminary carbonization through external heating. This carbon fiber manufacturing device ( 200 ) includes: a cylindrical furnace ( 27 ) comprising a cylindrical waveguide in which one end is closed, a fiber outlet ( 27 b ) being formed in the one end of the cylindrical waveguide and a fiber inlet ( 27 a ) being formed in the other end of the cylindrical waveguide; a microwave oscillator ( 21 ) for introducing microwaves into the cylindrical furnace ( 27 ); and a connection waveguide ( 22 ) having one end connected to the microwave oscillator ( 21 ) side and the other end connected to one end of the cylindrical furnace ( 27 ).
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BACKGROUND OF THE INVENTION
[0001] Field of the Invention
[0002] The present invention relates to devices that removes dust particles from gases, and more specifically to a particular category of such devices called wet scrubbers, and more specifically to wet scrubbers with nozzles, and even more specifically to wet scrubbers with self-cleaning nozzles.
[0003] The concern of this invention is with air pollution resulting from the emission into the atmosphere of particulate matter and other contaminants. As noted in the Federal Register of Dec. 27, 1996 (Vol. 61, No. 25), “[t]he primary goal of the Clean Air Act is to enhance the quality of the Nation's air resources and to promote the public health and welfare and the productive capacity of its population.”
[0004] Particulate matter is made up of tiny particles in the atmosphere that can be solid or liquid (except for water or ice) and is produced by a wide variety of natural and manmade sources. Particulate matter includes dust, dirt, soot, smoke and tiny particles of pollutants. Some particles attract and combine with amounts of water so small that they do not fall to the ground as rain. Major sources of particulate pollution are factories, power plants, trash incinerators, motor vehicles, construction activity, fires, and natural windblown dust. Particles below 10 microns in size (about seven times smaller than the width of a human hair) are more likely to travel deep in the respiratory system, and be deposited deep in the lungs where they can be trapped on membranes. If trapped, they can cause excessive growth of fibrous lung tissue, which leads to permanent injury. Children, the elderly, and people suffering from heart or lung disease are especially at risk. Particles of 10 microns or less are also referred to as PM10.
[0005] Electrostatic precipitators, which have been used for particulate control since 1923, use electrical fields to remove particulate from boiler flue gas. Inasmuch as precipitators act only on the particulate to be removed, and only minimally hinder flue gas flow, they have very low-pressure drops, and thus low energy requirements and operating costs. The main drawback of a conventional electrostatic precipitator, apart from requiring a high voltage supply, is that the contaminants collected on the collecting electrode tend to adhere thereto. This makes it necessary, on occasion, to shut down the precipitator in order to scale off the accumulated dirt.
[0006] Fabric filter collectors are conceptually simple: by passing flue gas through a tightly woven fabric, particulate in the flue gas will be collected on the fabric by sieving and other mechanisms. The dust cake, which forms on the filter from the collected particulate, can contribute significantly to collection efficiency. Practical application of fabric filters requires the use of a large fabric area in order to avoid an unacceptable pressure drop across the fabric.
[0007] Cyclones use centrifugal force to separate particulate from gas streams, and belong to the broader family of mechanical collectors, which use a variety of mechanical forces to collect particulate. A multiple cyclone is an array of a large number of small (several inch diameter) cyclones in parallel. Multiple cyclones have overall mass removal efficiencies of 70-90%. However, cyclone collection efficiencies fall off rapidly with particle size, so that control of fine particulate (PM-2.5) is limited.
[0008] Wet scrubbers are based on the collection of particles in liquid droplets, and scrubber design therefore is optimized for droplet creation. In venturi scrubbers, which are commonly used for particulate collection, the scrubbing liquid and flue gases accelerate through a converging section of duct into a narrow throat, and then pass through the throat into a diverging section. In the throat, very high gas velocity shears the scrubbing liquid into a cloud of very fine droplets, which collect particles.
[0009] The water droplets are thoroughly mixed with the dirty air, and the solid pollutants in gas air are thoroughly wetted. The wet solid pollutants, being relatively heavy, are deflected downward through the action of the baffles and reduced air velocities into the water reservoir. A constant-volume air control means interposed between the chamber and the source of polluted air, such as dirty air from an incinerator or the like, contains a primary air inlet duct and a secondary air inlet duct where the air through each duct is controlled by a damper. The dampers of the two ducts are coupled to operate complementary to each other to provide a constant air flow to the chamber for various flows of polluted air directed to the scrubber through the primary air inlet duct.
[0010] Wet Scrubber systems dealing with acid Gas/SO rely on a chemical reaction with a sorbent to remove a wide range of pollutants, including sulfur dioxide (SO 2 ), acid gases, and air toxins, from flue gases. When used to remove or “scrub” SO 2 from the flue gas, these devices are commonly called flue gas desulfurization (FGD) or scrubber systems. FGD or scrubber systems are generally classified as either “wet” or “dry”. Wet scrubbers are increasingly recognized as an important part of a multi-pollutant control program. In a wet scrubber, a liquid sorbent is sprayed into the flue gas in an absorber vessel. The gas phase or particulate pollutant comes into direct contact with a sorbent liquid and is dissolved or diffused (scrubbed) into the liquid. The liquid interface for gas and particle absorption include liquid sheets, wetted walls, bubbles and droplets.
[0011] In the wet processes, a wet slurry waste or by-product is produced. Most wet FGD systems use alkaline slurries of limestone or slaked lime as sorbents. Sulfur oxides react with the sorbent to form calcium sulfite and calcium sulfate. Uptake of the pollutant by the sorbent results in the formation of a wet solid by-product that may require additional treatment, or when oxidized, results in a gypsum by-product that can be sold. Scrubber technologies for wet scrubbing of gaseous pollutants can achieve extremely high levels of multi-pollutant control, including acid gases, SO 2 , fine particulates and heavy metals (e.g., mercury) from utility and industrial coal-fired boilers, waste-to-energy systems, and other industrial processes.
[0012] Wet scrubber technology can be applied to difficult processes such as gas absorption and particle collection, treating combustible particles, and removal of wet, sticky or corrosive particles. Wet scrubbers are used in industrial process mercury removal and to remove ionic forms of mercury from the gas stream of coal-fired power generation facilities. Wet scrubbers generally have relatively small space requirements, low capital cost, and are able to process high temperature, high acidity, and high humidity flue gas streams. Scrubber costs have continued to decrease, largely because of technical innovations. Scrubber energy requirements have also continued to decrease, helping to lower operating costs.
[0013] FGD systems are an increasingly significant part of a multi-pollutant control approach, even as the energy requirements of these systems are decreasing to where these systems now consume only about 1% of total boiler output. Where low-cost high-sulfur fuels are available, or where the required reductions are very high, scrubbing is often a viable control option. New wet scrubbers routinely achieve SO 2 removal efficiencies of 95%, with some scrubbers achieving removal efficiencies of up to 99%. Scrubbers have been used in the EPA Acid Rain Program on coal-fired boilers, which are significant sources of hydrochloric acid (HCl) and hydrofluoric acid (HF).
[0014] According to the EPA and others sources, both wet and dry scrubbers have been shown to reduce HCl emissions by 95% and more, and wet scrubbers have been shown to reduce HF emissions by more than one-third. Others have reported ranges of 87-94% removal of chlorine and 43-97% removal of fluorine by both wet and dry scrubbers. In addition, wet scrubbers also provide significant removal of arsenic, beryllium, cadmium, chromium, lead, manganese, and mercury from flue gas. Wet scrubbers can be generally grouped by geometric designs and method for gas-liquid contact. Several groupings include packed-bed, counter-flow, cross-flow, bubble-plate, open spray (single and double loop) tower, dual-flow tray, cyclonic, and venturi designs. However, there are many proprietary systems designed around specific industry needs. Design and operating parameters include scrubber geometrical shape, liquid spray or injection locations, gas residence time, gas velocities, gas and liquid temperatures, gas and liquid pressure drop, and, liquid/gas flow rate ratio.
[0015] Of prior art interest are the wet scrubbers disclosed in the Sibley et al. U.S. Pat. No. 4,609,386 and in the Clark U.S. Pat. No. 2,802,542. In these scrubbers, pollutants are removed from a gaseous or air stream by passing the polluted air through a scrubber chamber in a tortuous path, the flowing air being contacted by water sprayed into the chamber by nozzles. This action causes pollutants to be transferred from the polluted air to the water, thereby cleaning the air. Although the wet scrubbers in the patents above are highly effective in removing contaminants from the gaseous stream being discharged into the atmosphere, they do not overcome the problem of the wet scrubber being clogged by pollutants, fragments and other byproducts of the waste gas cleaning process. As a result, the nozzles become clogged which leads to a decrease in efficiency of the wet scrubber and increase in the air pollution. Furthermore, the EPA policy requires a shutdown of the system in order to remove the pollutants from the wet scrubber. This leads to frequent interruptions and an increase in production, labor, and maintenance costs.
SUMMARY OF INVENTION
[0016] Therefore, the object of the present invention is to provide a method of waste gas treatment capable of cleaning nozzles of a wet scrubber that does not require shutting down the whole system.
[0017] Another object of the present invention is to provide a wet scrubber with nozzles capable of self-cleaning when clogged with pollutant particles.
[0018] One more object of the present invention is to provide a nozzle with the quality of self-cleaning when clogged.
[0019] According to the present invention, a method of waste gas treatment with the use of a wet scrubber conventionally provides for pumping water under pressure through a pipe into at least one nozzle, passing waste gases through out of the scrubber, and spraying water in the scrubber being the nozzle to wet envelope pollutant particles in the waste gases preventing them from being discharged into atmosphere. The method additionally provides for monitoring the pressure in the pipe, and, upon exceeding by the pressure a preset value due to clogging an outlet orifice of the nozzle by the pollutants, causing the outlet orifice to increase. Due to that, the pollutant particles fall down the outlet orifice unclogging the orifice.
[0020] A wet scrubber according to the present invention is composed of a scrubber body, in which at least one nozzle is installed, a water reservoir and a pipe, through which a pump pumps water from the reservoir into the nozzle. The scrubber also comprises means monitoring water pressure in the pipe, control means controlled by the monitoring means when the water pressure exceeds a preset value due to clogging of the nozzle by pollutant particles, and means unclogging the nozzle in response to a signal from the control means.
[0021] The monitoring means may include pressure sensor/transmitter, the control means may include a control panel generating an electric signal to the nozzle upon receiving a signal from the sensor/transmitter of the water pressure in the pipe exceeding a preset value, and the unclogging means includes means enlarging an outlet orifice of the nozzle.
[0022] Those means enlarging the outlet orifice include an electromagnetic coil in the nozzle and making the nozzle with the structure where the outlet orifice is formed as an outwardly diverging conical bore in a bottom of a body of the nozzle, in which bore a coaxial conical member is installed. In this way, upon energizing the electromagnetic coil the body moves toward the coil and the distance between walls of the conical bore and the coaxial conical member defining the outlet orifice increases enlarging the outlet orifice, whereby the pollutant particles fall down the outlet orifice unclogging it. Otherwise, the body may be stationary, and the coil or a portion thereof moves toward the body with the same effect.
[0023] A self-cleaning nozzle according to the present invention is proposed to be made comprising a body defined by a top, a bottom, and walls, an inlet in the wall, through which inlet water is supplied into the nozzle, an outwardly diverging conical bore in the bottom, in which bore a coaxial conical member is installed. An outlet orifice, through which water is sprayed out of the nozzle, is defined by a distance between walls of the bore and the coaxial conical member. Also provided is an electromagnetic coil, the coaxial conical member being rigidly affixed to the coil, and the body having a spring-biased connection to the coil. Thanks to this structure, when the coil is energized, the body is attracted towards the coil compressing the spring, the distance between walls of the bore and the coaxial conical member increases, and pollutant particles clogging the outlet orifice are caused to fall down the outlet orifice unclogging the orifice. Alternatively, the body may be stationary and fixed to the scrubber, for example via lugs, and the coil structure or a portion thereof such as armature moves toward the body with the same effect.
[0024] The nozzle may also comprise a coil connector, to which the electromagnetic coil is rigidly attached, and a nozzle linker rigidly attached to the coaxial cone member and threaded into the coil connector, the coaxial cone member being preferably made an integral part of the nozzle linker.
[0025] There are at least two prongs circumferentially attached to the body, which prongs are preferably made integral parts of the body. The prongs are provided with external thread on their ends distant from the body.
[0026] The bottom of the connector is made with bores, the number of the bores corresponding to the number of the prongs. The prongs extend into the connector through the bores, with a metallic blind screw threaded onto the threaded ends of the prongs. Between the blind screen and the coil, a spring is installed so that when the coil is energized, the blind screw is attracted to the coil compressing the spring and leading the throngs and the body. Due to that, the distance between walls of the bore and the coaxial conical member increases that causes pollutant particles clogging the outlet orifice to fall down the outlet orifice unclogging the orifice. It is also possible that the body is attached to the scrubber and thus made stationary, whereas the coil structure or a portion thereof such as armature moves toward the body shifting the conical member forward and thus increasing the bore.
BRIEF DESCRIPTION OF DRAWINGS
[0027] The above-mentioned and other objects, advantages and features of the present invention will be in more detail illustrated in and will become more apparent to those skilled in the art from the ensuing specification and subjoined claims, when considered in conjunction with the accompanying drawings, in which:
[0028] [0028]FIG. 1 is a schematic diagram of a wet scrubber with self-cleaning nozzles according to the present invention;
[0029] [0029]FIG. 2 is a block diagram of a nozzle with automatic cleaning according to the present invention;
[0030] [0030]FIG. 3 is a top view of a coil connector of the nozzle according to the present invention;
[0031] [0031]FIG. 4 a is a block diagram of the nozzle according to the present invention before cleaning; and
[0032] [0032]FIG. 4 b is a block diagram of the nozzle according to the present invention after cleaning.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0033] [0033]FIG. 1 schematically illustrates the overall process of waste gas treatment based on the use of a wet scrubber according to the present invention. In a wet scrubber 10 , a pump 12 transfers water from a reservoir 14 through a pipe 16 to automatic cleaning nozzles 18 . Water is then sprayed from the nozzles 18 into waste gases passing the wet scrubber 10 , and pollutants are separated from the gases to be disposed of later.
[0034] During the cleaning process, the nozzles 18 are often clogged by the pollutants and need to be cleaned. A pressure sensor/transmitter 20 is installed to monitor water pressure in the pipe 16 . When the nozzles 18 become clogged, the pressure increases beyond a preset value, and the sensor/transmitter 20 causes a control panel 22 to start automatic cleaning the nozzles. In the absence of the pressure transmitter 20 , the control panel can be turned on manually when the nozzles 18 become clogged.
[0035] [0035]FIG. 2 illustrates in more detail an automatic cleaning nozzle according to the present invention. The nozzle 24 comprises a substantially cylindrical nozzle body 26 with walls 28 defining a chamber 30 with an inlet 32 , through which the pump 12 supplies water into the chamber 30 , and an outlet orifice 34 . The orifice 34 is made as an outwardly widening cone.
[0036] Circumferentially attached to the body 26 are four prongs 36 that are provided with external thread 38 on their ends 40 . The number of the prongs can differ from four. There can be two prongs extending circumferentially substantially enough to secure mechanical rigidity of the whole structure; there can be provided more than four of them. The prongs can be made an integral part of the nozzle body. There is also provided an electromagnetic coil 42 affixed to a cylindrical coil connector 44 . Coaxially positioned in the chamber 30 is a nozzle linker 46 with a cone flare 48 at its end 50 . The cone flare 48 is placed in the outlet orifice 34 in such a way that a ring channel 52 is formed, through which channel the water supplied to nozzle 18 via the inlet 32 is sprayed out of the nozzle.
[0037] The linker 46 passes through a bore 54 in an upper wall 56 of the nozzle body 26 , with an O-ring 58 installed in the bore 54 . Another end 60 of the linker 46 is provided with thread 62 , so as to have the linker threaded in an elevated central portion 64 of the coil connector 44 . On the other hand, the prongs 36 also extend into the connector 44 passing through four respective bores 66 in its bottom 68 . One of possible configurations of the bores 66 is shown in FIG. 3. Screwed onto the thread 38 of prongs 36 is a metallic blind screw 70 . The coil 42 is attached to the coil connector 44 by any suitable means. It can for example be glued to the connector or screwed to it. A spring 72 is placed between the coil 42 and the blind screw 70 .
[0038] Also provided in the nozzle structure is a retaining nut 74 securing the linker 46 in the connector 44 , and a fixing ring 76 with a pad 78 . The linker 46 has a stop ring 80 that, along with the fixing ring 76 and pad 78 , defines the minimal size of the ring channel 52 .
[0039] In operation, water under a preset pressure comes through the inlet 32 into the chamber 30 . From the chamber 30 , water is sprayed out through the ring channel 52 . In the course of time, the ring channel 52 of the nozzle becomes clogged with garbage, or fragments of packing, or other particles generally shown as 82 in FIG. 4 a . The clogging results in rising pressure in the pipe 16 . When the pressure exceeds a preset value, the pressure sensor/transmitter 20 turns on. The sensor/transmitter sends a signal to the control panel 22 , and the latter sends a signal to the electromagnetic coil 42 . The electromagnetic field generated by the coil causes the metallic blind screw 70 to magnetically attract to the coil 42 compressing the spring 72 . The movement of the blind screw 70 causes the nozzle body 26 rigidly connected to the blind screw 70 by prongs 36 to also move up relative to the coil connector 44 and the nozzle linker 46 rigidly connected thereto.
[0040] As can be seen in FIG. 4 b , this movement increases clearance between the outlet orifice 34 and the cone flare 48 at the end 50 of the linker 46 , and thus the size of the ring channel 52 . Due to this enlargement, all the particles 82 that clogged the nozzle fall out of it, the nozzle's capacity for work restores, the pressure returns to its normal values that disables the control panel 22 and, consequently, the coil 42 . When the signal to the coil ends, the spring 72 returns the nozzle body 26 back to its initial position shown in FIG. 4 a . Fixing ring 76 and the pad 78 preclude further movement down of the nozzle body 26 .
[0041] The use of the present invention allows lowering operational costs due to reducing time for maintenance and saving manpower expenses. Cleaning the nozzles will not require to shutdown the system.
[0042] Though the present invention has been fully described in the foregoing preferred embodiments and their alternatives, it is to be clearly understood that various modifications apparent to those skilled in the art can be made without departing from the spirit and scope of the invention. For example, as mentioned in the above, it may not be the body of the nozzle that moves toward the coil structure but rather vice versa, the effect resulting from either movement being the same. All of these modifications are therefore construed as being covered by the claims that follow.
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A self-cleaning nozzle that can be used for wet scrubbers comprises an electromagnetic coil that, when energized, causes an outlet orifice of the nozzle to enlarge so that pollutant particles clogging the nozzle fall down the orifice unclogging it. The coil is in turn controlled by a signal responsive to an increased pressure in the pipe supplying the nozzle with water, which increase is indicative of clogging the nozzle.
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BACKGROUND OF THE INVENTION
The present invention is related to reciprocating machines, and particularly to an air valve actuator for reciprocating machines. The invention is particularly adaptable for use in connection with double-acting pneumatic reciprocating diaphragm pumps and the like, wherein a pair of spaced apart diaphragm pumping chambers are interconnected by a common shaft. The invention may also find use as a pilot valve in certain industrial applications, to divert a source of pressurized fluid to either of several paths as a result of sensing a relatively small range of mechanical movement.
Reciprocating machines, and in particular reciprocating motor and pump mechanisms, utilize a valving apparatus for controlling the stroke and the reversing mechanisms to permit the reciprocating action to occur. Such machines typically use a reversing valve which is actuated by the reciprocating mechanism near the end of a stroke, to switch the driving force acting against a piston and/or diaphragm from one direction to the opposite direction. In the case of double-acting pumps, the valve reversing mechanism is utilized to exhaust the driving fluid from one side of the pump, and to admit the driving fluid into the other side of the pump. In most cases double-acting, reciprocating pumps are constructed with the active pumping elements arranged along a common axis, and with a common shaft interconnecting both elements. The common shaft therefore reciprocates in accordance with the driving elements, which may be pistons or diaphragm elements. The reversing mechanism is conveniently coupled to the reciprocable common shaft to sense the stroke position, and to actuate a reversing valve at an appropriate stroke position, to divert the pressurized driving fluid from one side of the pump to the other.
The valve actuator which causes this fluid flow diversion must be capable of positive action over a wide range of reciprocating speeds. At extremely slow reciprocating speeds the valve actuator must not be susceptible to unstable or incomplete actuation, for this could cause the pump to "stall" and cease operating. At extremely high reciprocating speeds the valve actuator must be capable of actuation very quickly in order to enable the pump to deliver the necessary and required liquid flow rates. The slow speed requirements dictate a valve actuator which has positive, snap-action operation at the changeover point. The high-speed requirement dictates that the valve actuator have relatively low mass and inertia.
It is therefore a principal object of the present invention to provide an actuator for reciprocable machines which is capable of positive and reliable actuation over a wide range of operating speeds.
It is a further object of the present invention to provide a reciprocating machine valve actuator which has a positive action at a predetermined position of the reciprocating machine, regardless of speed of operation.
It is another object of the present invention to provide an air valve actuator for a double-acting diaphragm pump which is of simple and reliable construction.
It is yet a further object of the present invention to provide an air valve actuator for a double-acting reciprocable pump which operates as an inexpensive and simple reversing valve.
The foregoing and other objects will become apparent from the specification and claims herein, and with reference to the accompanying drawings. It should be understood, however, that the detailed description and the accompanying drawings, while indicating preferred embodiments of the present invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art. Such changes and modifications should be considered to be within the scope of this invention.
SUMMARY OF THE INVENTION
A valve actuator for reciprocating machines, particularly pneumatically operated double-acting diaphragm and piston pumps, wherein the actuator mechanism is linked to the common shaft which interconnects the two pumping elements. The reciprocating motion of the shaft is coupled to an actuator link which is pivotally mounted about an axis normal to the drive shaft reciprocation direction. A detent link is also pivotally mounted about the same axis and is closely aligned with the actuator link, but otherwise unconnected to the drive shaft. The detent link carries a slide cup valve and is coupled to a spring detent mechanism which allows the detent link to be positioned in either of two predetermined positions about its pivot axis. The detent link and the actuator link have respective aligned slots therethrough, with a coil spring engaged in the slots and therefore urging the two links toward an aligned relationship. In a preferred embodiment of the invention, an actuating plug is placed inside the coil spring, the length of the actuating plug being less than the length of the slots, to thereby limit the maximum angular excursion about the pivot axis of one link with respect to the other. Because of the coupling mechanism, the actuator link swings about the pivot axis in coincidence with the drive shaft reciprocation, while the detent link is held in a fixed position by the spring detent mechanism; at a particular angular excursion of the actuator link the coil spring and/or spring plug overcomes the spring detent mechanism force and causes the detent link to follow the actuator link. The detent link rapidly moves to its second detent position, sliding the cup valve in coincidence, and the cup valve redirects the flow of pressurized fluid from one side of the pump to the other, while at the same time exhausting the previously pressurized side of the pump to an exhaust port.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will become more fully understood and apparent from the detailed description of the preferred embodiment provided herein, and with reference to the accompanying drawings, which are provided by way of illustration and not by way of limitation of the scope of the present invention.
FIG. 1 shows an isometric view of a double-acting diaphragm pump incorporating the present invention;
FIG. 2 shows a cross-section view taken along the lines 2--2 of FIG. 1;
FIG. 3 shows a cross-sectional view of the pump and invention taken lines 3--3 of FIG. 1;
FIGS. 4A-4D show the present invention in four different operational positions.
FIG. 5 shows an expanded view of a portion of an alternative form of the actuator; and
FIG. 6 shows one form of mechanical link between the actuator and drive shaft.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring first to FIG. 1, there is shown an isometric view of a double-acting diaphragm pump 10. Pump 10 has a pair of aligned pumping chambers 12, 13, each of which contain a diaphragm, and wherein the diaphragms are interconnected by a common shaft. Intermediate pumping chambers 12, 13 is an actuator housing 14 which has a removable cover plate 26. Pumping chambers 12 and 13 have a pair of liquid delivery passages 16, 17 for receiving liquid and delivering liquid therefrom at an elevated pressure and flow delivery rate. Suitable check valves are utilized with chambers 12 and 13 to control the direction of flow into and out of the pumping chambers In the embodiment shown in FIG. 2, passage 16 is an intake passage and passage 17 is a delivery passage. Actuator housing 14 has a pressurized air intake line 20 coupled thereto, and an air exhaust line 21 extending therefrom. The pressurized air provided by line 20 serves as the driving energy source for the operating features of pump 10.
Referring next to FIG. 2, pump 10 is shown in cross-section view, taken along the lines 2--2 of FIG. 3. A cavity 24 is formed in actuator housing 14 to provide space for receiving the valve actuator mechanism, to be hereinafter described. A passage 20a is formed into cavity 24, and connects to pressurized air intake 20. An exhaust port 21a also opens into cavity 24, and connects to air exhaust 21. A passage 22 is coupled between pumping chamber 12 and cavity 24, opening into cavity 24 via a port 28. A passage 23 is coupled between pumping chamber 13 and cavity 24, opening into cavity 24 via port 29. A common shaft 30 interconnects between the respective diaphragms in pumping chambers 12 and 13, and passes through cavity 24. A center groove 31 in shaft 30 serves to assist in performing the driving linkage between shaft 30 and the valve actuator, to be hereinafter described. A pivot hole 32 is formed in cavity 24, for accepting the valve actuator pivot pin to be hereinafter described. A diaphragm 56 is clamped by a diaphragm holding mechanism 56a in chamber 12. Similarly, a diaphragm 57 is clamped by a diaphragm holding mechanism 57a in chamber 13.
FIG. 3 shows a view taken along the lines 3--3 of FIG. 1, with the valve actuator mechanism 40 in operational relationship. FIG. 3 also shows cover 26 secured into operable position on actuator housing 14. Air intake passage 20 and air exhaust passage 21 pass through housing 14 to open into the chamber created by cavity 24. Valve actuator mechanism 40 is pivotally attached to housing 14 by means of a pivot pin 34. Pivot pin 34 is preferably affixed to a detent link 44, whereas an actuator link 42 is freely movable about pivot pin 34. A coil spring 50 is seated within slots 35, 36 in detent link 44 and actuator link 42, for purposes to be hereinafter described (FIGS. 4A-4D). Detent link 44 has a cup valve 46 affixed against its underside surface, and has two detent depressions in its upper surface. A detent ball 48 is urged by a compression spring 49 into contact against the upper surface of detent link 44.
FIG. 6 shows a yoke 15 which is used as the mechanical linkage between the shaft groove 31 and actuator link 42. Yoke 15 has a curved lower surface 25 which is sized for engagement against shaft groove 31. The upper portion of yoke 15 forms a shoulder 27 which may be inserted through an opening 27a in actuator link 42. By the use of yoke 15, the reciprocable motion of shaft 30 is transferred to actuator link 42, thereby causing actuator link 42 to pivot in an oscillatory fashion about pin 34. Shoulder 27 does not engage detent link 44, but is engaged only through an opening in actuator link 42.
FIGS. 4A through 4D show bottom views of valve actuator 40 in each of four operational positions. FIG. 4A shows actuator link 42 and detent link 44 in alignment, wherein each are pivoted to one extreme pivot position within cavity 24. In this position, detent link 44 contacts the outside wall surface 24a of cavity 24. This position represents the rightmost position of the piston shaft 30, as viewed in FIGS. 4A-4D, and also corresponds to the changeover when piston shaft 30 begins moving leftward from its rightmost position, as indicated by the arrow in FIG. 4A. In the actuator link 42 position shown in FIG. 4A, cup valve 46 provides a flow communication path between passage 28 and exhaust port 21a. Passage 29 is exposed to the interior of the chamber formed by cavity 24, and is therefore exposed to the source of pressurized air which enters via port 20. The pressurized air flow into port 29 flows to pumping chamber 13, thereby forcing the diaphragm in chamber 13 outwardly. By contrast, the air in pumping chamber 12 passes through passage 28 to exhaust port 21, and is exhausted to the atmosphere; i.e., pumping chamber 12 becomes depressurized while pumping chamber 13 becomes pressurized.
FIG. 4B shows valve actuator 40 in a further position, wherein actuator link 42 has been pivoted leftwardly, viewed from the bottom, a predetermined amount, as a result of following the leftward movement of piston shaft 30. Detent link 44 remains in its rightmost position, under the influence of the spring detent mechanism 47, which tends to hold it in this position. As a result, coil spring 50 becomes compressed by the relative misalignment of the slots 35, 36 in actuator link 42 and detent link 44. The spring force developed by the compression of spring 50 is applied against detent link 44 in increasing amounts as actuator link 42 pivots leftwardly. It is to be noted that, in the position shown in FIG. 4B, port 29 remains exposed to the pressurized air within the chamber formed by cavity 24, and port 28 remains coupled in flow relationship to exhaust port 21.
FIG. 4C shows the respective positions of the actuator link and detent link after the spring force of coil spring 50 has increased sufficiently to cause detent link 44 to release from its detent position, and to move leftwardly into its second detent position, as shown. In this position, detent link 44 engages the interior wall 24a of cavity 24, and cup valve 46 provides a flow path from passage 29 to exhaust port 21. Passage 28 becomes exposed to the pressurized air within cavity 24, and conveys this pressurized air into chamber 12. This causes the diaphragm in chamber 12 to move outwardly, thereby causing shaft 30 to move rightwardly, as shown by the arrow in FIG. 4C. Actuator link 42 continues to move with shaft 30, and begins pivoting rightwardly in accordance with the movement of shaft 30.
FIG. 4D shows the positions of the actuator link and detent link after a predetermined rightward movement of shaft 30, and pivoting motion of actuator link 42. In this position, actuator link 42 has pivoted about pin 34 a predetermined angular amount. Detent link 44 remains in its leftmost position under the influence of the detent spring arrangement 47, but the compression force of coil spring 50 presents an increasing rightward force against detent link 44. Upon sufficient rightward movement of actuator link 42, the spring force of coil spring 50 is sufficiently large to overcome the spring detent force acting to hold detent link 44 in the position shown in FIG. 4D, and detent link 44 will then suddenly move rightwardly to its first detent position, as is shown in FIG. 4A. This completes the cycle of actuation provided by valve actuator 40 under all conditions of operation. It is important to note that detent link 44 will occupy either of two detent positions, depending upon the total spring forces acting against it. When the compression force of coil spring 50 exceeds the spring detent force acting upon detent link 44, the spring detent force is overcome and detent link 44 is rapidly forced into its other detent position.
FIG. 5 shows an alternate construction wherein a more positive and predetermined switchover may be provided with valve actuator 40 In this example a plug 52 is loosely inserted within coil spring 50, and is constrained therein by coil spring 50. Plug 52 is freely movable along the axis of coil spring 50 within slots 35, 36, when the actuator links 42, 44 are in alignment. As the actuator links 42, 44 become misaligned because of the pivoting motion of actuator link 42, the path of free movement of plug 52 gradually becomes reduced. At some degree of misalignment plug 52 becomes engaged between the respective side walls of slots 35, 36, and further pivotal motion of actuator link 42 forces a corresponding pivotal motion of detent link 44. This motion overcomes the detent spring force and causes detent link 44 to immediately snap into its other detent position. The advantage of the alternative construction of FIG. 5 is that it does provide a positive movement of detent link 44 at a predictable and predetermined pivotal position of actuator link 42. It removes any uncertainties in the balance of spring forces which act upon detent link 44, and in particular eliminates any uncertainties caused by spring force characteristics which may change over time and use. The alternative construction of FIG. 5 is therefore preferable for providing a valve actuator having precise action over an extended period of use.
FIG. 5 also shows an alternative with respect to the actuation mechanism of actuator link 42. This construction does not rely on the use of a yoke 15 to impart pivotal motion to actuator link 42 as previously described herein, but utilizes another form of actuation. It is particularly useful in some reciprocating mechanisms, wherein the reciprocable motion of a piston or diaphragm may be tracked by a movable pair of rods 54, 55. Rods 54, 55 may be aligned so as to move in correspondence with the reciprocation of a piston or other driving member, and also to come into contact with actuator link 42 during at least a portion of the reciprocation stroke In this example, rods 54, 55 move laterally into contact with actuator link 42, thereby causing actuator link 42 to pivot about its pivot pin 34, to achieve the same relative pivotal motion as described earlier. Of course, in this construction the use of a yoke 15 or similar construction is unnecessary. However, it is preferable in this construction to form the actuator link 42 with partially raised lips 42a, 42b along its respective edges. This raised lip construction provides a more reliable contact surface for rods 54, 55.
In operation, the liquid inlet and outlet hoses are suitably connected to a source and destination of the liquid to be pumped, and pressurized air is coupled to pressurized air intake 20. The source of pressurized air is typically fed through a valve and regulator mechanism so that the degree of pressurization can be controlled. As soon as pressurized air is admitted into the actuator housing it immediately passes into one of the pumping chambers 12, 13, depending upon the initial position of valve actuator 40. This causes the diaphragm in the pressurized chamber to move outwardly, thereby moving the connecting shaft in the same direction and causing the valve actuator to operate correspondingly. At a predetermined shaft position the valve actuator toggles to redirect the flow of pressurized air to the other pumping chamber, and to relieve the first pumping chamber of its pressurized air. This causes the shaft to move in the opposite direction to continue the cycling of the pump. If the pressurized air is increased, the reciprocating action of the pump will correspondingly increase, and if the pressurized air is decreased the reciprocating action of the pump will correspondingly decrease.
The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and it is therefore desired that the present embodiment be considered in all respects as illustrative and not restrictive, reference being made to the appended claims rather than to the foregoing description to indicate the scope of the invention.
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An air control valve for directing air flow in a double-acting reciprocable motor, where the valve has a first link which is pivotally connected at one end to the motor and mechanically coupled along its length to a reciprocable motor member; a second link pivotally connected to the same point as the first link, and having an over-center spring detent mechanism to position it in either of two pivot positions; both of the links having alignable transverse slots, with a compression coil spring engaged in both slots; and a slide valve member attached to the second link and pivotally movable therewith, to direct the air flow into either of the double-acting motor drive members, the air valve toggling to its second position near the end of the motor drive stroke to cause the motor to reciprocate in the other direction.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] Not applicable.
BACKGROUND OF THE INVENTION
[0002] The invention relates to improved drilling fluid additions which comprise fine particles of crosslinked elastomer. The elastomer acts as a plugging agent thereby preventing loss of the drilling fluid to a porous formation. A method for preventing loss of drilling fluids is also provided.
[0003] Drilling fluids, or drilling muds as they are sometimes called, are slurries used in the drilling of wells in the earth for the purpose of recovering hydrocarbons and other fluid materials. Drilling fluids have a number of functions, the most important of which are: lubricating the drilling tool and drill pipe which carries the tool, removing formation cuttings from the well, counterbalancing formation pressures to prevent the inflow of gas, oil or water from permeable rocks which may be encountered at various levels as drilling continues, and holding the cuttings in suspension in the event of a shutdown in the drilling and pumping of the drilling fluid.
[0004] For a drilling fluid to perform these functions and allow drilling to continue, the drilling fluid must stay in the borehole. Frequently, undesirable formation conditions are encountered in which substantial amounts or, in some cases, practically all of the drilling fluid may be lost to the formation. Drilling fluid can leave the borehole through large or small fissures or fractures in the formation or through a highly porous rock matrix surrounding the borehole.
[0005] Most wells are drilled with the intent of forming a filter cake of varying thickness on the sides of the borehole. The primary purpose of the filter cake is to reduce the large losses of drilling fluid to the surrounding formation. Unfortunately, formation conditions are frequently encountered which may result in unacceptable losses of drilling fluid to the surrounding formation despite the type of drilling fluid employed and filter cake created.
[0006] A variety of different substances are now pumped down well bores in attempts to reduce the large losses of drilling fluid to fractures and the like in the surrounding formation. Different forms of cellulose are the preferred materials employed. Some substances which have been pumped into well bores to control lost circulation are: almond hulls, walnut hulls, bagasse, dried tumbleweed, paper, coarse and fine mica, and even pieces of rubber tires. These and other prior art additives are described in U.S. Pat. No. 4,498,995.
[0007] Another process that is employed to close off large lost circulation problems is referred to in the art as gunk squeeze. In the gunk squeeze process, a quantity of a powdered bentonite is mixed in diesel oil and pumped down the well bore. Water injection follows the bentonite and diesel oil. If mixed well, the water and bentonite will harden to form a gunky semi-solid mess, which will reduce lost circulation. Problems frequently occur in trying to adequately mix the bentonite and water in the well. The bentonite must also be kept dry until it reaches the desired point in the well. This method is disclosed in U.S. Pat. No. 3,082,823.
[0008] Many of the methods devised to control lost circulation involve the use of a water expandable clay such as bentonite which may be mixed with another ingredient to form a viscous paste or cement. U.S. Pat. No. 2,890,169 discloses a lost circulation fluid made by forming a slurry of bentonite and cement in oil. The slurry is mixed with a surfactant and water to form a composition comprising a water-in-oil emulsion having bentonite and cement dispersed in the continuous oil phase. As this composition is pumped down the well bore, the oil expands and flocculates the bentonite which, under the right conditions, forms a filter cake on the well bore surface in the lost circulation area. Hopefully, the filter cake will break the emulsion causing the emulsified water to react with the cement to form a solid coating on the filter cake. But such a complex process can easily go wrong.
[0009] U.S. Pat. No. 3,448,800 discloses another lost circulation method wherein a water soluble polymer is slurried in a nonaqueous medium and injected into a well. An aqueous slurry of a mineral material such as barite, cement or plaster of paris is subsequently injected into the well to mix with the first slurry to form a cement-like plug in the well bore.
[0010] U.S. Pat. No. 4,261,422 describes the use of an expandable clay such as bentonite or montmorillonite which is dispersed in a liquid hydrocarbon for injection into the well. After injection, the bentonite or montmorillonite will expand upon contact with water in the formation. Thus, it is hoped that the expanding clay will close off water producing intervals but not harm oil producing intervals.
[0011] A similar method is disclosed in U.S. Pat. No. 3,078,920 which uses a solution of polymerized methacrylate dissolved in a nonaqueous solvent such as acetic acid, acetic anhydride, propionic acid and liquid aliphatic ketones such as acetone and methyl-ethyl ketone. The methacrylate will expand upon contact with formation water in the water-producing intervals of the well.
[0012] It has also been proposed to mix bentonite with water in the presence of a water-soluble polymer which will flocculate and congeal the clay to form a much stronger and stiffer cement-like plug than will form if bentonite is mixed with water. U.S. Pat. No. 3,909,421 discloses such a fluid made by blending a dry powdered polyacrylamide with bentonite followed by mixing the powder blend with water. U.S. Pat. No. 4,128,528 claims a powdered bentonite/polyacrylamide thickening composition prepared by mixing a water-in-oil emulsion with bentonite to form a powdered composition which rapidly becomes a viscous stiff material when mixed with water. U.S. Pat. Nos. 4,503,170; 4,475,594; 4,445,576; 4,442,241 and 4,391,925 teach the use of a water expandable clay dispersed in the oily phase of a water-in-oil emulsion containing a surfactant to stabilize the emulsion and a polymer dispersed in the aqueous phase. When the emulsion is sheared, it breaks and a bentonite paste is formed which hardens into a cement-like plug. The patent discloses the use of such polymers as polyacrylamide, polyethylene oxide and copolymers of acrylamide and acrylic or methacrylic acid.
[0013] A group of oil absorbent polymers is disclosed in U.S. Pat. Nos. 4,191,813; 4,263,407; 4,384,095 and 4,427,793. U.S. Pat. No. 4,191,813 discloses lightly crosslinked copolymers containing at least 40% by weight of vinylbenzyl chloride, the balance of monomers, if any, comprising a major portion of aromatic monomers, with the copolymer being crosslinked in a swollen state by a Lewis acid catalyst. The preferred comonomers are one or more of styrene, divinylbenzene and acrylonitrile. U.S. Pat. No. 4,263,407 discloses similar copolymers wherein the copolymer is post-crosslinked in a swollen state in the presence of a Friedel-Crafts catalyst with a crosslinker selected from a polyfunctional alkylating or acylating agent and a sulfur halide.
[0014] Another group of highly hydrocarbon absorbent copolymers is disclosed in U.S. Pat. Nos. 4,384,095 and 4,427,793. They describe a crosslinked linear addition copolymer which contains repeating units of vinylbenzyl alcohol and at least one other alpha, beta-monoethylenically unsaturated monomer different from vinylbenzyl alcohol, wherein the vinylbenzyl alcohol units comprise about 0.5% to about 20% by weight of the linear polymer. The preferred comonomers are styrene, methylmethacrylate, vinyltoluene and vinylpyridine. The copolymers disclosed in all four of these patents absorb from two to ten times their weight in hydrocarbons and may swell up to ten times their original volume.
[0015] Oleophilic polymers for separating oil from water which show significant swelling in volume upon absorption of oil are described in U.S. Pat. No. 4,172,031. These polymers include polymers of styrenes and substituted styrenes, polyvinyl chloride copolymers of vinylchloride such as a copolymer of 60 wt % vinylchloride and 40 wt % vinylacetate, polymers and copolymers of vinylidene chloride and acrylonitrile, and acrylic polymers such as polymers of methylmethacrylate and ethylacrylate, styrene and divinylbenzene copolymers and alkyl styrene polymers and copolymers. The reference discloses that these polymers show significant swelling in volume upon absorption of oil.
[0016] U.S. Pat. No. 4,633,950 discloses the use of oil swelling polymers to reduce lost circulation in drilling fluids. In this patent, the polymers are introduced in an aqueous solution to prevent absorption of the hydrocarbon fluid until the polymers reach the well head.
[0017] While the above inventions purport to be effective in reducing loss of drilling fluids, there continues to be a need for effective and inexpensive additives for well bore fluids which can prevent or stop the loss of the fluids into the subterranean formation.
BRIEF SUMMARY OF THE INVENTION
[0018] The present invention is directed to a system and method which <<<begin typing here>>>.
[0019] The invention relates to an improved additive for a drilling fluid which significantly reduces the loss of fluid to the surrounding subterranean structure while maintaining the lubricity of the drilling fluid. The novel additive comprises finely ground elastomer particles.
[0020] Loss of drilling fluid occurs when drilling fluid seeps into the subterranean formation through holes, fractures or fissures in the formation. The region in the well where this occurs is referred to as the lost circulation zone. When elastomer particles are added to a drilling fluid, they form a seal in the lost circulation zone by expanding in size to seal the fractures or fissures. This prevents further loss of drilling fluid into the formation.
[0021] In contrast to other elastomer based additives discussed above, the present system uses fine elastomer particles which are easily pumped into the well but are capable of swelling to about 40% to about 140% more than their original size when exposed to hydrocarbon fluids. Their ability to swell makes the elastomer particles extremely effective at preventing loss of drilling fluid into the subterranean formation. When the elastomer particles are used with hydrocarbon-based drilling fluids or with a hydrocarbon additive, particles gradually expand, allowing the material to be easily pumped before significant expansion of the particles occurs. That most of the swelling occurs after the elastomer particles are in the desired location in the well eliminates the need for protective coatings or an aqueous pill to prevent swelling of the polymer until it has reached the desired region in the well.
[0022] Another advantage of the elastomer particles is their very low density as compared to conventional materials used to prevent fluid loss. The low density of the elastomer particles allows them to be used in higher amounts than conventional fluid loss materials.
[0023] The fluid loss prevention system of the invention require no additional additives other than those normally encountered in drilling fluid such as diesel, oil, other hydrocarbon fluid and water. The elastomer particles are easily handled and present little if any industrial hazards. Moreover, since the preferred source of the fluid loss agents of the invention are prepared from recycled tires, the invention presents a way to effective use the old tire materials rather than allowing them to collect to form hazardous waste sites.
[0024] The invention also relates to a method for reducing drilling fluid loss by adding finely ground elastomer particles to a drilling fluid in an amount sufficient to block the flow of fluid into the subterranean formation.
[0025] The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention. It should be appreciated that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized that such equivalent constructions do not depart from the invention as set forth in the appended claims. The novel features which are believed to be characteristic of the invention, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures. It is to be expressly understood, however, that each of the figures is provided for the purpose of illustration and description only and is not intended as a definition of the limits of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0026] The drilling fluid additive of the present invention comprise particles of elastomers which exhibit swelling when contacted with hydrocarbon fluids, yet do not dissolve in hydrocarbon fluids. This can be achieved by using crosslinked elastomers which swell but do not dissolve in the presence of a hydrocarbon fluid. The swelling elastomers are such that little, if any, swelling occurs until the polymer has reached the lost circulation zone in the well to be sealed. This is accomplished without resort to coatings on the polymer or suspending the polymer with aqueous pill.
[0027] The preferred elastomer used in the practice of this invention is crumb rubber. Crumb rubber generally comprises rubber derived from recycled tires or scrap material from the manufacture of tires. Crumb rubber particles are generally of about ⅜-inch or less in size. In the practice of the invention, the crumb rubber should have a mixture of particle sizes ranging of from about 1 to about 400 microns, preferably about 20 to about 400 microns. In the preferred embodiment, the material should include particles of varying diameters within the range stated above.
[0028] In an alternative embodiment, the elastomer can be slightly larger, in the range of from greater than or about 400 to about 4000 microns. In a preferred embodiment, the additive can include particles of up to about 2000 microns (10 mesh) and more preferably up to about 1000 (18 mesh) microns. Mixtures of particle sizes within the ranges can also be used. For example, the additive can include particles of about 425 microns, (48 mesh), about 1000 microns, (18 mesh) and about 2000 microns (10 mesh).
[0029] Crumb rubber can be prepared several different ways. In the first method, whole tires are cryogenically frozen and then shattered in a hammer mill to break down the tire into the desired particle sizes and to remove the steel and fibers from the tire. A second method involves physically tearing the tire apart and removing the unwanted steel and fibers. In this process, the tire is continuously milled until the desired particle sizes are obtained. Another source of crumb rubber is the bushings that remain as the tire is manufactured or remanufactured.
[0030] One key feature of crumb rubber that makes it useful in the practice of the invention is its ability to expand up to about 140% of its original size when exposed to hydrocarbon fluids and temperatures. As shown in the examples below, when the elastomer particles are exposed to hydrocarbon fluids and temperatures typically encountered in a well (200° F. to 300° F.) the particles expand to over 140% of their original size. The amount of expansion is dependent upon the hydrocarbon used and the temperature in the well.
[0031] The expansion of the elastomer is not immediate, often taking several hours before a significant increase is seen. The delay in expansion of the crumb rubber means that the crumb rubber can be easily pumped down a well bore without resort to coatings or the use of an aqueous pill. The crumb rubber can then flow into the pores and cracks. Once in the cracks and pores, the crumb rubber will expand to fill the cracks and pores without dissolving into the drilling fluid. Thus, while crumb rubber is the preferred elastomer in the practice of the invention, any elastomer which exhibits the same swelling and solubility characteristics as crumb rubber may be used.
[0032] Another feature of the present invention is the relatively low density of the elastomer particles, relative to the fluid. This allows a higher additive loading without adversely affecting the properties of the drilling fluid. For example, the elastomers of the invention can be used in amounts up to about 100 lbs. per barrel (ppb) whereas conventional fluid loss additives can be used in amounts ranging from about 5 to about 20 lbs. per barrel. The ability to use higher additive loadings means that more of the elastomer particles are present in the fluid to fill and plug the openings into the subterranean formation.
[0033] This last feature is particularly important in deepwater operations where the drilling fluids used require a narrow density range. Typically the fluids used in these applications have a density of from about 9.5 to about 10.5 pounds per gallon (ppg). The elastomer particles of the invention have a density of from about 8.5 to about 10.5 ppg. Thus, the addition of the additives of the invention do not adversely affect the density drilling muds.
[0034] Illustrative hydrocarbon fluids useful in this invention include crude oil, diesel oil, kerosene, mineral oil, gasoline, naptha, toluene, ethylenedichloride and mixtures thereof. In addition, synthetic oils such as those derived from olefins, linear α-olefins, poly α-olefins, internal esters and ethers may be used. Because of economics, availability at any drilling site and performance, diesel oil is most preferred. Synthetic oils, however, are preferred where environmental impact is a concern.
[0035] The drilling fluid additives of the present invention can be used in both hydrocarbon based and aqueous or water based drilling fluids. If polymer expansion is needed in an aqueous system, a hydrocarbon fluid must be added to the elastomer particles to achieve the desired expansion. It has been observed, however, that improved fluid loss can be achieved in aqueous drilling fluids without adding a hydrocarbon fluid. The improved fluid loss reduction is achieved by the ability to use higher amounts of particles.
[0036] One method for practicing this invention involves the injection of a discrete pill of drilling fluid containing the drilling fluid additives of the invention in a sufficient amount to seal off the lost circulation zone. This pill is then forced down to the lost circulation zone. The elastomer particles then fill the holes and fractures preventing loss of the fluid. Depending upon the polymer and the composition of the drilling fluid, about two to about 250 pounds of polymer per barrel of fluid can be placed in the pill. Methods for introducing the pill containing the drilling fluid additive of the invention are well known to those in the art.
[0037] Other matter may be added to the pill to enhance the sealing properties of the fluid. For example, cellulose fiber from plant matter such as peanut shells, sugar cane husks or bagasse, almond shells, walnut shells, dried tumbleweed and paper, may be added to the pill. Bridging materials such as calcium carbonate may also be added. Coarse and fine mica can also be used.
[0038] To help maintain the seal established by the polymer containing pill and to prevent loss to new fractures, the polymer of the invention can be continuously added to the drilling fluid. In these cases, the polymer should be added at a rate of 100 to 250 pounds per hour to the drilling fluid.
EXAMPLES
Example 1
[0039] In this example, samples of crumb rubber were exposed to various hydrocarbon fluids to measure the degree of expansion over time. In each experiment, 20 mls of the base fluid were added to a 150 mm test tube. To this was added 2.29 gms of crumb rubber. The tube was then shaken to set the crumb rubber. The total height of the fluid and crumb rubber was measured at 108 mm. The height of the rubber in each sample was 33 mm. The hydrocarbon fluids used in these tests were two commercial internal olefin fluids, a linear α-olefin fluid and #2 diesel.
[0040] The test tube was then placed in a Baroid 500 ml static-aging cell which was then pressurized to 300 psi with nitrogen. The cell was then placed in an oven at the temperatures noted in the tables and static-aged for three days. A duplicate sample was static-aged for seven days.
[0041] After static-aging, the test tubes were removed from the test cells and the height of the rubber was measured. The amount of expansion was calculated using the formula (“height after aging/33)−1.” The results are reported in Tables 1 and 2.
TABLE 1 Solubility and Percent Expansion of NER PipeRubber after three day tests Temperature IO Base #1 LAO Base IO Base #2 #2 Diesel 200° F. 103% 97% 127% 158% 250° F. 109% 109% 97% 152% 300° F. 112%* 112%* 97% 158%* *Denotes partial solubility of PipeRubber in Base Fluid.
[0042]
TABLE 2
Solubility and Percent Expansion of NER PipeRubber
after seven day tests
Temperature
IO Base #1
LAO Base
IO Base #2
#2 Diesel
200° F.
82%
97%
103%
106%
250° F.
112%
118%
118%
158%
300° F.
127%
97%*
112%*
103%*
*Denotes partial solubility of PipeRubber in Base Fluid.
Example 2
[0043] In this example, a well was experiencing significant loss of drilling fluid. Traditional loss prevention treatments with agents such as calcium carbonate, fiber and graphite materials proved ineffective in reducing or stopping the loss.
[0044] A combination of 30 pound per barrel of crumb rubber with 20 pounds per barrel of fiber were added to the drilling fluid. After the initial loading of crumb rubber and fiber, a maintenance load of 250 pounds of crumb rubber and 150 pounds of fiber per hour of pumping were used. The result was little or no additional loss of drilling fluid during the rest of the drilling process.
Example 3
[0045] In this example, a deepwater drilling rig was experiencing fluid losses of from 50 to 60 barrels an hour. Attempts to use conventional fluid loss control agents proved unsuccessful.
[0046] Two 50-barrel pills of fluid were prepared, each containing 15 pounds per barrel of crumb rubber were pumped into the well. After these pills were pumped into the well, the rate of fluid loss dropped to between 10 and 20 barrels an hour.
[0047] Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the invention as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one will readily appreciate from the disclosure, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.
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The invention is a novel drilling fluid additive comprising particles of elastomer which are capable of swelling upon contact with a hydrocarbon fluid. The swelling of the elastomer is gradual, allowing the elastomer to reach the lost circulation zone before significant swelling occurs. Once in the lost circulation zone, the polymer expands sealing off the lost circulation zone. A method for preventing drilling fluid loss is also provided.
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TECHNICAL FIELD
The present invention relates to CMOS image sensors, and more particularly, to a CMOS image sensor having a pixel architecture that allows for sharing of output transistors during readout.
BACKGROUND
Integrated circuit technology has revolutionized various fields, including computers, control systems, telecommunications, and imaging. In the field of imaging, complimentary metal oxide semiconductor (CMOS) active pixel image sensors have made considerable inroads into applications served by charge coupled imaging devices. As noted in U.S. Pat. No. 5,625,210 to Lee et al. (“the '210 patent”), an active pixel sensor refers to an electronic image sensor with active devices, such as transistors, that are associated with each pixel. The active pixel sensor has the advantage of being able to incorporate both signal processing and sensing circuitry within the same integrated circuit because of the CMOS manufacturing techniques.
One common design for an active pixel is the basic, three-transistor CMOS active pixel which contains a photodiode; a reset transistor for resetting the photodiode voltage, a source follower for amplification, and a row select transistor for buffering the photodiode voltage onto a vertical-column bus. However, the three-transistor pixel is lacking in its ability to suppress noise due to the reset operation, referred to as kTC noise. Further, the three-transistor pixel does not have good response to blue light.
Another popular active pixel sensor structure consists of four transistors and a pinned photodiode. The pinned photodiode has gained favor for its ability to have good color response for blue light, as well as advantages in dark current density and image lag. Reduction in dark current is accomplished by “pinning” the diode surface potential to the Pwell or Psubstrate (GND) through a P+ region. Because of the particular characteristics of pinned photodiodes, it is necessary to incorporate a transfer transistor that is not required in the three-transistor design discussed above.
Still, one disadvantage of the pinned photodiode is that it requires four transistors for each pixel. Thus, a one-megapixel image sensor would require 4 million transistors simply for the imaging array. As higher resolution image sensors become popular, coupled with the need for higher integration densities, it is desirable to implement the pinned photodiode pixel while limiting the number of required transistors.
BRIEF DESCRIPTION OF THE DRAWINGS
The foregoing aspects and many of the attendant advantages of the invention will become more readily appreciated as the same become better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein:
FIG. 1 is a schematic diagram of a prior art active pixel.
FIG. 2 is a cross section view of the prior art active pixel of FIG. 1 .
FIG. 3 is a schematic diagram of a portion of a column of a prior art image sensor array.
FIG. 4 is a schematic diagram of a portion of a column of an imaging array formed in accordance with the present invention.
FIG. 5 is a block diagram of a CMOS image sensor formed in accordance with the present invention.
DETAILED DESCRIPTION
The present invention relates to an active pixel design using a pinned photodiode that requires fewer than an average of four transistors per active pixel. In the following description, numerous specific details are provided to provide a thorough understanding of the embodiments of the invention. One skilled in the relevant art will recognize, however, that the invention can be practiced without one or more of the specific details, or with other methods, components, etc. In other instances, well-known structures or operations are not shown or described in detail to avoid obscuring aspects of various embodiments of the invention.
Reference throughout the specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout the specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.
FIGS. 1 and 2 show a prior art active pixel 101 with pinned photodiode 103 . The pinned photodiode 103 is typically an N-well formed in a P-type substrate. A P+ region is formed atop of the N-well. A transfer gate (also referred to as a transfer transistor) controls the transfer of the signal from the pinned photodiode 103 to an output node 107 . The output node 107 is connected to the gate of a source-follower transistor 109 (also referred to as a drive or output transistor). This results in the signal on the output node 107 being amplified and placed onto the column line out 111 . A row select transistor (SEL) is used to select the particular pixel to be read out on the column line out 111 . The row select transistor is controlled by a row select line. Further, a reset transistor 113 is used to deplete the signal from the sensing node. In order to reduce the leakage current from the silicon surface and kTC noise, the photodiode is typically provided with a pinning P+ surface shield layer at the silicon surface and is completely depleted.
FIG. 3 illustrates a portion of a column from a sensor array using pinned photodiode pixels. In the illustration, column one of the array is shown and the first three rows of the array are shown. As seen, a column line out 111 carries the signals from the rows to readout circuitry (not shown). The row select (SEL) transistors for each pixel are selectively activated one at a time to read out the pixel signals. As seen, for three pixels, twelve transistors are required. Extrapolated out, a one megapixel array would require four million transistors for the imaging array.
The present invention can reduce the amount of transistors required to implement a pinned photodiode sensor array. This reduction is made possible by sharing the source follower transistor 109 and reset transistor between two or more adjacent rows of pixels. This sharing of transistors will reduce greatly the overall number of transistors required to implement a pinned photodiode image sensor.
Specifically, turning to FIG. 4 , a portion of an imaging array is shown. This specific portion shows a single column (Column 1 ) and four rows. In contrast to the prior art, note that adjacent pixels in rows 1 and 2 share a source follower and a reset transistor. Similarly, adjacent pixels in rows 3 and 4 share a source follower and reset transistor. Further, note that in accordance with the present invention there is no row select transistor needed. Instead, the drain of the source follower transistor is connected directly to the column line out 111 . Thus, the total number of transistors required for these four pixels is eight. Therefore, on average, each pixel requires only two transistors. This is a significant savings from the four transistors for each pixel in the prior art of FIG. 3 .
Further, while it is shown that two pixels share a common reset transistor and source follower transistor, this can be increased to perhaps three or even four pixels in a column for greater transistor savings. However, in the embodiment shown in FIG. 4 , two pixels in adjacent rows share the reset transistor and source follower transistor.
Moreover, the reset transistor has its upper connection (the drain) connected to either a low voltage V ss or a high voltage reference V ref . As will be seen below, the reset transistor will place either V ss or V ref onto node A as appropriate for the operation of the present invention. The actual switching between V ss or V ref can be easily done using a simple control switch (not shown) as is apparent to those of ordinary skill in the art.
The output node 107 (also referred to Node A) thus is shared between two pixels. The operation of the present invention is explained as follows. When the signal from row 1 is to be read out, the reset transistor is turned on to allow high voltage reference V ref to be placed on node A. The other node A's for all of the other rows are placed at voltage V ss through their respective reset transistors. Thus, only node A associated with the row to be read is at high voltage, while all of the other node A's for the other rows are at low voltage.
Next, the reset transistor for the row to be read is turned off and the transfer gate for the row is turned on. The accumulated charge from the photodiode is then transferred to Node A and, along with the high voltage already placed on node A, will modulate the source follower transistor. The transfer gate for the adjacent row pixel (row 2 ) is off at this time. Thus, the signal produced by the photodiode of the pixel in row 1 modifies the high voltage “base point” and is then amplified by the source follower and the signal is provided onto the column line output 111 .
Once this has been done, the reset transistor drain voltage is switched over to low and the reset transistor is turned on. This resets node A to the low reference voltage, such as V ss .
For reading of the next row (Row 2 ), the procedure is repeated where the reset transistor places a high voltage onto Node A and then turning on the transfer gate for row 2 is turned on and the signal from the photodiode of the row 2 pixel is transferred to the output node 107 to mix with the high voltage.
At this time, the transfer gate for the row 1 pixel is turned off. The signal on the output node 107 from the row 2 pixel is then amplified by the source follower and the signal is output via the column line out 111 . Note that during the read out of rows 1 and 2 , Node A of rows 3 and 4 (and all other rows) are held at a low voltage reference, such as V ss , by turning on the reset transistors for those rows and keeping the reset transistors' drain voltage at low.
The process of reading the remaining rows of the image sensor are the same as for as for rows 1 and 2 . At any one instant in time, only one of the row select transistors is turned on.
In one actual embodiment, the transistors that form the reset transistor, the source follower transistor, and the row select transistor for a grouping of rows is typically formed in those areas of the imaging array that are outside of the actual photodiode and transfer gate pixel area. This will increase the fill factor of the pixel and provide additional balancing to the operation of the read out circuit.
The active pixels described above may be used in a sensor array of a CMOS image sensor 1101 . Specifically, FIG. 5 shows a CMOS image sensor formed in accordance with the present invention. The CMOS image sensor includes a sensor array 1103 , a processor circuit 1105 , an input/output (I/O) 1107 , memory 1109 , and bus 1111 . Preferably, each of these components is formed on a single N-type semiconductor silicon substrate and manufactured to be integrated onto a single chip using standard CMOS processes.
The sensor array 1103 portion may be, for example, substantially similar to the sensor arrays portions of image sensors manufactured by the assignee of the present invention, OmniVision Technologies, Inc., of Sunnyvale, Calif., as model numbers OV7630, OV7920, OV7930, OV9620, OV9630, OV6910, or OV7640, except that the pixels are replaced with the active pixels disclosed herein.
More specifically, the sensor array 1103 includes a plurality of individual pixels arranged in a two-dimensional array. In operation, as an image is focused onto the sensor array 1103 , the sensor array 1103 can obtain the raw image data.
The raw image data is then received by the processor circuit 1105 via bus 1111 to begin signal processing. The processor circuit 1105 is capable of executing a set of preprogrammed instructions (perhaps stored in memory 1107 ) necessary to carry out the functions of the integrated circuit 1101 . The processor circuit 1105 may be a conventional microprocessor, DSP, FPGA or a neuron circuit.
While the preferred embodiment of the invention has been illustrated and described, it will be appreciated that various changed can be made therein without departing from the spirit and scope of the invention.
The present invention has thus been described in relation to a preferred and several alternate embodiments. One of ordinary skill after reading the foregoing specification will be able to affect various changes, alterations, and substitutions of equivalents without departing from the broad concepts disclosed. It is therefore intended that the scope of the letters patent granted hereon be limited only by the definitions contained in appended claims and equivalents thereof, and not by limitations of the embodiments described herein.
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A CMOS image sensor that has reduced transistor count is disclosed. The individual pixels are formed by a pinned photodiode and a transfer transistor. An output node receives the signal from the photodiode via the transfer transistor. The output node is shared between multiple pixels. Further, a reset transistor is coupled between a selectable low voltage rail V ss or a high voltage reference V ref and the output node. The gate of an output transistor is then coupled to the output node. Both the reset transistor and output transistors are shared between multiple pixels.
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BACKGROUND OF THE INVENTION
This invention relates to a surgical device for lifting tissue to create an operative space in a patient for facilitating the performance of a surgical procedure. It also relates to a method of performing a surgical procedure within the patient using a surgical device to create or enlarge the operative space.
During conventional endoscopic surgery, the abdominal cavity of the patient is inflated to provide an operative space between the surgical site and adjacent bodily organs. In the conventional procedure, carbon dioxide gas is pumped into the abdominal cavity to raise the abdominal wall and create the operative space necessary to carry out the endoscopic procedure. Once the abdominal cavity is sufficiently "insufflated" with carbon dioxide gas, the desired diagnostic or therapeutic procedure can be performed with the use of instruments capable of the desired surgical manipulations at the surgical site. These instruments are sealed to prevent or minimize the escape of insufflation gas during the procedure.
Although carbon dioxide insufflation has provided an acceptable methodology for creating an operative space in the abdominal cavity during endoscopic surgery, it does have its drawbacks. When the insufflation gas is pumped into the abdominal cavity, it is pumped into the cavity at a pressure higher than that of the atmosphere in the room. This creates a positive pressure differential between the gas inside the abdominal cavity and the ambient room atmosphere, consequently exerting a force on the internal tissue structures within the abdominal cavity. The disadvantages of this phenomenon during the surgical procedure include the following:
a) pressure on the vena cava can reduce cardiac output,
b) pressure on the diaphragm can cause phrenic nerve irritation and reduced respiratory function,
c) carbon dioxide absorption may increase the need for ventilation,
d) potential hypercarbia and blood acidosis in respiratory compromised patients, and
e) tissue desiccation and cooling due to the dry cold gas present in the abdominal cavity.
There are other practical limitations with the use of carbon dioxide insufflation as well. These include the expense of the system for storing and pumping the gas into the abdominal cavity, and the difficulties when using suction during the surgical procedure to c lea r smoke or fluids from the operative site. Unfortunately, when suction is used inside the abdominal cavity for those purposes, it will naturally remove the carbon dioxide gas, decreasing the positive pressure inside the abdomen, thus sometimes causing a loss in the proper lift of the abdominal wall.
In view of the drawbacks attendant with carbon dioxide insufflation during endoscopic surgery, alternatives to this methodology have been proposed. In particular, numerous patents have been published which describe various mechanical lifts which are designed to elevate the abdominal wall during an endoscopic procedure to create the operative space. Examples of patents in this area are U.S. Pat. Nos. 5,309,896; 5,361,752; 5,402,772; 5,425,357; 5,450,843; 5,454,367; 5,465,711; 5,501,653; 5,505,689; 5,514,075; 5,520,609; 5,522,790; 5,527,264; 5,531,856; 5,562,603; 5,569,165; 5,575,759; 5,632,761; 5,634,883; 5,643,178; 5,676,636; 5,681,341; 5,690,607; 5,716,327 and 5,836,871. The mechanical wall lift devices described in these patents typically are initially inserted into the abdominal cavity, and then actuated to physically lift the interior tissue surfaces of the abdominal wall. In certain illustrated embodiments, balloon structures are designed to inflate inside the abdominal cavity and lift the interior abdominal wall. These balloon structures act like car jacks to separate the abdominal wall from the internal tissues. In other embodiments, "fan blade" style retractors operate by means of an external lifting mechanism, such as a mechanical lifting arm. The fan blades are attached to the lifting arm and then inserted into the abdominal cavity. The arm is then activated and then pushes against the abdominal wall to lift it.
Other examples of patents describing devices which mechanically lift the abdominal wall to provide an operative space include U.S. Pat. Nos. 5,398,671; 5,415,159; 5,415,160; 5,545,123; 5,183,033; 5,318,012; 5,353,785; 5,601,592; 5,716,326 and 5,613,939.
Although the mechanical wall lifting devices provide an alternative to conventional carbon dioxide insufflation, these devices have some significant drawbacks. A major drawback is that these devices must be initially deployed in the interior abdominal cavity and then actuated to lift the abdominal wall for creating the operative space. Unfortunately, these devices tend to be bulky and can create a significant obstruction in the cavity for the surgeon, thus making the performance of the desired operative procedure at the surgical site more difficult. The mechanical devices also require a bulky hoist mechanism that must be attached to the operating table or other support structure, or a surgical assistant must hold the abdomen up using direct upward muscular force. Further, the mechanical devices create less operative space than is needed to complete many surgeries because the space created with these devices is shaped more like a "tent" than a dome.
With respect to the mechanical devices which include an inflatable balloon, once the balloon is inflated, it will create direct pressure on internal tissue structures within the abdominal cavity. This direct pressure can cause problems, for example, reduced blood flow, or a reduction in excursion of the diaphragm with respiration. The "fan blade" retractor designs and methods apply a force near the incision site on the abdominal wall. The tissue surface area affected by the fan blade is small, thus significantly increasing the contact stress on the tissue, and potentially resulting in tissue damage.
Another device for lifting the abdominal wall to create an operative space within the abdominal cavity is described in U.S. Pat. No. 4,633,865. This device uses vacuum to lift the abdominal wall to perform examinations and surgical interventions within the abdominal cavity. The device consists of a cowling that is hermetically sealed against the exterior abdominal wall. The cowling has a central opening with an annular projection directed inwardly. The opening is temporarily closed using a lid, and vacuum is applied between the inner surface of the cowling and the exterior abdominal wall, causing the abdominal wall to be raised toward the cowling. With the wall raised toward the cowling, the lid over the central opening is removed and the abdominal wall can then be pierced. Subsequently, the lid covering the opening in the cowling can be removed, and instruments may be inserted through the opening, and into the abdominal cavity for examination and surgical interventions.
Although this device eliminates the need for carbon dioxide insufflation and represents an alternative to the mechanical wall lifts which must be deployed within the interior of the abdominal cavity, it has some significant drawbacks. The most significant drawback is that when the abdominal wall is lifted upon application of vacuum, the internal organs within the abdominal cavity will lift upwardly in tandem with the upward movement of the abdominal wall. This is so because a negative pressure develops in the abdominal cavity when the vacuum is applied to the exterior wall. As a result of this negative pressure created in the abdominal cavity, the internal organs will be displaced, and consequently lifted upwardly as the abdominal wall is lifted. As a result, the internal organs do not fall away and will remain positioned adjacent the abdominal wall. Consequently, the desired operative space between the abdominal wall and the internal organs for effectively carrying out the endoscopic surgical procedure will not be provided, and serious injury to these internal organs may occur during the surgical procedure if the required operative space is not created.
Another drawback to the vacuum-assisted device illustrated in U.S. Pat. No. 4,633,865 is that it does not describe an adequate mechanism for maintaining a vacuum seal to ensure adequate abdominal lift when a surgical instrument is inserted through the opening in the cowling and into the abdominal cavity during the endoscopic surgical procedure.
In view of the deficiencies inherent in the prior art devices for lifting the abdominal wall during an endoscopic surgical procedure to create an operative space, a device is needed which will address these inherent deficiencies. Specifically, the device and its method of use will eliminate the requirement for carbon dioxide insufflation of the abdominal cavity. Additionally, it will not create obstructions or barriers within the interior operative space, thus reducing surgeon inconvenience and patient risk. Further, the ideal device will lift the desired tissue without creating unwanted displacement of internal organs, ensuring that appropriate space between the lifted tissue and the internal organs is created. This ideal instrument would also preferably have the capability to provide and maintain lift even when surgical instruments or human digits are inserted through it to reach the surgical site, and the ability to have internal organs temporarily externalized through it while maintaining lift. Further, the ideal device will have at least one receptacle which is suitable for attaching and holding the various surgical instruments (including cameras) which the surgeon may employ, freeing the hands of the surgeon or assistant. Finally, it would certainly be advantageous if such a device were created which could be employed using less expensive surgical instruments which do not require seals to maintain an insufflated abdominal space or other operative space during the surgical procedure.
SUMMARY OF THE INVENTION
In one aspect, the invention is a vacuum-actuated tissue-lifting device for creating an operative space in a patient during a surgical procedure. The device comprises a shell, a vacuum port located on the shell, and an air conduit extending through the shell.
The shell of the tissue-lifting device is composed of a material substantially impermeable to air. The shell has a profile configured to surround a tissue surface of the patient. The shell has a contacting edge adapted to seal the device against the tissue surface of the patient. The shell defines an expansion cavity between the shell and the tissue surface of the patient prior to application of vacuum.
The vacuum port on the shell is in communication with the expansion cavity. When vacuum is applied through the vacuum port, the tissue surface of the patient is lifted into the expansion cavity toward the shell.
The air conduit extends through the shell and the tissue surface into the operative space of the patient. The air conduit is adapted to permit passage of air exteriorly of the patient into the operative space of the patient. When vacuum is applied through the vacuum port to lift the tissue surface toward the shell, air passes through the air conduit into the operative space to allow internal tissues of the patient to separate from the lifted tissue surface during the surgical procedure.
In another aspect of the invention, the invention is a method for performing a surgical procedure in an operative space of a patient. In the practice of the method, a vacuum-actuated tissue-lifting device is provided. The device comprises a shell and a vacuum port located on the shell. The shell is composed of a material substantially impermeable to air. It has a profile configured to surround the tissue surface of the patient. The shell has a contacting edge adapted to seal the device to the tissue surface of the patient. The shell defines an expansion cavity between the shell and the tissue surface of the patient prior to application of vacuum. The vacuum port is in communication with the expansion cavity. When vacuum is applied through the vacuum port, the tissue surface of the patient is lifted into the expansion cavity toward the shell.
The method comprises the steps of positioning the contacting edge of the shell of the tissue-lifting device onto the tissue surface of patient; applying a vacuum through the vacuum port of the tissue-lifting device so as to lift the tissue surface of the patient toward the shell of the device; providing an air passage exteriorly of the patient into the operative space of the patient while vacuum is applied; inserting a surgical instrument into the operative space of the patient through the shell of the tissue-lifting device and the tissue to be lifted; and using the surgical instrument in the operative space of the patient so as to perform the surgical procedure.
In a preferred embodiment of the invention, the tissue-lifting device of this invention has at least one entry port located on the shell, and a perforable membrane located on the entry port. In another preferred embodiment, an attachment receptacle is located on the shell to attach and hold surgical instruments which are required to perform the desired procedure.
The entry port provides an entry passageway exteriorly of the patient into the operative space of the patient when the tissue surface is penetrated. The perforable membrane blocks the passageway to substantially prevent passage of air into the expansion cavity when vacuum is applied through the vacuum port. The perforable membrane is conformable to, and sealingly engaged with, a surgical instrument inserted through the membrane and into the passageway of the entry port to minimize passage of air into the expansion cavity while using the surgical instrument in the operative space of the patient during the surgical procedure.
The device of this invention, and the method of this invention for performing a surgical procedure in an operative space of a patient, eliminate the requirement for carbon dioxide insufflation to lift the tissue surface of the patient for creating space for an operative procedure. The need for insufflation is eliminated because it is unnecessary to pump carbon dioxide gas into the desired operative space with the device or the method of this invention to lift the tissue surface.
Further, the device of this invention, and the method of this invention for performing a surgical procedure in an operative space of a patient, do not require the deployment of a mechanical lift within an interior operative space, which would undesirably create a barrier or obstruction for the surgeon during the operative procedure. In contrast to the mechanical lift devices which push against the interior tissue surfaces inside the operative space, the device of this invention is actuated using vacuum exteriorly of the desired operative space to lift the targeted tissue surfaces upwardly. Not only are obstructions or barriers avoided, but pressure points or stress areas resulting from contact of the mechanical lifting mechanisms with the targeted tissue surfaces are also avoided.
Significantly, the device of this invention in a preferred embodiment includes an air conduit extending through the shell for permitting passage of air exteriorly of the patient into the operative space of the patient. Consequently, when vacuum is applied through the vacuum port on the shell of the device, air passes through the air conduit into the operative space. This is important to eliminate the negative pressure which would otherwise be created within the targeted operative space as vacuum is applied to the expansion cavity between the shell and the tissue surface. Since negative pressure is avoided, tissues within the operative space of the patient will not be lifted upwardly in tandem with the tissue surface as it moves upwardly in response to the application of vacuum. As a result, a separation between the lifted tissue surface and tissues within the operative space is created, and a suitable operative space for the surgical procedure consequently can be established.
Similarly, the method of this invention for performing the surgical procedure specifies providing an air passage exteriorly of the patient into the operative space of the patient while vacuum is applied to ensure that undesirable displacement of internal organs of the patient does not occur. The air passage may be created prior to or during the application of vacuum. An air conduit may be used for creating the passage. If a conduit were used, then it may be inserted directly through the tissue layers. Alternatively, it could be inserted through the shell of the device and the tissue layers, or introduced internally through a surgical instrument, such as an endoscope, which is inserted into the operative space during the procedure.
In addition, the device in another preferred embodiment of this invention has an entry port located on the shell and a perforable membrane located on the entry port. Significantly, the perforable membrane is conformable to, and sealingly engaged with, a surgical instrument which is inserted through the membrane. Consequently, the perforable membrane located on the entry port will maintain an adequate vacuum seal to lift the tissue surface during the surgical procedure. Importantly, this seal will be maintained when an instrument is inserted through the perforable membrane because of the conformable nature of the membrane.
The device of this invention, and the method of this invention for performing a surgical procedure, can be used in any open or endoscopic surgical procedure, although the invention is especially targeted toward endoscopic applications. The device and method can be used, for example, during the removal of a gall bladder, hernia repair and endoscopic harvesting procedures, particularly procedures directed to the harvesting of the sapheinous vein for use as a coronary artery bypass graft. Other examples include, but are not limited to, laparoscopic assisted vaginal hysterectomy, neck surgery, oophorectomy, tubal ligation, splenectomy, Nissen fundoplication, vagotomy, nephrectomy, appendectomy, colectomy, organ biopsy, and exploratory laparotomy.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a preferred embodiment of the tissue-lifting device of the invention illustrated as it would be used on a surgical patient.
FIG. 2 is a plan view of the device of FIG. 1.
FIG. 3 is a side elevation view of the device of FIG. 1.
FIG. 4 is an end view of the device of FIG. 1.
FIG. 5 is a centerline section view of the device of FIG. 1.
FIG. 6 is a perspective view of the device of FIG. 1 covering a patient exhibiting a previously administered entry incision and illustrating the insertion of an optical trocar through the shell of the device.
FIG. 7 is a centerline section view of the device of FIG. 1 in conjunction with a side elevation view of a patient, partially in section, illustrating the placement of the trocar through the entry incision of the abdominal wall.
FIG. 8 is a perspective view like FIG. 7 wherein vacuum is applied to the cavity between the shell of the device and the abdominal wall surface of the patient and the trocar cannula acts as an air conduit to equalize the pressure in the abdominal cavity.
FIG. 9 is a view like FIG. 8 wherein the abdominal wall has risen into contact with the inner surface of the shell of the device.
FIG. 10 is a view like FIG. 9 wherein an endoscope has been inserted through the cannula of the trocar. Also illustrated is a second cannula shown projecting through the shell of the device and into the patient's abdominal cavity.
FIG. 11 is a perspective view of a portion of FIG. 1 illustrating an attachment supporting the endoscope which is used during the surgical procedure on the patient.
FIG. 12 is a side elevational view of the optical trocar cannula used in conjunction with providing an air passage into the abdominal cavity as illustrated in FIG. 8.
FIG. 13 is a proximal end elevational view of the cannula of FIG. 12.
FIG. 14 is a side elevation view of the optical trocar obturator illustrated in FIG. 6.
FIG. 15 is a proximal end elevational view of the obturator of FIG. 14.
FIG. 16 is a perspective view of the trocar whose elements are shown in FIGS. 12 and 14.
FIG. 17 is a plan view of the snap-on attachment receptacle shown in FIG. 11.
FIG. 18 is a side elevational view of the snap-on attachment receptacle of FIG. 17.
FIG. 19 is a perspective view of the snap-on attachment receptacle of FIG. 17.
FIG. 20 is a side elevational view of the additional cannula illustrated in FIG. 10.
FIG. 21 is a proximal end elevational view of the cannula of FIG. 20.
FIG. 22 is a perspective view of the cannula of FIG. 20.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Although this invention will be described in connection with its most preferred embodiment as depicted in the figures, the reader will easily recognize that numerous additional embodiments will be well within the scope of the invention defined by the claims which appear below. The detailed description which follows is intended merely to illustrate the preferred aspect of the invention, and is not intended to limit the scope and spirit of the claimed invention in any way. In this regard, certain definitions for the terms used in the claims are appropriate to ensure that the reader will not think to limit the scope of these terms to the specific preferred embodiments described in this detailed description. These definitions are given by way of example only, without limitation.
The term "surgical procedure" means collectively all therapeutic and diagnostic procedures, both open and endoscopic. It also includes "field" surgeries, for example, emergency, remote or mobile procedures for exploratory, therapeutic and diagnostic applications.
The term "operative space" means any working space created in the patient beneath tissue which is lifted using the device of the invention or practicing the method of this invention, including the space created as a result of expanding natural pre-existing separations between tissue planes, or separations which are surgically created.
The term "shell" means any structural member or collection of members which defines the expansion cavity between the member(s) and the tissue surface of the patient prior to application of vacuum.
Now that critical elements of the claimed invention have been defined, we can now turn our attention to the illustrations which accompany this specification to more fully describe the preferred embodiment. Referring initially to FIGS. 1-5, the preferred vacuum-actuated tissue-lifting device 30 of this invention particularly adapted for lifting an external abdominal surface 31 of a human patient 32 is illustrated. The device has an impermeable shell 33, which is configured to conform to the exterior surface of the patient, once the device is positioned on the external surface of the abdominal wall and vacuum is applied.
The shell is advantageously composed of a medical grade, clear molded plastic such as a polycarbonate approved for tissue contact. Other possibilities for the composition of the shell include malleable materials, particularly metals and metal alloys, such as medical grade, annealed stainless steel, aluminum and titanium.
Alternatively, high durometer elastomeric materials, for example polyurethanes, can be used. Optimally, the shell is composed of a material which exhibits the flexibility required to conform to the contour of the patient, yet exhibit the strength needed to support the necessary operating loads during the surgical procedure.
In the embodiment depicted in the figures, the shell is a unitary member. Alternatively, the shell may include multiple members to provide specific properties. Further, the shell may have multiple compartments to isolate various interior sections of the shell if desired. Additionally, the thickness of the shell may vary to provide different physical properties at various positions on the shell. For example, the shell may have reduced thickness at its periphery adjacent the tissue surface to increase the flexibility at the tissue surface and to enhance the sealing capability of the shell when it is positioned on the external tissue surface. In any event, the shell may be designed so that its physical properties are tailored to meet the specific needs of the surgical patient and the particular operative procedure being performed.
Referring again to FIGS. 1-5, the shell has a contacting edge 34 at its outer periphery which initially comes into contact with the exterior surface of the abdominal wall which is desired to be lifted. The contacting edge, when positioned on the exterior tissue surface, is adapted to seal the device against the tissue surface of the patient when vacuum is applied. An elongated vacuum port 35 is positioned mid-line on the shell and provides a vacuum passage through the shell and membrane into the expansion cavity (to be described later in connection with FIG. 7). A tubular conduit 36 is attached to the vacuum port, and the conduit is connected to a vacuum source (not shown).
The insertion and withdrawal of various surgical instruments, including visualization devices such as endoscopes, through the shell of the device is carried out through a plurality of entry ports 37 located on the shell. The entry ports provide an entry passageway through the shell and into the patient at the desired surgical site during the operative procedure. The entry ports each have a perforable membrane 38 located on the entry port. The perforable membranes block the entry passageway to substantially prevent the passage of air through the shell of the device when vacuum is applied through the vacuum port.
The perforable membranes located on the entry ports of the shell may be composed of any material which is substantially impermeable to air and will be conformable to, and sealingly engaged with, a surgical instrument which is inserted through the membrane during the surgical procedure. For example, the membrane may be composed of a medical grade, elastomer such as silicone which exhibits a hardness in the range of 35-60 Shore A durometer. Alternatively, other elastomers which can be used include neoprene, santoprene and polyisoprene. These elastomers may be co-molded to bond to the shell. Alternatively, the membrane may be composed of an elastomer-plastic composite, for example an elastomer backed by a plastic sheet so that the elastomer will conform to seal around an instrument inserted through the membrane, and the plastic sheet will provide the support necessary for the loading exerted on the membrane when instruments are inserted into or withdrawn form the patient. Preferably, the membrane is an elastomer co-molded onto the shell.
In a particularly preferred embodiment, an adhesive backing may be applied to the perforable membrane or, alternatively, it can be applied to the plastic sheet if the membrane is composed of an elastomer-plastic composite. The adhesive backing may be desirable to adhere the tissue to the shell once the exterior tissue surface is lifted to come into contact with the interior surface of the shell. This approach is illustrated in FIG. 5 where the stippled area represents an adhesive coating applied on the interior surface of the shell to maintain contact (and therefore a seal) between the exterior tissue surface and the interior surface of the shell.
Although the perforable membrane is preferably composed of an elastomer or an elastomeric-plastic composite, it may be fabricated from other materials. For example, the membrane may be in the form of a bellowed rubber grommet attached to the shell, a gel-like material or a closed cell foam.
Continuing to refer to FIGS. 1-5, in addition to the entry and vacuum ports, the device also includes a plurality of attachment receptacles 39 located on the shell. Each attachment receptacle is designed to receive an instrument holder 40, for example as depicted in FIGS. 17, 18 and 19, for fixing and maintaining the location of various surgical instruments which are used in conjunction with the device of this invention during the surgical procedure. Finally, it is now worthy to point out that the contacting edge 34 of the shell has a peripheral underlayer 41 extending radially inwardly from the contacting edge to promote the sealing contact between the exterior tissue surface and the shell.
Referring now to FIGS. 6-11, the methodology by which the tissue-lifting device of this invention can be used to create an operative space within the surgical patient is illustrated. Turning initially to FIGS. 6 and 7, the contacting edge of the shell of the device is initially positioned on to the tissue surface of the patient, which in this case is the exterior abdominal surface of the human patient (also depicted nicely in FIG. 1). An entry incision 42 through the exterior abdominal surface of the patient is made, and an optical trocar assembly 43 is inserted through a perforable membrane of one of the entry ports on the shell in the direction of the entry incision. As illustrated in FIG. 7, the perforable membrane conforms nicely to the outer diameter of the trocar assembly. Downward pressure is applied on the trocar assembly to cause a penetration through the various tissue layers 44 of the patient until the obturator has fully penetrated the tissue layers and has entered the interior abdominal cavity under visual guidance from a camera in the optical trocar.
The optical trocar assembly 43 is shown in more detail in FIGS. 12-16. The assembly includes a hollow optical obturator 45 which has a handle 46 for manipulation. The obturator has a transparent tip 47 which is shaped for passage through tissue. The obturator is received in a cannula 48.
As illustrated in FIG. 7, once the optical trocar assembly is properly positioned within the interior abdominal cavity 49, a laparoscope 50 may be inserted through the hollow obturator to observe the interior abdominal cavity during a portion of the minimally invasive surgical procedure. Also noteworthy is that the shell of the device defines an expansion cavity 51 between the exterior abdominal surface 31 of the patient and the interior surface of the shell.
Referring now to FIG. 8, the laparoscope and hollow optical obturator are removed from the optical trocar assembly and the cannula 48 is left intact.
Significantly, the cannula acts as an air conduit to provide for the passage of air from the operating room into the interior abdominal cavity of the patient. Vacuum is then applied through the vacuum port 35 of the shell, which consequently pulls a vacuum from the expansion cavity, thus lifting the exterior abdominal surface 31 of the patient toward the shell (see the directional arrows for the application of vacuum through the vacuum port). Significantly, as illustrated in FIGS. 8 and 9, as the vacuum is applied to lift the exterior abdominal surface toward the shell, room air will pass through the cannula air conduit into the interior abdominal cavity 49 so that the internal tissues 52 of the patient can separate from the lifted abdominal tissue surface (see the directional arrows at the proximal and distal ends of the cannula air conduit for the passage of air from the operating room into the interior abdominal cavity). In this manner, an operative space in the interior abdominal cavity between the lifted abdominal tissue and the internal tissues of the patient is created for safely performing a surgical procedure.
Referring now to FIGS. 10 and 11, since an adequate operative space has been created in the interior abdominal cavity, a surgical procedure can safely be performed. In these illustrations, the laparoscope 50 has been reinserted into the operative space, and another surgical instrument conduit 53 has been inserted through one of the perforable membranes on the shell to carry out the desired surgical procedure. The instrument conduit 53 is illustrated in more detail in FIGS. 20-22.
FIG. 11 further illustrates the benefits of attaching a flexible instrument holder 40 to one of the attachment receptacles 39 located on the shell. As illustrated in FIGS. 17-19, the instrument holder has a receiving base 54 at its proximal end for mating with the attachment receptacle, and a spring-loaded clip bracket 55 at its distal end for grasping the shaft of a desired surgical instrument, e.g. a laparoscope. A plurality of joint links 56 joins the receiving base at its proximal end to the clip bracket at its distal end. The joint links provide the required degree of flexibility to position the attached surgical instrument at a desired location while maintaining that fixed position during the procedure. Of course, it is envisioned that other instrument holders may be utilized in the practice of the claimed invention. For example, an instrument holder may include a ball turret style locking mechanism to allow rotation of the attached instrument independent of actual movement of the instrument.
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A vacuum-actuated tissue-lifting device and method for performing a surgical procedure in an operative space of a patient are disclosed. The preferred device has a shell with a profile configured to surround a tissue surface of the patient, a vacuum port located on the shell for applying a vacuum between the shell and the tissue surface, and an air conduit extending through the shell to permit air to pass into the operative space of the patient when vacuum is applied. In a preferred embodiment, the device has an entry port located on the shell and a perforable membrane located on the entry port to provide a seal when a surgical instrument is inserted through the membrane during the procedure. The device and method of the invention eliminate the need for carbon dioxide insufflation, mechanical lifting devices which create obstructions and high stress zones on tissues within the operative space created, and unwanted displacement of internal organs when the targeted tissue surface is lifted.
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BACKGROUND OF THE INVENTION
The present invention is directed generally to prestressed concrete tanks used for storing liquids such as water and, more particularly, to such prestressed concrete tanks having means for preventing the wall of the tank from rotating and/or from shifting laterally relative to the tank foundation when subjected to shearing forces, such as occur during backfilling earthquakes, and the like.
As a brief background, conventional prestressed concrete tanks generally comprise an annular-shaped supporting foundation embedded in the earth and a vertically extending cylindrical wall structure of concrete about a cylindrical steel shell. The outer concrete portion of the wall structure is generally prestressed by a plurality of circumferential steel wires under a tension of up to about 140,000 psi or more. Prestressing of the wall structure of the tank maintains the concrete in compression even when the tank is filled with a liquid. The wall structure of the tank is not necessarily fixed to the foundation, but, may instead simply rest on the foundation so that the wall structure is able to move or float horizontally with respect to the foundation. An elastomeric gasket type seal (e.g. PVC) is utilized between the wall structure and the foundation to prevent liquid contained in the tank from escaping between the bottom of the wall structure and the foundation.
The capability for limited movement of the wall structure relative to the foundation is necessary during the construction of the tank and during its service life since, as the prestressing circumferential steel wires are stressed, the radius of the wall structure is reduced as well as when the concrete material of the wall structure cures. Furthermore, when the completed tank is filled with or simply contains a liquid, hydrostatic pressure of the liquid causes a radial expansion of the wall structure. In both instances, the wall structure must move relative to the foundation of the tank to prevent harmful stresses from being created, both in the wall structure and the foundation.
However, a capability of almost unlimited movement of the wall structure relative to the foundation is undesirable and even catastrophic when the wall structure is subjected to large horizontal shearing forces. An example of the occurrence of such shearing forces is during the backfilling of the tank. To be more specific, in many instances the terrain on which a tank is to be constructed is not level but is instead sloped, e.g., on the side of a hill. Consequently, prior to construction of the tank, earth is excavated from the hillside to provide a level base for the tank. Once the tank is completed, earth is backfilled along the uphill side of the wall structure of the tank to insure adequate drainage and to prevent erosion about the foundation of the tank. Backfilling on only a portion of the wall structure, however, creates shearing forces which tend to displace the wall structure off the foundation in the downhill direction, or at least tend to cause the wall structure to slide across the foundation. Another example of the occurrence of such forces is during an earthquake or earth tremor wher unequal shearing forces on the tank can be expected from any direction and which will tend to displace the wall structure.
Consequently, it is oftentimes necessary to provide means in a concrete tank which can help resist the occurrence of these shearing forces and thereby help prevent large displacements of the wall structure of the tank relative to the foundation while still allowing for necessary limited movement of the wall structure during construction of the tank and upon filling the completed tank with liquid.
An example of a known prestressed concrete tank which does include such means is disclosed in U.S. Pat. No. 2,932,964 to Dobell. In this tank, an overlap between an elevated peripheral step on the foundation and a protrusion on the interior of the wall structure provides a key to assure that the tank will stay on its foundation during earthquakes and to maintain the tank in position when the tank is backfilled unevenly and movement occurs. However, means are not provided in the disclosed tank to prevent rotational displacement as well as lateral displacement of the wall structure relative to the foundation.
Furthermore, U.S. Pat. No. 3,233,376 to Naillon et al discloses structural shear units adapted for use in concrete tanks. These units are devices which provide a connection between a supporting structure such as a tank foundation and a supported structure such as a tank wall, and which permit relative motion due to loading, prestressing or seismic stress. The disclosed structural shear units each comprise a lower member and an upper member slidably supported on the lower member, the members being respectively secured to the supporting structure and to the supported structure. The members have mutually engageable elements such as pairs of laterally directed abutments extending horizontally generally along the axis of the desired free sliding movement for restraining or limiting horizontal sliding motion between the members in the direction perpendicular to the axis. To reduce friction, an anti-friction pad such as a sheet of porous metal inpregnated with a lubricant is placed between the members.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide means for resisting shearing forces in a concrete-type tank in which the sealing means is less complicated and less expensive.
Another object of the present invention is to provide means for resisting shearing forces in a concrete-tye tank which are relatively easily fabricated and whose installation can easily be integrated in conventional methods for the construction of such tanks.
A further object of the present invention is to provide shear blocks for use in a prestressed concrete tank which can resist shearing forces on the tank caused, for example, by backfilling, earthquakes, and the like, which forces could normally cause displacement of the tank wall structure relative to the foundation.
A further object of the present invention is to provide a method for making watertight, prestressed concrete tanks wherein means such as shear blocks are included in the tanks to resist shear forces on the tanks caused by, for example, backfilling, by earthquakes, and the like.
Briefly, these objects are achieved by the present invention which in its broader aspects comprehends use of at least two shear blocks in a concrete-type tank having a foundation and a wall structure to help resist shearing forces between the wall structure and the foundation, the shear blocks each comprising a mass of reinforced concrete material in the general shape of an elongated hexahedron. The present invention also includes a tank comprising a foundation having a generally horizontal suporting surface and at least two shear blocks having sufficient height to project upwardly from the top of the supporting surface so as to be partially surrounded by the wall structure which is sealingly supported on the supporting surface.
The present invention further comprehends a method for making a tank which comprises a foundation having a supporting surface and a wall structure on the supporting surface, the method comprising the steps of (a) forming the foundation with a generally horizontal supporting surface so as to integrally include at least two shear blocks extending upwardly from the top of its supporting surface, (b) constructing a vertical portion of the wall structure of the tank on the supporting surface of the foundation adjacent to each shear block so as to include a liquid seal means between the vertical wall structure portion and the supporting surface of the foundation, and (c) completing the remainder of the wall structure so as to partially enclose the projecting portions of each of the shear blocks, but also so as to include means forming a bond breaker between the remaining wall structure and the supporting surface. Alternatively, the method may comprise the steps of (a) forming the foundation with a generally horizontal support surface so as to include at least two cavities therein, (b) constructing a vertical portion of the wall structure of the tank on the supporting surface of the foundation adjacent to each cavity so as to include a liquid seal means between the vertical wall structure portion and the supporting surface of the foundation, (c) placing a preformed shear block in each cavity, each shear block having a portion extending vertically upwardly beyond the top of the supporting surface of the foundation, and (d) completing the remainder of the wall structure so as to partially enclose the projecting portions of each of the shear blocks, but also so as to include means forming a bond breaker between the remaining wall structure and the supporting surface.
Further objects, advantages and features of the present invention will become more fully apparent from a detailed consideration of the arrangement and construction of the constituent parts as set forth in the remainder of the specification taken together with the accompanying drawing.
DESCRIPTION OF THE DRAWING
FIG. 1 is a perspective view of one embodiment of a shear block in accordance with the present invention,
FIG. 2 is a plan view of the foundation for a prestressed concrete tank illustrating a preferred placement of shear blocks when backfilling shear forces are expected on the tank,
FIG. 3 is an enlarged view of a portion of the foundation shown in FIG. 2,
FIG. 4 is a vertical cross-sectional view taken along a radius of a prestressed concrete tank utilizing shear blocks as shown in FIG. 1, and
FIG. 5 is another vertical cross-sectional view of the prestressed tank as shown in FIG. 4, the view being transverse to the view shown in FIG. 4.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to FIG. 1, one embodiment of a shear block 10 in accordance with the present invention is shown which is adapted to be utilized in a prestressed concrete tank. Shear block 10 is generally of an elongated box-type configuration except that front end surface 12 has a greater height than back end surface 14, such that the top side surface 16 of the block 10 slopes downwardly relative to the bottom side surface 18 of the block. The shape of the shear block 10 can be generally described as an elongated hexahedron having generally rectangular end surfaces 14 and 12, generally rectangular top and bottom surfaces 16 and 18, and generally trapezoidal side surfaces 17 and 19. Although the various surfaces may all be planar (the opposite side surfaces 17 and 19 may, however, be both curved as if forming segments of coincident cylinders), all opposite surfaces may not be parallel. In this regard, and as noted above, the top side surface 16 will converge towards the bottom side surface 18 as it extends from the front end surface 12 to the back end surface 14. In addition, the generally rectangular end surfaces 14 and 12 will converge to some extent towards one another, i.e., towards a distant imaginary common intersection line. More specifically, they will converge towards an imaginary vertical center line which will vertically pass through the center of the wall structure of the tank in which they are used, thus allowing for free inward movement of the wall structure (as will be better understood by the discussion which follows). Depending on the size of the tank and the size (diameter) of the wall structure of the tank in which they are used, the convergence of the end surfaces 14 and 12, as defined above, will vary.
The preferred shear blocks 10 of the invention are formed of concrete material which has been solidified around steel reinforcing bars (indicated in FIG. 4 only).
One situation wherein shear blocks 10 are advantageously used in a prestressed concrete tank is illustrated in FIGS. 2-5, which relate to a situation wherein shear forces from backfilling are encountered. FIG. 2 is a plan view of foundation 20 of a circular prestressed concrete tank showing a preferred location for shear blocks 10 about the circumference of the foundation. It should be realized that foundation 20 as illustrated is only that portion of the complete foundation which supports the wall structure for the tank. The complete foundation would, of course, extend across and fill in the portion defined by supporting foundation 20.
In FIG. 2, arrow A indicates the uphill direction of the terrain on which foundation 20 is located. In this embodiment, shear blocks 10 are placed in foundation 20 on the uphill arc of about 53° from direction B perpendicular to the uphill direction and an adjoining downhill arc of about 48° from direction B, the total arc comprising a segment of less than about 100°. Shear blocks 10 are located in foundation 20 such that the blocks project upwardly from the supporting surface of the foundation and the larger front surface 12 of each block faces generally uphill.
The placement of shear blocks 10 in foundation 20 is more clearly shown in FIG. 3 which is an enlarged plan view of a portion of the foundation shown in FIG. 2. A series of shear blocks 10 are partially embedded within cavities (not shown) in foundation 20 such that front surfaces 12 face generally uphill. As is illustrated, shear blocks 10 of the series which are nearer the uphill side of the foundation may have a greater length than those shear blocks nearer the downhill side.
Overlying foundation 20 are an inner annular bond breaker 30 and an outer annular bond breaker 31, the outer bond breaker 31 preferably having square openings therein which contain bearing pads 32. Bond breakers 30 and 31 and bearing pads 32, when needed, help provide a flexible barrier between foundation 20 and a vertical tank wall (not shown) which is supported by the foundation. Bond breakers 30 and 31, and particularly pads 32, also help provide a smooth surface so that the wall structure (not shown) of the tank can easily move relative to foundation 20 during prestressing and the like. Without gaskets 30 and 31, and pads 32, if used, any movement of the wall structure relative to foundation 20 would be between concrete surfaces which, due to high friction generated, could cause structural damage to the tank.
The interaction among shear blocks 10, the foundation, and the wall structure of a prestressed concrete tank are shown in FIGS. 4 and 5 which are cross-sectional views of a portion of a complete tank, the interior portion of the tank in FIG. 4 being to the right. In these Figures, shear block 10, having internal reinforcing bars 42, rests in a cavity 44 formed in foundation 20. As is apparent, cavity 44 is of a depth such that shear block 10 projects a certain distance above the top of the supporting surface of foundation 20.
Wall structure 50, supported by foundation 20 and shear block 10, comprises an inner concrete portion 52 reinforced by steel bars 54, cylindrical steel shell 56 and outer concrete portion 58 also having reinforcing bars 54. Outer concrete portion 58 is prestressed by circumferential wires 60 in a conventional manner. Separating wall structure 50 from foundation 20 and block 10 are bond breakers 30 and 31 and pads 32, as were previously illustrated in FIG. 3. Sealing means 62, comprising tubular bulb 64 and extending arms 66 filled with solidifiable material 68, such as epoxy, helps to provide a fluid-tight seal between wall structure 50 and foundation 20.
To further explain the purpose and effect of the use of shear blocks 10 in accordance with the present invention, attention is again directed to FIG. 2 which shows a preferred placement of shear blocks 10 in a tank relative to the terrain on which the tank is constructed. Once the tank is fully constructed, it is necessary to backfill with earth on the uphill side of the tank to provide adequate drainage and thereby to prevent erosion of the earth adjacent to the foundation. If the slope of the terrain is quite steep, earth may have to be backfilled almost to the top of the wall structure on the uphill side while little or no backfilling is necessary on the downhill side. Consequently, backfilling in this manner creates large shear forces on the tank generally in the downhill direction. The use of shear blocks 10 tends to resist these shear forces and help prevent displacement of the wall structure relative to the foundation. By visualizing a top view of the tank, shear blocks 10 form an arch with the wall structure to resist the shear forces caused by backfilling. Since the forces are first resisted by the furthermost uphill shear blocks 10, preferably those blocks are larger in size than the remaining blocks. In addition, by having the larger front face 12 of shear blocks 10 facing uphill, a larger effective area is available to resist forces while minimizing the shear block volume.
It should be realized, however, that, if desired, blocks 10 could be placed about the entire periphery of foundation 20 to resist the forces caused by backfilling. Such a placement is, however, less preferred due to the extra time and labor required to install additional shear blocks which are not really necessary for this purpose. In addition, other placement patterns for shear blocks than that shown in FIG. 2 could be utilized, the particular placement pattern depending upon the anticipated forces to which the tank will be subjected.
According to another embodiment of the invention, whenever shear blocks 10 in accordance with the present invention are primarily utilized in a tank to resist shearing forces caused by anticipated earthquakes, the blocks will generally be regularly placed about the entire periphery of foundation 20 as opposed to only a portion as shown in FIG. 2. Such a placement of shear blocks 10 may be necessary since shear forces caused by earthquakes can act on the tank from any direction. By using shear blocks 10 in a tank which may be subjected to the force of an earthquake, displacement or rotation of wall structure 50 relative to foundation 20 may be prevented. In this embodiment, the front and back end surfaces 12 and 14 may be of the same size, such that the upper side surface 16 may in fact be parallel with bottom side surface 18, i.e., since a particular direction of shearing displacement, for which provision must be made, cannot be anticipated.
In one method for constructing a prestressed concrete tank as shown in the drawings, foundation 20 is first cast about appropriate reinforcing bars 54 to a generally circular shape. During casting of foundation 20, cavities 44 of appropriate size are formed in the foundation in the locations shown in FIG. 2. Sealing means 62 and steel shell 56 are then erected, along with appropriate reinforcing bars 54, and annular bond breaker 31 and pads 32 (if used) are placed on the supporting surface of foundation 20 on the outside of the shell. Concrete material is then pneumatically applied to the outer surface of shell 56 and on top of an inner part of bond breaker 31 to form an inner vertical part of outer wall portion 58, extending from the steel shell 56 up to the inner edges of cavities 44. After this, the annular bond breaker 30 is placed on the inside of the shell, and then concrete material is applied to the inside of the shell and on top of the bond breaker 30 to form the inner wall portion 52. Shear blocks 10 of a length and width approximately equal to cavities 44, but of greater height, are then placed in the cavities and a bond breaker material is placed on the top side surfaces 16. Finally, the remainder of outer wall portion 58 of wall structure 50, including prestressing, is then completed; however, it should be noted that the outer wall 58 preferably, but not necessarily, does not extend beyond the outer edge of the shear blocks 10, in any event so as to leave side surfaces 19 of the shear blocks uncovered with any of the outer wall portion 58. This allows for free inner movement of the outer wall portion 58 and the wall structure 50 while retaining the liquid seal between the wall structure 50 and the foundation 20.
It should be noted that during construction of the tank, the inner surface of cavities 44 and associated shear blocks 10 are adjacent to the outer surface of outer wall portion 58 prior to prestressing. Once wall structure 50 is prestressed and the concrete material of the wall structure 50 completely cured, the outer surface of the outer wall portion 58 will become spaced further from the inner surfaces of shear blocks 10 due to radial contraction of the wall structure. Then, when wall structure 50 is completed, a space will remain between the inner surface of shear blocks 10 and the wall structure so as to allow for radial expansion of the wall structure due to hydrostatic pressure of a liquid contained in the tank.
As was described previously, the use of shear blocks 10 in a prestressed concrete tank tends to resist shear forces between foundation 20 and wall structure 50 of the tank caused by, for example, backfilling of the tank, or earthquakes. Thus, a tank utilizing such shear blocks 10 will have a greater ability to withstand such shear forces and will thereby provide a tank having improved stability and fluid tightness under adverse conditions.
Furthermore, the use of shear blocks 10 also helps to resist forces which might cause the wall structure to rotate circumferentially relative to the foundation. By utilizing the preferred shape for shear blocks 10 in FIG. 1 and placing the blocks such that the larger front surface 12 is directed towards the anticipated forces, a greater area of the blocks is exposed to the forces and thereby provides greater stability for the tank without utilizing massive blocks.
Although the above-described preferred embodiment utilizes a single unitary shear block 10 within each cavity 44 of foundation 20, it is within the scope of the present invention to utilize two or more individual shear blocks within a single cavity. Each shear block 10 may then be made of a corresponding smaller size so as to facilitate handling and placement of the blocks within cavities 44 of foundation 20. In addition, and according to another embodiment of the invention, instead of comprising separately formed elements, shear blocks 10 could be integrally formed during the construction of foundation 20 so that the shear blocks comprise integral projections from the foundation. This alternative is perhaps less preferred since the projecting shear blocks 10 may interfere with or impede the construction of outer wall portion 58 of the wall structure 50.
The particular size of shear blocks 10 of the present invention is not believed to be critical. The size of blocks 10 will generally vary according to the magnitude of the expected forces to be resisted and the strength of the material used to fabricate the blocks. As was set forth previously, when shear blocks 10 are used to resist shear forces caused by backfilling, preferably the blocks vary in size depending upon their proximity to the expected forces.
To further illustrate the present invention, the following example is given as a particular application of the subject shear blocks in a prestressed concrete tank. It should be realized that the example is presented for the purpose of illustration only and the example does not limit the invention as has heretofore been described.
In a particular application of the present invention in a tank having an outer diameter of approximately 140 feet, thirty shear blocks 10 were utilized on each side of foundation 20, the blocks placed in a pattern as illustrated in FIG. 2. In each group of thirty shear blocks 10, fifteen are on each side of a line perpendicular to the uphill direction. The fifteen downhill shear blocks 10 and the adjacent group of twelve uphill blocks are all of a shape as shown in FIG. 1 and have a length of about two feet, a width of ten inches, a front height of about eight inches and a rear height of about six inches.
Adjacent to the uphillmost block 10 of the twenty-seven identical blocks is a slightly larger block of similar shape having a length of about three feet and the same other dimensions. Adjacent to this latter shear block 10 is a slightly larger block also of similar shape having a length of about four feet, a width of about ten inches, a front face height of ten inches and a rear height of about seven inches. The final shear block 10 nearest to the uphill side of the tank has a length of about five feet, a width of about ten inches, a front face height of about seven inches. All shear blocks 10 are placed in cavities 44 of corresponding lengths and widths and which have a depth of about four inches. Blocks 10 are all spaced about two feet from one another.
While the present invention has been described with reference to particular embodiments thereof, it will be understood that numerous modifications may be made by those skilled in the art without actually departing from the spirit and scope of the invention as defined in the appended claims.
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Disclosed is a prestressed concrete tank comprising a foundation having a generally horizontal supporting surface and a wall structure mounted on the supporting surface. The generally horizontal supporting surface is provided with at least two shear blocks which have sufficient height as to project upwardly from the top of the supporting surface. The wall structure supported by the supporting surface partially surrounds the projecting portion of the shear blocks in a fashion so as to allow for the wall structure to be sealingly supported by the supporting surface; at the same time, however, the shear blocks tend to resist shearing forces on the tank caused by backfilling, earthquakes and the like, which could cause displacement and/or rotation of the tank wall structure relative to the foundation. The shear blocks may be formed as integral portions of the generally horizontal supporting surface or may comprise separate, generally box-like elements which are positioned within cavities formed in the supporting surface.
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CROSS REFERENCE TO RELATED APPLICATIONS
The present application is a divisional of U.S. patent application Ser. No. 12/317,351, filed Dec. 22, 2008, entitled, “DETECTION AND RECOVERY OF HARQ NAK-TO-ACK FEEDBACK ERROR IN WIRELESS COMMUNICATIONS SYSTEMS,” which claims priority to U.S. Provisional Patent Application No. 61/134,188 filed Jul. 7, 2008, entitled, “Techniques and Improvements for Broadband Wireless Networks,” the entire specifications of which are hereby incorporated by reference in their entireties for all purposes, except for those sections, if any, that are inconsistent with this specification.
BACKGROUND
Wireless communications networks following the protocols of the standard known as IEEE 802.16 may use various types of message tracking and may use multiple levels of acknowledgement in order to promote high traffic throughput and reliable communications in the networks. Hybrid Automatic Repeat Request (HARQ) protocols may be used at the PHY level for fast response, while Automatic Repeat Request (ARQ) protocols may be used at the MAC level when the HARQ protocols don't provide sufficient reliability. For message tracking, each transmission may contain a HARQ Channel ID (ACID) to track the message and its acknowledgement. The available ACID's for use between a base station and a particular subscriber station are limited in number and must be repeatedly recycled. A single-bit parameter called a HARQ Sequenc Number (AI_SN) may be associated with each ACID to indicate whether the current transmission is a new transmission or a retransmission of a previously NAK'd transmission. A retransmission will contain the same ACID and same AI_SN as the original transmission that was NAK'd. A new transmission is indicated when the AI_SN has the opposite value that it had the last time the current ACID was used.
To handle acknowledgements, errors in a received transmission are initially detected and handled at the PHY layer using HARQ. If the transmission is received correctly, the receiving device may transmit a PHY-level ACK back to the originating device, which then removes that transmission from its PHY-level buffers. But if the transmission is received incorrectly, a PHY-level NAK is transmitted back, still following the HARQ protocol, and the originating device retransmits the data. If the PHY-level retransmissions also fail a certain number of times, this failure is then passed to the MAC layer of the receiving device, which initiates a MAC-level NAK using the ARQ protocol, so that the originating device can take more drastic action. MAC-level exchanges of this type are much more time-consuming, which hurts the efficiency of communications between the two devices. Unfortunately, HARQ ACKs and NAKs may be expressed by a single bit that is not protected by CRC or other error detection techniques, so the originating device may erroneously receive a HARQ NAK as a HARQ ACK without knowing of the error. It would then clear the associated transmission from its PHY-level buffer, thus losing any chance to retransmit the data until the receiver's MAC layer notifies the originating device of the missing data. At that point, recovering from the error is much more difficult and time-consuming.
BRIEF DESCRIPTION OF THE DRAWINGS
Some embodiments of the invention may be understood by referring to the following description and accompanying drawings that are used to illustrate embodiments of the invention. In the drawings:
FIG. 1 shows a flow diagram of a method of choosing an ACID for a new transmission, according to an embodiment of the invention.
FIG. 2 shows a flow diagram of a method of determining that a previously transmitted NAK was received as an ACK by the other device, according to an embodiment of the invention.
FIGS. 3, 4, 5 and 6 show different scenarios for detection of an incorrectly received ACK, according to various embodiments of the invention.
FIG. 7 shows a block diagram of a base station and an associated subscriber station, according to an embodiment of the invention.
DETAILED DESCRIPTION
In the following description, numerous specific details are set forth. However, it is understood that embodiments of the invention may be practiced without these specific details. In other instances, well-known circuits, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.
References to “one embodiment”, “an embodiment”, “example embodiment”, “various embodiments”, etc., indicate that the embodiment(s) of the invention so described may include particular features, structures, or characteristics, but not every embodiment necessarily includes the particular features, structures, or characteristics. Further, some embodiments may have some, all, or none of the features described for other embodiments.
In the following description and claims, the terms “coupled” and “connected,” along with their derivatives, may be used. It should be understood that these terms are not intended as synonyms for each other. Rather, in particular embodiments, “connected” is used to indicate that two or more elements are in direct physical or electrical contact with each other. “Coupled” is used to indicate that two or more elements co-operate or interact with each other, but they may or may not be in direct physical or electrical contact.
As used in the claims, unless otherwise specified the use of the ordinal adjectives “first”, “second”, “third”, etc., to describe a common element, merely indicate that different instances of like elements are being referred to, and are not intended to imply that the elements so described must be in a given sequence, either temporally, spatially, in ranking, or in any other manner.
Various embodiments of the invention may he implemented in one or any combination of hardware, firmware, and software. The invention may also be implemented as instructions contained in or on a computer-readable medium, which may be read and executed by one or more processors to enable performance of the operations described herein. A computer-readable medium may include any mechanism for storing, transmitting, and/or receiving information in a form readable by one or more computers. For example, a computer-readable medium may include a tangible storage medium, such as but not limited to read only memory (ROM); random access memory (RAM); magnetic disk storage media; optical storage media; a flash memory device, etc. A computer-readable medium may also include a propagated signal which has been modulated to encode the instructions, such as but not limited to electromagnetic, optical, or acoustical carrier wave signals.
The term “wireless” and its derivatives may be used to describe circuits, devices, systems, methods, techniques, communications channels, etc., that communicate data by using modulated electromagnetic radiation through a non-solid medium. The term does not imply that the associated devices do not contain any wires, although in some embodiments they might not. The term “base station” (BS) is used to describe a wireless device that controls and/or coordinates wireless communications in a network, while the term “subscriber station” (SS) is used to describe one of the other devices in the network whose communications are controlled and/or coordinated by the base station. Different terms may be used by others to describe these functional devices, such as but not limited to the commonly used terms access point (AP), mobile station (MS), STA, etc., but the terms ‘base station’ and ‘subscriber station’ are considered broad enough to encompass these functional devices, regardless of their names.
When a first wireless device makes a new transmission (i.e., not a retransmission of a previously NAK'd transmission) to a second wireless device, the new transmission may include a previously-used ACID that was ACK'd by the second device in its last usage, along with a one-bit AI_SN that has been toggled from its previous value with that same ACID to indicate this is a new transmission. This is the normal way of recycling the limited number of available ACID's for a particular BS-SS pair, and distinguishing new transmissions from retransmissions. If the second device responds to a transmission with a NAK, it expects to receive a retransmission having the same ACID with the same AI_SN value as the original transmission. However, if the second device receives a transmission using the same ACID, but a toggled AI_SN, the second device knows that the first device is using this ACID in a new transmission, so the second device can assume that first device must have incorrectly received the earlier NAK as an ACK. To take advantage of this situation, some embodiments of the invention may select the ACID for the new transmission from the previously-ACK'd transmissions that were likely to have contained such an error. This makes it more likely that the error will be detected without having to wait until expiration of the time limit for retransmission of the data.
FIG. 1 shows a flow diagram of a method of choosing an ACID for a new transmission, according to an embodiment of the invention. For downlink sequences, this process may be performed by the BS, while for uplink sequences, this process may be performed by the SS. In flow diagram 100 , at 110 the device performing this process may create a pool of available ACID's by eliminating any ACID's whose most recent transmission resulted in a NAK from the other device, thus reducing the group of available ACID's to those whose previous use was in a transmission that resulted in an ACK being received. From this reduced group, at 120 the device may select an ACID whose most recent transmission resulted in receiving an ACK under circumstances that make it more likely a NAK was incorrectly received as an ACK.
Several criteria may be used for this determination. For example, if the ACK was received with a low signal-to-noise ratio (SNR), that low SNR could indicate the likelihood of an incorrectly received signal. If the ACK was received with a weak signal, even if the noise was comparatively low, that weak signal could indicate the likelihood of an incorrectly received signal. Other criteria may also be used to determine the likelihood of an incorrectly received signal. In addition, still other criteria may also be used to select an ACID, so that the selected ACID may be likely, but not be the likeliest, of the available ACID's to have been associated with an incorrectly received ACK.
After selecting an ACID to use, at 130 the device may select an AI_SN value that is toggled (i.e., the opposite value) from the AI_SN value that was used with this same ACID in this ACID's previous use. This will identify the transmission as a new transmission. At 140 , the selected ACID and the selected AI_SN may be placed into the new transmission.
FIG. 2 shows a flow diagram of a method of determining that a previously transmitted NAK was received as an ACK by the other device, according to an embodiment of the invention. For downlink sequences, this process may be performed by the SS, while for uplink sequences, this process may be performed by the BS. In flow diagram 200 , at 210 the device may receive a transmission containing a particular ACID and a particular AI_SN. The device may then compare this ACID with the ACID that was contained in a previously received transmission that was NAK'd by this device, and for which a retransmission has not been received. If the ACID is not associated in this manner with a current NAK status, as indicated at 220 , then the transmission may be processed at 260 in the normal manner as a new transmission.
However, if this ACID is associated with a current NAK status, as indicated at 220 , then the AI_SN may be examined at 230 to determine if this transmission was intended to be retransmission. If the AI_SN in the currently-received transmission has the same value that it had with the previous transmission containing this ACID, then the current transmission was intended as a retransmission, and may be processed as such at 240 . However, if the decision at 230 indicates that the AI_SN in the currently-received transmission has the opposite value that it had with the previous transmission containing this ACID, then the current transmission was intended as a new transmission. But since that previous transmission was NAK'd by this device, this particular ACID should only be used for a retransmission. This conflict may be interpreted by this device as an indication that its previous NAK was incorrectly received as an ACK. This determination may result, at 250 , in this device initiating a NAK at its MAC level, using the ARQ protocol. Although such an ARQ NAK might eventually happen anyway (e.g., after a timeout expires without receiving the expected retransmission), the process described in FIG. 2 allows it happen much sooner.
Although an error in a previous communication may be indicated by the determinations at 220 and 230 , the current transmission is still a valid new transmission. So in addition to initiating an ARQ NAK at 250 , the device may also process the current transmission as a new transmission at 260 . Note: in this document, all ACKs and NAKs are assumed to be handled at the PHY level using HARQ protocols, unless the MAC level or ARQ protocol is expressly indicated.
FIGS. 3, 4, 5 and 6 show different scenarios for detection of an incorrectly received ACK, according to various embodiments of the invention. In the downlink sequence of FIG. 3 , the BS may make a transmission Tx1 to the SS. The SS does not receive Tx1 correctly, and therefore transmits a NAK back to the BS. However, due to poor signal quality or other reason the NAK is received by the BS as an ACK. Note: this exchange may have been preceded by one or more Tx1/NAK exchanges in which the NAK was correctly received by the BS, so Tx1 may have been a retransmission (assuming the maximum allowable number of retransmissions was not reached). However, this distinction does not change the pertinent exchanges that are illustrated here. While the SS is waiting for a retransmission of Tx1 (labeled as ReTx1), the BS may think that Tx1 was correctly received by the SS, and BS may therefore clear Tx1 from its PHY-Ievel buffers. Since the BS believes that Tx1 was correctly received by the SS, the BS may place the ACID from Tx1 back into its pool of available ACID's to use for new transmissions.
FIG. 3 assumes the BS now has new data to transmit to the SS, and this new data is indicated as Tx2. To select one of the available ACIDs for the transmission of Tx2, the BS may use certain rules, examples of which were previously described for FIG. 1 . The BS may then place the selected ACID into Tx2, along with a value for AI_SN that indicates this is a new transmission rather than a retransmission. When Tx2 is transmitted by the BS and received by the SS, the use of this particular ACID in a new transmission allows the SS to determine that its previous NAK (associated with the same ACID) must have been received by the BS as an ACK, because if it were received correctly as a NAK, this ACID would only be used now in a retransmission. The SS may then have its MAC level initiate an ARQ NAK for transmission back to the BS, thereby notifying the BS that the earlier Tx1 was not received correctly and needs to be retransmitted.
FIG. 4 is similar to FIG. 3 , but assumes that after transmitting Tx1, the BS has no more data to send to the SS. Since the methods described here require some form of additional transmission so that the SS can compare the ACID in the new transmission with the NAK'd ACID for a previous transmission, two other forms of additional transmission are shown in FIG. 4 . In one embodiment, a MAC layer Control message may be transmitted from the BS to the SS. MAC Control messages are ordinarily used as part of the overall network management procedures. In another embodiment, a Scheduling Grant may be transmitted to the SS to schedule the time/channels for the SS to use in a subsequent communication. As long as the same rules as before are used for selecting the ACID for this MAC Control message or this Scheduling Grant, the SS may use the same analysis to determine whether receiving this ACID in a new transmission indicates that the previous NAK was incorrectly received by the BS as an ACK. Note: as used in this document, the term “new transmission” refers to any transmission between this BS-SS pair that is not a retransmission of a previously NAK'd transmission, regardless of whether the new transmission is made for the purpose of communicating data, performing management functions, scheduling future communications, etc.
FIG. 5 assumes that the NAKs from the SS are correctly received by the BS, but none of the transmission or retransmissions from the BS are correctly received by the SS. In this situation, a limited number of retransmissions may be permitted for this particular transmission Tx1. Once that number of retransmissions is reached, the SS may initiate an ARQ NAK at the MAC level, regardless of whether the last NAK was in error or not.
FIG. 6 shows an uplink sequence, in which the SS makes the initial transmission Tx1, and the BS responds with an ACK or NAK. Although the BS/SS roles are reversed from FIG. 3 , the same corruption of a HARQ NAK to a HARQ ACK can occur. In this embodiment, when the SS receives an ACK, it does not retransmit Tx1. If the ACK was actually a NAK that was incorrectly received as an ACK, then the BS will be waiting for a retransmission that the SS does not intend to send. Since the BS schedules both downlink and uplink transmissions, the BS can schedule the retransmission through a Scheduling Grant. When the SS receives this Scheduling Grant for the retransmission of Tx1 that it did not intend to send, the SS determines that the ACK it received for Tx1 was received in error, and it can retransmit Tx1 (or the first attempt with ReTx1) as ReTx1. If the SS did not clear Tx1 from its buffer when it erroneously received the ACK (as shown), this facilitates retransmission of Tx1 at the PHY level, thus streamlining the process.
FIG. 7 shows a block diagram of a base station and an associated subscriber station, according to an embodiment of the invention. The base station BS and the subscriber station SS each comprise a processor (PROC), a memory (MEM), and a radio (RADIO). The BS 710 is shown with two antennas, while the SS 720 is shown with a single antenna, but either device may have one or any feasible quantity of multiple antennas. Both uplink and downlink data may be wirelessly communicated between the two devices. Although the same labels PROC, MEM, and RADIO are used in each device, this does not imply that one device has an identical processor, memory, or radio as the other device.
The foregoing description is intended to be illustrative and not limiting. Variations will occur to those of skill in the art. Those variations are intended to be included in the various embodiments of the invention, which are limited only by the sope of the following claims.
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In wireless communication networks that use ARQ/HARQ feedback protocols, when a first device receives an apparent HARQ ACK from a second device, the first device may make a new transmission using a HARQ Channel ID whose previous usage was under conditions indicating a likelihood of error in the ACK. When the second device receives the new transmission, the reuse of that HARQ Channel ID in a new transmission rather than a retransmission lets the second device know that its previous NAK transmission was incorrectly received as an ACK.
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CROSS-REFERENCE TO RELATED PATENT APPLICATION
This application claims the benefit of Korean Patent Application No. 10-2009-0059646, filed on Jul. 1, 2009, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an apparatus for inspecting a structure including a heating tube, a tube sheet supporting the heating tube, and a flow distribution baffle, which are installed in a steam generator of a nuclear power plant, and for removing a foreign object, and more particularly, to an apparatus for visually inspecting and removing a foreign object in gaps of a bundle of heating tubes of an upper portion of a tube sheet of a secondary side of a steam generator, in which a detector is inserted into gaps of a bundle of heating tubes of an upper portion of a secondary side of a steam generator so as to inspect sludge or foreign objects, and a foreign object remover removes foreign objects when foreign objects are discovered in the gaps of the heating tubes.
2. Description of the Related Art
Generally, a steam generator is one of main facilities required to produce power from a steam turbine and a power generator in a nuclear power plant.
In detail, a plurality of heating tubes formed in a bundle are disposed in the steam generator. The heating tube performs as a heat exchanger between primary system water containing radioactivity and secondary system water turning a turbine, and separates the primary system water from the secondary system water.
Steam is generated as follows. The primary system water heated while passing through a nuclear reactor flows through a path in the heating tube of the steam generator. The secondary system water provided out of the heating tube contacts an external wall of the heating tube. Thus, heat exchange is performed between the primary system water and the secondary system water. The primary system water flows through the path of the heating tube, and circulates through the nuclear reactor. In addition, the secondary system water is changed to steam.
That is, radioactive water (i.e., the primary system water) with high temperature and pressure flows in the heating tube, and nonradioactive water (i.e., the secondary system water) flows out of the heating tube, wherein a wall of the heating tube is disposed between the primary system water and the secondary system water. Thus, if the heating tube is damaged, the radioactive water (i.e., the primary system water) flowing through the heating tube may be mixed with the nonradioactive water (i.e., the secondary system water) to be contaminated while leaking out of the heating tube, and thus radioactive contamination may occur throughout a space to which steam changed from the nonradioactive water (i.e., the secondary system water) is provided. Accordingly, it is most important to ensure reliability of heating tubes in various operations in a nuclear power plant.
FIG. 1 is a cross-sectional view of a conventional steam generator 10 . FIG. 2A is a front cross-sectional view of the steam generator 10 of FIG. 1 . FIG. 2B is a cross-sectional view for explaining a mechanism of the steam generator 10 of FIG. 1 .
Referring to FIGS. 1 , 2 A and 2 B, the steam generator 10 includes an inlet nozzle 1 into which a reactor coolant of a primary system flows, a heating tube 3 where heat exchange is performed, and an outlet nozzle 5 transferring heat from the reactor coolant flowing into the inlet nozzle 1 to a reactor coolant of a secondary system disposed out of the heating tube 3 . The heating tube 3 is mounted on a tube sheet 4 , and is supported by tube support plates 6 that are vertically arranged at predetermined intervals. A flow distribution baffle 8 shaped like a doughnut plate is installed between the lowest tube support plate 6 and the tube sheet 4 so as to support the heating tube 3 . The heating tube 3 , and the tube support plate 6 that are vertically arranged at predetermined intervals so as to support the heating tube 3 are coupled to a wrapper 20 of which a lower portion is opened and of which an upper portion has a steam outlet 21 . Water is provided into the lower portion of the wrapper 20 along an inner wall of an external housing 2 . The provided water generates steam by the heating tube 3 , and then the steam is discharged upwards.
The steam generator 10 having the above-described structure generates heat as follows: the reactor coolant of the primary system flows through the inlet nozzle 1 in the heating tubes 3 , passes through the outlet nozzle 5 , and transfers heat to the reactor coolant of the secondary system disposed out of the heating tubes 3 , thereby generating steam.
A portion of the steam generator 10 where a reactor coolant flows is referred to as a primary side, and a portion of the steam generator 10 where water is fed and steam flows is referred to as a secondary side. The secondary side of the steam generator 10 includes a main steam system, a turbine system, a condensate water system, and a feed-water system.
Thus, steam generated by the secondary side of the steam generator 10 moves through a main steam tube, and turns a turbine.
However, conventionally, when the steam generator 10 generates steam, although secondary water is filtered and chemically-treated so as to be provided to the secondary side, the secondary water accompanied with foreign objects and sludge which are generated due to various reasons while circulating in the heating tube 3 flows into the steam generator 10 . Thus, the foreign objects and sludge may be deposited onto the tube sheet 4 , the tube support plate 6 , the flow distribution baffle 8 , etc. or may be stuck to an external wall of the heating tube 3 , thereby reducing heating efficiency of the steam generator 10 or damaging the steam generator 10 .
That is, the steam generator 10 has a structure in which several thousands of U-shaped heating tubes 3 are disposed in a bundle type, both ends of the heating tube 3 are fixed to the tube sheet 4 , and the heating tube 3 are supported by the tube support plates 6 that are vertically arranged so as to have seven steps at an interval of about 1 m up to an upper portion of the heating tube 3 , as illustrated in FIG. 2 . Impurities as scale generated due to various reasons when driving soft water flows are stuck to a surface of the heating tube 3 , thereby reducing heat-exchange efficiencies. The impurities are deposited as sludge and are gradually solidified between the heating tube 3 and the tube support plate 6 , and thus denting occurs between the tube support plate 6 and the heating tube 3 , thereby damaging the heating tube 3 . Accordingly, it is necessary to remove scale stuck to the surface of the heating tube 3 and sludge deposited on the tube support plate 6 in order to ensure efficiencies of the steam generator 10 and reliability of the heating tube 3 .
To achieve this, a small-sized endoscope camera has been used to check states of the flow distribution baffle 8 , the heating tube 3 and the tube sheet 4 .
However, an operator needs to manually push the endoscope camera into a gap of a heating tube through a guide tube. Since the endoscope camera does not include an element for supporting the endoscope camera, the endoscope camera cannot find out and check a desired position. In addition, since a steam generator is surrounded by high radioactivity, an operator may be exposed to radioactivity, and therefore it is difficult to visually inspect or remove foreign objects.
SUMMARY OF THE INVENTION
The present invention provides an apparatus for visually inspecting and removing a foreign object in gaps of a bundle of heating tubes of an upper portion of a tube sheet of a secondary side of a steam generator, in which a detector is inserted into a gap of a bundle of heating tubes of an upper portion of a secondary side of a steam generator so as to inspect sludge or foreign objects, and a foreign object remover removes foreign objects when foreign objects are discovered in the gap of the heating tube.
Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the presented embodiments.
According to an aspect of the present invention, there is provided an apparatus for visually inspecting and removing a foreign object in gaps of a bundle of heating tubes of an upper portion of a tube sheet of a secondary side of a steam generator, the apparatus including: a mounting fixture fixed to a flange surface of a hand hole of the steam generator by a bolt; a guide rail of which one side is fixed to the mounting fixture, wherein a first end of the guide rail is coupled to a center stay rod disposed at a central portion of the steam generator, and a second end of the guide rail is coupled to a driver; a detector coupled to a lower end of the guide rail so as to slide on the lower end of the guide rail, inserted into the steam generator by a moving belt, and visually inspecting and removing a foreign object; the driver supplying power to the detector, wherein one side of the driver is coupled to the guide rail, and is simultaneously coupled to a rail supporter of the mounting fixture; and local and remote controllers adjacent to the steam generator and controlling the mounting fixture, the detector and the driver.
The mounting fixture may include a flange having four bolts installed therein so as to fix the mounting fixture to the flange surface of the hand hole of the steam generator; a panning plate of which a front surface is coupled to the flange so as to slide in a lateral direction of the flange; a tilting lever hinged to a rear surface of the panning plate so as to optionally tilt; the rail supporter coupled to the tilting lever and supporting the guide rail; and two cable guides disposed on a rear surface of the tilting lever so as to stably accommodate cables from the detector therein and to prevent the cables from being entangled and damaged.
The flange may include screw holes formed therein into which the four blots are inserted, respectively, so as to fix the mounting fixture to the flange surface of the steam generator, wherein the screw holes each having a circular shape may be formed in four edges of flange, and the mounting fixture may roll by optionally rotating the flange and then coupling the four bolts to the screw holes, respectively.
The flange and the panning plate may include respective connectors, which have corresponding shapes to each other and are formed on surfaces of the flange and the panning plate, which come in contact with each other, the flange and the panning plate may be coupled by sliding the flange and the panning plate on each other, and the panning plate may move right and left by a control pin disposed at both sides of the flange.
The tilting lever may include a knuckle joint having a first end in contact with the panning plate, and a second end with a screw thread formed thereon; and a control bolt coupled to the screw thread formed on the second end of the knuckle joint, wherein the tilting lever may tilt by a manner in which the control bolt rotates around the knuckle joint to push the knuckle joint.
The rail supporter may include a horizontal and vertical level gage installed thereon, wherein the horizontal and vertical level gage checks a change in an angle of right and left rotation of the mounting fixture, and a change in an angle of horizontal and vertical movement of the mounting fixture.
The guide rail may function as a guide of the detector, and may include a plurality of rod-shaped guide rods that are separately coupled to each other.
The guide rail may include a first guide rod including a gripper that is disposed at a first end of the first guide rod so as to support and fix the center stay rod of the steam generator to the guide rail by tightening the center stay rod, and a connecting block having a screw hole and formed at a second end of the first guide rod; a second guide rod including a clamping bolt that is disposed at a first end of the second guide rod and is screwed to the screw hole formed in the connecting block so as to be coupled to the first guide rod, and a connecting block disposed at a second end of the second guide rod and having a screw hole formed in the connecting block; and a third guide rod including a clamping bolt that is disposed at a first end of the third guide rod and is screwed to the screw hole formed in the connecting bolt so as to be coupled to the second guide rod, wherein the driver is coupled to a second end of the third guide rod.
The apparatus may further include a guiding groove formed in a lower portion of the guide rail, wherein the moving belt is inserted into the guiding groove.
The detector may include a detecting portion visually-inspecting and removing sludge or a foreign object in the steam generator, including a photographing sheet and a foreign object remover, and rotating right and left; a detection driving portion supplying power to the detector so as to drive the detecting portion; and a bracket portion connecting the detecting portion to the detection driving portion so as to be coupled to the guide rail.
The detecting portion may include a body installed in front of the bracket portion and including a bobbin disposed in the body; a steel belt disposed in the body and having a first end wound on the bobbin; the photographing sheet coupled to a second end of the steel belt and having an end at which a charge-coupled device (CCD) sensor and a light emitting display device (LED) are installed so as to generate a image signal of a visual inspection; and the foreign object remover installed adjacent to the photographing sheet so as to remove a foreign object checked by the photographing sheet.
The steel belt may include a plurality of coupling holes formed in a center of the steel belt in a longitudinal direction of the steel belt at predetermined intervals, and the steel belt may be wound into the body according to rotation of the bobbin and an intermittent gear having a plurality of protrusions formed on an outer circumference surface of the intermittent gear, wherein the intermittent gear and the bobbin are disposed in the body.
The detection driving portion may include a housing installed at a rear surface of the bracket portion, transferring a driving force to the detecting portion, and coupled to the bracket portion; a tilting motor installed in the housing and supplying power to the detecting portion so as to rotate the detecting portion towards both sides of the detecting portion; and a feeding motor supplying power so that the photographing sheet and the foreign object remover of the detecting portion are extended or reduced out of the body.
The driver may include a main housing having an end coupled to the guide rail and simultaneously coupled to the rail supporter of the mounting fixture, and including a bobbin disposed in the main housing and rotated by a plurality of gears; the moving having a first end wound on the bobbin and a second end coupled to the bracket portion of the detector so as to move along the guide rail; and a driving motor rotating the bobbin disposed in the main housing so that the moving belt is wound or loosened and the detector is moved.
The main housing may include a pinion gear engaged to an intermittent gear having a plurality of protrusions formed on an outer circumference surface of the intermittent gear, the moving belt may include a plurality of through holes formed therein in a longitudinal direction at predetermined intervals, and the plurality of protrusions of the intermittent gear engaged to the pinion gear may be inserted into the plurality of through holes so that the moving belt is wound or loosened on the bobbin.
The apparatus may further include a roller disposed in the main housing and pressurizing the moving belt downwards so that the plurality of protrusions of the intermittent gear engaged to the pinion gear are correctly inserted into the plurality of through holes of the moving belt.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other features and advantages of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings in which:
FIG. 1 is a cross-sectional view of a conventional steam generator;
FIG. 2A is a front cross-sectional view of the steam generator of FIG. 1 ;
FIG. 2B is a cross-sectional view for explaining a mechanism of the steam generator of FIG. 1 ;
FIG. 3 is a lateral cross-sectional view for explaining a case where an apparatus for visually inspecting and removing a foreign object in gaps of a bundle of heating tubes of an upper portion of a tube sheet of a secondary side of a steam generator is installed, according to an embodiment of the present invention;
FIG. 4 is a cross-sectional view of FIG. 3 ;
FIG. 5 is a schematic perspective view of an apparatus for visually inspecting and removing a foreign object in gaps of a bundle of heating tubes of an upper portion of a tube sheet of a secondary side of a steam generator, according to an embodiment of the present invention;
FIG. 6 is a cross-sectional view of a mounting fixture of an apparatus for visually inspecting and removing a foreign object in gaps of a bundle of heating tubes of an upper portion of a tube sheet of a secondary side of a steam generator, according to an embodiment of the present invention;
FIG. 7 is an exploded perspective view of FIG. 6 ;
FIGS. 8A through 8C are cross-sectional views for explaining movement of the mounting fixture of FIG. 6 , according to an embodiment of the present invention;
FIG. 9 is a schematic perspective view of a guide rail of an apparatus for visually inspecting and removing a foreign object in gaps of a bundle of heating tubes of an upper portion of a tube sheet of a secondary side of a steam generator, according to an embodiment of the present invention;
FIG. 10 is an exploded perspective view of the guide rail of FIG. 9 ;
FIG. 11 is a perspective view of a detector of an apparatus for visually inspecting and removing a foreign object in gaps of a bundle of heating tubes of an upper portion of a tube sheet of a secondary side of a steam generator, according to an embodiment of the present invention;
FIG. 12 is an exploded perspective view of the detector of FIG. 11 ;
FIG. 13 is a schematic perspective view of a configuration of gears of a detecting portion of a detector of an apparatus for visually inspecting and removing a foreign object in gaps of a bundle of heating tubes of an upper portion of a tube sheet of a secondary side of a steam generator, according to an embodiment of the present invention;
FIG. 14 is a front view for explaining a case where the detecting portion of the detector of FIG. 11 moves right and left, according to an embodiment of the present invention;
FIG. 15 is a perspective view for explaining a case where a foreign object remover is inserted into a guide rail, according to an embodiment of the present invention;
FIG. 16 is a reference diagram for explaining a case where the foreign object remover of FIG. 15 is installed, according to an embodiment of the present invention;
FIG. 17 is a perspective view of a driver, according to an embodiment of the present invention;
FIG. 18 is an exploded perspective view of the driver of FIG. 17 ;
FIG. 19 is a reference diagram for explaining a case where a moving belt of a driver is inserted into a guide rail, according to an embodiment of the present invention; and
FIG. 20 is a diagram for explaining a case where an apparatus for visually inspecting and removing a foreign object in gaps of a bundle of heating tubes of an upper portion of a tube sheet of a secondary side of a steam generator is installed at a steam generator, according to an embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an apparatus for visually inspecting and removing a foreign object in gaps of a bundle of heating tubes of an upper portion of a tube sheet of a secondary side of a steam generator will be described with regard to exemplary embodiments of the invention with reference to the attached drawings.
FIG. 3 is a lateral cross-sectional view for explaining a case where an apparatus for visually inspecting and removing a foreign object in gaps of a bundle of heating tubes of an upper portion of a tube sheet of a secondary side of a steam generator is installed, according to an embodiment of the present invention. FIG. 4 is a cross-sectional view of FIG. 3 . FIG. 5 is a schematic perspective view of an apparatus for visually inspecting and removing a foreign object in gaps of a bundle of heating tubes of an upper portion of a tube sheet of a secondary side of a steam generator, according to an embodiment of the present invention. FIG. 6 is a cross-sectional view of a mounting fixture 110 of an apparatus for visually inspecting and removing a foreign object in gaps of a bundle of heating tubes of an upper portion of a tube sheet of a secondary side of a steam generator, according to an embodiment of the present invention. FIG. 7 is an exploded perspective view of FIG. 6 . FIGS. 8A through 8C are cross-sectional views for explaining movement of the mounting fixture 110 of FIG. 6 , according to an embodiment of the present invention.
Referring to FIGS. 1 through 8C , the apparatus for visually inspecting and removing a foreign object in gaps of a bundle of heating tubes of an upper portion of a tube sheet of a secondary side of a steam generator is installed in a hand hole ‘H’ of an upper portion of one side of Westinghouse F-type steam generator disposed in an accommodation room, and includes the mounting fixture 110 , a guide rail 120 , a detector 130 , a driver 140 , a foreign object remover 150 , a local controller 160 , and a remote controller 170 .
As illustrated in FIG. 3 , the mounting fixture 110 is fixed to a flange surface of the hand hole ‘H’ by bolts ‘S’, and is used to stably fix and support the guide rail 120 . As illustrated in FIGS. 6 and 7 , the mounting fixture 110 includes a flange 111 having four bolts ‘S’ so as to fix the mounting fixture 110 to the flange surface of the hand hole ‘H’, a panning plate 112 whose front surface is coupled to the flange 111 so as to slide in a lateral direction of the flange 111 , a tilting lever 113 hinged to a rear surface of the panning plate 112 so as to optionally tilt, a rail supporter 114 coupled to the tilting lever 113 so as to support the guide rail 120 that will be described, and two cable guides 115 disposed on a rear surface of the tilting lever 113 so as to stably accommodate cables from the detector 130 therein and to prevent the cables from the detector 130 from being entangled and damaged.
The mounting fixture 110 having the above-described structure may stably support the guide rail 120 so that the detector 130 may stably move along the guide rail 120 .
In detail, the mounting fixture 110 may finely adjust a detection angle of the detector 130 by finely adjusting an angle of the guide rail 120 . With regard to the mounting fixture 10 , four screw holes 110 a each having a circular shape, to which the bolts ‘S’ are inserted, are formed in four edges of the flange 111 , respectively, so that the mounting fixture 10 is coupled to a steam generator 10 . Thus, the mounting fixture 110 may roll in a direction indicated by an arrow of FIG. 8A by optionally rotating the flange 111 and then coupling the bolts ‘S’ to the screw holes 111 a . The flange 111 and the panning plate 112 includes connectors 111 b and 112 a , respectively, which have corresponding shapes to each other and are formed on surfaces of the flange 111 and the panning plate 112 , which come in contact with each other, as illustrated in FIG. 7 . In addition, the flange 111 and the panning plate 112 are coupled by sliding them onto each other by the connectors 111 b and 112 a . The panning plate 112 may be moved in a direction (a horizontal direction) indicated by an arrow of FIG. 8B by control pins 116 disposed at both sides of the flange 111 .
As illustrated in FIG. 7 , the tilting lever 113 hinged to the rear surface of the panning plate 112 is coupled to hinge blocks 112 b screwed to a lower portion of the panning plate 112 by pins 112 c so as to optionally tilt. In this regard, the tilting lever 113 tilting with respect to the panning plate 112 includes a knuckle joint 117 having a first end in contact with the panning plate 112 and a second end having a screw thread formed thereon so as to optionally tilt with respect to the panning plate 112 , and a control bolt 118 coupled to the screw thread formed on the second end of the knuckle joint 117 . The control bolt 118 rotates around the knuckle joint 117 to push the knuckle joint 117 , and then the tilting lever 113 may tilt in a direction indicated by an arrow of FIG. 8C .
In addition, the tilting lever 113 may include a pair of brackets 113 a so that lateral surface portions of the rail supporter 114 may be supported by the brackets 113 a . At this time, the rail supporter 114 may be coupled to the flange 111 , the panning plate 112 and the tilting lever 113 so as to pass through the flange 111 , the panning plate 112 and the tilting lever 113 in a horizontal direction. The guide rail 120 , which will be described later, may be fixed to a lower portion of the rail supporter 114 .
As illustrated in FIG. 3 , the mounting fixture 110 having the above-described structure is stably fixed to the flange surface of the hand hole ‘H’ by bolts ‘S’, the guide rail 120 is coupled to the rail supporter 114 , and then the detector 130 , which will be described later, is inserted into the steam generator 10 along the guide rail 120 . By this structure, sludge or foreign objects may be inspected.
At this time, the mounting fixture 110 may optionally roll due to the screw holes 111 a of the flange 111 . Simultaneously, the panning plate 112 may pan with respect to the flange 111 by coupling the connectors 111 b and 112 a , which have corresponding shapes to each other, by using a dovetail coupling method in which the connectors 111 b and 112 a are coupled by sliding them onto each other. In addition, simultaneously, the tilting lever 113 may tilt with respect to the panning plate 112 by hinging the panning plate 112 to the tilting lever 113 . Thus, the rail supporter 114 coupled to the tilting lever 113 may rotate around the center of the hand hole ‘H’ right and left by about 10 to about 15 degrees, and may be finely adjusted in horizontal and vertical directions.
In addition, a horizontal and vertical level gage 119 may be installed on the rail supporter 114 so as to check a change in an angle of right and left rotation of the mounting fixture 110 , and a change in an angle of horizontal and vertical movement of the mounting fixture 110 , and thus a change in a movement angle of the mounting fixture 110 may be easily checked.
FIG. 9 is a schematic perspective view of a guide rail 120 of an apparatus for visually inspecting and removing a foreign object in gaps of a bundle of heating tubes of an upper portion of a tube sheet of a secondary side of a steam generator, according to an embodiment of the present invention. FIG. 10 is an exploded perspective view of the guide rail 120 of FIG. 9 .
A first end of the guide rail 120 is coupled to a center stay rod ‘C’ disposed at a central portion of the steam generator 10 , and a second end of the guide rail 120 is coupled to the driver 140 that will be described later. The second end coupled to the driver 140 is fixed to the rail supporter 114 of the mounting fixture 110 , thereby guiding the detector 130 that will be described later into the steam generator 10 (into the gap of a bundle of heating tubes).
As illustrated in FIG. 9 , the guide rail 120 includes a plurality of rod-shaped rods with a predetermined length, wherein the rods may be separately coupled, and thus the length of the guide rail 120 may be extended or reduced. According to the present embodiment, the guide rail 120 includes three guide rods 121 , 122 and 123 .
In detail, as illustrated in FIG. 10 , the guide rail 120 includes a first guide rod 121 , a second guide rod 122 and a third guide rod 123 . The first guide rod 121 includes a gripper 124 that is disposed at a first end of the first guide rod 121 so as to support and fix the center stay rod ‘C’ by tightening the center stay rod ‘C’, and a connecting block 125 that is formed at a second end of the first guide rod 121 and has a screw hole 125 a so as to be coupled to the second guide rod 122 .
The second guide rod 122 includes a clamping bolt 126 that is formed at a first end of the second guide rod 122 and is screwed to the screw hole 125 a formed in the connecting block 125 so as to be coupled to the first guide rod 121 , and a connecting block 125 that is formed at a second end of the second guide rod 122 and includes a screw hole 125 a formed at the center of center of the connecting block 125 so as to be coupled to the third guide rod 123 , like in the first guide rod 121 .
In addition, the third guide rod 123 includes a clamping bolt 126 that is formed at a first end of the third guide rod 123 and is screwed to the screw hole 125 a formed in the connecting block 125 of the second guide rod 122 , like in the second guide rod 122 , and the driver 140 supplying power is coupled to a second end of the third guide rod 123 .
According to the present embodiment, the first, second and third guide rods 121 , 122 and 123 , that is, three guide rods constitute the guide rail. Alternatively, separate guide rods may be further used to extend or reduce the length of the guide rail 120 , if necessary.
FIG. 11 is a perspective view of a detector 130 of an apparatus for visually inspecting and removing a foreign object in gaps of a bundle of heating tubes of an upper portion of a tube sheet of a secondary side of a steam generator, according to an embodiment of the present invention. FIG. 12 is an exploded perspective view of the detector 130 of FIG. 11 . FIG. 13 is a schematic perspective view of a configuration of gears of a detecting portion 132 of a detector 130 of an apparatus for visually inspecting and removing a foreign object in gaps of a bundle of heating tubes of an upper portion of a tube sheet of a secondary side of a steam generator, according to an embodiment of the present invention. FIG. 14 is a front view for explaining a case where the detecting portion 132 of the detector 130 of FIG. 11 moves right and left, according to an embodiment of the present invention. FIG. 15 is a perspective view for explaining a case where a foreign object remover 132 d is inserted into a guide rail 120 , according to an embodiment of the present invention. FIG. 16 is a reference diagram for explaining a case where the foreign object remover 132 d of FIG. 15 is installed, according to an embodiment of the present invention.
As illustrated in FIG. 5 , the detector 130 may be coupled to a lower end of the guide rail 120 so as to slide onto the lower end of the guide rail 120 , and may move forwards and backwards by the driver 140 that will be described later. Thus, the detector 130 is inserted into the steam generator 10 along the guide rail 120 , and thus may visually inspect foreign objects, and may simultaneously remove foreign objects.
Referring to FIG. 11 , the detector 130 may visually inspect or remove sludge or foreign objects. The detector 130 may include the detecting portion 132 rotating right and left, a detection driving portion 134 supplying power to the detecting portion 132 so as to drive the detecting portion 132 , and a bracket portion 136 connecting the detecting portion 132 to the detection driving portion 134 so as to be coupled to the guide rail 120 .
The detecting portion 132 inserted into gaps of the heating tubes in the steam generator 10 is installed in front of the bracket portion 136 so as to inspect or remove sludge or foreign objects. As illustrated in FIGS. 12 and 13 , the detecting portion 132 includes a body 132 a coupled to the bracket portion 136 and having a bobbin ‘b’ formed in the body 132 a , a steel belt 132 b disposed in the body 132 a and having a first end wound on the bobbin ‘b’, a photographing sheet 132 c coupled to a second end of the steel belt 132 b and having an end at which a charge-coupled device (CCD) sensor and a light emitting display device (LED) are installed so as to generate a image signal of a visual inspection, and the foreign object remover 132 d installed adjacent to the photographing sheet 132 c so as to remove sludge and foreign objects, which are checked by the photographing sheet 132 c.
As illustrated in FIG. 13 , the body 132 a is configured so that a plurality of gears are engaged to each other, wherein the bobbin ‘b’ rotates as the gears rotate. In addition, the steel belt 132 b is configured to be wound or loosened by a clockwise or counter clockwise rotation from a state where an end of the steel belt 132 b is wound on the bobbin ‘b’. The body 132 a includes an intermittent gear ‘g’ having a plurality of protrusions 132 a - 1 formed on a central portion thereof so that the steel belt 132 b may be smoothly wound on the bobbin ‘b’. The steel belt 132 b includes a coupling hole 132 b - 1 into which the protrusions 132 a - 1 formed on the intermittent gear ‘g’ are inserted so that the steel belt 132 b may be wound or loosened on the bobbin ‘b’ according to rotation of the intermittent gear ‘g’. In addition, the steel belt 132 b may be flexible so as to be easily wound or loosened on the bobbin ‘b’.
The foreign object remover 132 d is installed adjacent to and behind the photographing sheet 132 c , and removes sludge or foreign objects detected by the photographing sheet 132 c . In addition, the foreign object remover 132 d includes a wire 132 d - 1 extended into or out of the body 132 a of the detecting portion 132 , and a foreign object removing tool 132 d - 2 installed at an end of the wire 132 d - 1 and having various shapes of a tong, a magnet, a ring, and the like.
As illustrated in FIGS. 15 and 16 , an end of the foreign object remover 132 d is inserted into a foreign object remover hole 128 formed in the guide rail 120 , and passes along a foreign object remover groove 128 a of the guide rail 120 , which is manually performed by an operator when foreign objects are discovered. Then, as illustrated in FIG. 12 , the wire 132 d - 1 is extended out of the detection driving portion 134 , and then passes through a flexible tube 138 that will be described. Then, the wire 132 d - 1 together with the detecting portion 132 is inserted into the gaps of the heating tubes along a groove formed in the body 132 a.
The detection driving portion 134 includes a housing 134 a installed at a rear surface of the bracket portion 136 , transferring a driving force to the detecting portion 132 and coupled to the bracket portion 136 , a tilting motor 134 c installed in the housing 134 a and supplying power to the detecting portion 132 so as to rotate the detecting portion 132 towards both sides of the detecting portion 132 , as illustrated in FIG. 14 , and a feeding motor 134 b supplying power so that the photographing sheet 132 c of the detecting portion 132 may be extended or reduced out of the body 132 a.
Although not illustrated, the tilting motor 134 c rotates the body 132 a in directions of both sides thereof through a spindle (not shown) disposed in the body 132 a , and the feeding motor 134 b coupled to a bevel gear (not shown) disposed in the body 132 a rotates the intermittent gear ‘g’ and the bobbin ‘b’ so that the steel belt 132 b may be wound into the body 132 a.
The bracket portion 136 connecting the detecting portion 132 to the detection driving portion 134 may be formed so that an upper portion of the bracket portion 136 is coupled to a lower end of the guide rail 120 , as illustrated in FIG. 14 . In addition, the bracket portion 136 may be formed so as to slide on the guide rail 120 . As illustrated in FIG. 12 , the flexible tube 138 may be wound on the wire 132 d - 1 of the foreign object remover 132 d so as to function as a guide used for the detecting portion 132 to smoothly rotate with respect to lateral surfaces of the bracket portion 136 , and for the foreign object remover 132 d to be smoothly extended in or out of the detecting portion 132 in a rotating direction of the detecting portion 132 .
FIG. 17 is a perspective view of the driver 140 , according to an embodiment of the present invention. FIG. 18 is an exploded perspective view of the driver 140 of FIG. 17 . FIG. 19 is a reference diagram for explaining a case where a moving belt 144 of the driver 140 is inserted into the guide rail 120 , according to an embodiment of the present invention.
As illustrated in FIGS. 17 and 18 , the driver 140 may be coupled to an end of the guide rail 120 , for example, an end of the third guide rod 123 to which the mounting fixture 110 is coupled, may supply power to the detecting portion 132 so that the detecting portion 132 may be moved along the guide rail 120 into the steam generator 10 , and may include a main housing 142 , the moving belt 144 , and a driving motor 146 .
As illustrated in FIG. 17 , an end of the main housing 142 is coupled to the guide rail 120 , and simultaneously may be coupled to the rail supporter 114 of the mounting fixture 110 . As illustrated in FIG. 18 , the main housing 142 includes an intermittent gear 142 c - 1 engaged to a plurality of gears and having a plurality of protrusions formed on an outer circumference surface of the intermittent gear 142 c - 1 , wherein the intermittent gear 142 c - 1 is engaged to a pinion gear 142 c so as to drive the moving belt 144 .
A first end of the moving belt 144 is wound on the bobbin ‘b’, and a second end of the moving belt 144 is coupled to the bracket portion 136 of the detector 130 so that the detector 130 may move along the guide rail 120 . That is, as illustrated in FIG. 19 , the first end of the moving belt 144 may be wound on the bobbin ‘b’, and the second end of the moving belt 144 may be coupled to the detector 130 through a guiding groove 127 formed in a lower portion of the guide rail 120 so that the detector 130 may move by as much as a length by which the moving belt 144 wound on the bobbin ‘b’ is loosened.
The driving motor 146 is engaged to a plurality of gears disposed in the main housing 142 so that the gears may be engaged to each other and may rotate as the driving motor 146 rotates. Thus, the protrusions of the intermittent gear 142 c - 1 engaged to the pinion gear 142 c are coupled into a plurality of through holes 145 formed in the moving belt 144 so as to drive the moving belt 144 , and thus the bobbin ‘b’ rotates so that the moving belt 144 may be wound or loosened on the bobbin ‘b’.
In detail, with regard to the driver 140 , the bobbin ‘b’ on which the moving belt 144 is wound, and a plurality of gears connected to a motor are disposed in the main housing 142 , and thus the moving belt 144 is driven so as to rotate the bobbin ‘b’ clockwise and counter clockwise, as illustrated in FIG. 18 . In addition, the gears are coupled to the driving motor 146 that are disposed at one side of the gears. As the driving motor 146 rotates, a gear 142 c rotates. Then, the intermittent gear 142 c - 1 engaged to the gear 142 c rotates so that the moving belt 144 wound on the bobbin ‘b’ may be wound or loosened so as to move the detector 130 .
The gears installed in the main housing 142 includes a bevel gear 142 a engaged to the driving motor 146 , and the pinion gear 142 c engaged to the bevel gear 142 a through a needle gear 142 b and engaged to the intermittent gear 142 c - 1 having a plurality of protrusions formed on an outer circumference surface of the intermittent gear 142 c - 1 . When the driving motor 146 supplies power, the bevel gear 142 a rotates, and therefore the pinion gear 142 c engaged to the bevel gear 142 a rotates so that the moving belt 144 may be wound on the bobbin ‘b’.
As illustrated in FIG. 18 , with regard to the moving belt 144 , the through holes 145 are formed in a longitudinal direction of the moving belt 144 at predetermined intervals. intermittent gear 142 c - 1 of the pinion gear 142 c may be inserted into the through holes 145 so that the moving belt 144 may be wound or loosened on the bobbin ‘b’ according to the rotation of the pinion gear 142 c . A roller 147 pressurizing the moving belt 144 downwards is installed at an upper side of the pinion gear 142 c so that the intermittent gear 142 c - 1 of the pinion gear 142 c may be correctly inserted into the through holes 145 of the moving belt 144 .
A handle 148 is installed at one side of the main housing 142 of the driver 140 so that a worker may manually wind or loosen the moving belt 144 on the bobbin ‘b’. In an emergency, the bobbin ‘b’ may be rotated by manually rotating the handle 148 , and thus the detector 130 may be moved.
FIG. 20 is a diagram for explaining a case where an apparatus for visually inspecting and removing a foreign object in gaps of a bundle of heating tubes of an upper portion of a tube sheet of a secondary side of a steam generator is installed at a steam generator 10 , according to an embodiment of the present invention.
A local controller 150 is installed around the steam generator 10 , and controls the mounting fixture 110 , the guide rail 120 , the detector 130 , and the driver 140 . The local controller 150 includes a monitor and a control panel. A remote controller 160 is positioned in an operating room remote from the steam generator 10 in order to avoid radioactivity from the steam generator 10 . In addition, the remote controller 10 may perform automatic control using a special operating program, in addition to the same function as that of the local controller 150 , and may record and edit visual inspection data. The local controller 150 and the remote controller 160 have general structures, and thus their detailed description will not be given here.
The apparatus for visually inspecting and removing a foreign object in gaps of a bundle of heating tubes of an upper portion of a tube sheet of a secondary side of a steam generator may operate as follows.
First, the mounting fixture 110 is installed on a flange surface of the hand hole ‘H’ of the steam generator 10 .
The guide rail 120 on which the detector 130 and the driver 140 are previously mounted is coupled to the mounting fixture 110 . Then, a first end of the guide rail 120 is fixed to the center stay rod ‘C’ installed at the center of the steam generator 10 by the gripper 124 that is disposed at the first end of the guide rail 120 . At this time, the mounting fixture 110 is finely adjusted in horizontal and vertical directions by the control pins 116 , a control bolt 118 , and the like of the mounting fixture 110 .
Then, a cable connected to the driver 140 is extended so as to connect the driver 140 to the local controller 150 installed adjacent to the steam generator 10 and the remote controller 160 installed out of a container, and thus foreign objects may be visually inspected and may be removed.
After the apparatus for visually inspecting and removing foreign object in gaps of an upper portion of a bundle of a tube sheet of a secondary side of a steam generator is installed, electricity is supplied to the driver 140 through the local controller 150 and the remote controller 160 so as to loosen the moving belt 144 wound on the bobbin ‘b’, and thus the detector 130 may be inserted into the steam generator 10 through the guide rail 120 .
The body 132 a of the detector 130 inserted into the steam generator 10 is rotated by the detection driving portion 134 in a desired direction, and then the bobbin ‘b’ and the intermittent gear ‘g’ may rotate so that the steel belt 132 b is extended out of the body 132 a . At this time, while the photographing sheet 132 c is installed at an end of the steel belt 132 b , the gap of the heating tube is inspected through a CCD camera installed at the photographing sheet 132 c , and an image signal of this inspection is transmitted to the remote controller 160 .
When foreign objects are discovered in the gap of the heating tube, a worker inserts the foreign object remover 132 d installed on the detector 130 into the gap of the heating tube through the body 132 a of the detecting portion 132 .
According to the present invention, an apparatus for visually inspecting and removing a foreign object in gaps of a bundle of heating tubes of an upper portion of a tube sheet of a secondary side of a steam generator may visually inspect sludge and foreign objects in the gap of the heating tube disposed on the upper portion of the tube sheet of the secondary side of the steam generator, and simultaneously may remove foreign objects when foreign objects are discovered in the gap of the heating tube.
By performing an operation under high radioactivity by remote control, the amount of radioactivity exposed to a worker may be significantly reduced.
As described above, according to the present invention, although a technology used in an apparatus for visually inspecting and removing a foreign object in gaps of a bundle of heating tubes of an upper portion of a tube sheet of a secondary side of a steam generator is very simple, technological effects thereof is excellent.
Accordingly, according to the present invention, an apparatus for visually inspecting and removing a foreign object in gaps of a bundle of heating tubes of an upper portion of a tube sheet of a secondary side of a steam generator may visually inspect and simultaneously remove foreign objects effectively by inserting a detector visually-inspecting and optionally-removing foreign objects into the steam generator through a hand hole connected to an upper bundle of a secondary side of the steam generator.
In addition, due to a mounting fixture, a guide rail may be finely adjusted and stably supported in horizontal and vertical directions, and may be stably supported.
While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims.
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Provided is an apparatus for inspecting a structure including a heating tube, a tube sheet supporting the heating tube, and a flow distribution baffle, which are installed in a steam generator of a nuclear power plant, and more particularly, an apparatus for visually inspecting and removing a foreign object in gaps of a bundle of heating tubes of an upper portion of a tube sheet of a secondary side of a steam generator, in which a detector is inserted into gaps of a bundle of heating tubes of an upper portion of a secondary side of a steam generator so as to inspect sludge or foreign objects, and a foreign object remover removes foreign objects when foreign objects are discovered in the gaps of the heating tubes.
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FIELD OF THE INVENTION
The present invention is directed to a method for producing polyethylene terephthalate fibers with reduced flammability for the manufacture of textile articles, more specifically it is directed to the addition of a polyalkylene glycol phosphate ester to the polycondensation reaction for the manufacture of polyethylene terephthalate.
BACKGROUND OF THE INVENTION
The main approaches to reduce the flammability of thermoplastic polyesters are melt additives, topical finish treatments, and copolymerization with flame resistant monomers. Melt additives generally include halogenated organic compounds with high levels of bromine or chlorine. A second component when halogenated compounds are employed is antimony trioxide (Sb 2 O 3 ). Other popular elements found in melt additives are phosphorus, molybdenum and nitrogen. Finish treatments generally require high add-on levels, and many of these lack the durability to cleaning procedures required for polyester fabrics such as mattress ticking, apparel, upholstery and drapery.
Phosphorus compounds are widely used to reduce the flammability of thermoplastic polymers. For example U.S. Pat. Nos. 3,987,008; 4,203,888; 4,517,355; and 4,940,772 disclose a broad variety of organic phosphor compounds in thermoplastic polyesters.
U.S. Pat. No. 3,987,008 discloses a polyphosphonate with arylene and haloarylene groups. U.S. Pat. No. 4,203,888 discloses an aryl diphosphate.
One disadvantage of these phosphorus compounds is that they are inert additives which build a separate phase in the thermoplastic polyesters with negative influence of the fiber properties like dyeability.
U.S. Pat. No. 4,517,355 describes a linear polyester, which contains a phosphinic acid derivative bonded in the macromolecule.
U.S. Pat. No. 4,940,772 describes a process for producing a flame resistant polyester by copolymerizing a polyester with an unsaturated compound and reacting this copolyester with a specific phosphorus compound.
An object of the present invention was to provide polyethylene terephthalate with reduced flammability and simultaneous excellent physical fiber properties.
Another object was to improve deep dyeability of polyethylene terepthalate fibers.
Another object was to provide a method for producing polyethylene terephthalate fibers with reduced flammability.
Still another object was to provide a masterbatch of polyethylene terephthalate with reduced flammability for the production of polyethylene terephthalate fibers by melt mixing and melt spinning.
SUMMARY OF THE INVENTION
The objects of the present invention could be achieved by a process for producing a polyethylene terephthalate fiber comprising the steps of:
(a) condensating at terephthalic acid and ethylene glycol in a molar ratio of from 1:1.1-1.5 at a temperature of from 180° to 240° C. in the presence of a catalyst;
(b) adding a polyalkylene glycol phosphate ester; and
(c) polycondensating at a temperature of from 265°-300° C. under a pressure decreasing from 760 torr to less than 2 torr to form the polyethylene terephthalate; and
(d) melt spinning fibers.
DETAILED DESCRIPTION OF THE INVENTION
The preparation of aromatic thermoplastic polyester is well known in the art and described for example in U.S. Pat. Nos. 4,517,355 and 4,981,945.
In step (a) terephthalic acid and ethylene glycol is condensated in a molar ratio of from about 1:1.1-1.5 at a temperature beginning from about 180° C. to a temperature of about 260° C. for a time period of up to about 2 to 3 hours in the presence of a catalyst, such as metal oxides or organic or inorganic metal salts, like antimony trioxide, germanium dioxide, manganese acetate, cobalt acetate and zinc acetate.
The catalyst content is from about 50 to 400 ppm based on the respective metal.
In a preferred embodiment of this invention this first step (a) is conducted using lower alkyl ester of terephthalic acid instead of terephthalic acid. Preferred is dimethyl terephthalate, whereby the formed methanol is distilled off the condensation reaction during the reaction time of from about 2 to about 3 hours.
At this point of the reaction the polyalkylene glycol phosphate ester is added as step (b).
The polyalkylene glycol phosphate ester of the present invention have the general formula: ##STR1## wherein n is a number of from 1 to 10
m is a number of from 0 to 3
R is H or C 1 -to-C 18 -alkyl radical.
Suitable polyalkylene glycol phosphate esters are for example tris (triethylene glycol) phosphate, tris (diethylene glycol) phosphate, and mixed tris (alkylene glycol) phosphates.
Preferred is tris (triethylene glycol) phosphate (TEGPa).
The phosphate ester is added in an amount of from about 0.4 to about 5.0% by weight, preferably from about 0.8 to about 1.6% by weight, based on the total weight of polyethylene terepthalate.
The condensation conditions are changed in step (c) to a temperature of from about 265 up to about 300° C., preferably 265 to 280° C with a pressure decreasing from 760 torr to less than 2 torr, preferably less than 1 torr, over a time period of from about 2 to 3 hours. During this time polycondensation occurs with the formation of a phosphate ester modified polyethylenene terephthalate having an intrinsic viscosity (IV) of from about 0.5 to about 0.7, preferably 0.55 to about 0.65. The phosphate ester is involved in the polycondensation by the reaction with its hydroxy or ester groups and forms a copolycondensation product of polyethylene terephthalate.
The amount of phosphorus in the final product for the manufacture of fibers with reduced flammability is from about 50 to about 2000 ppm, preferably from about 500 to about 1000 ppm phosphorus.
In a preferred embodiment of the present invention first a masterbatch of phosphate ester containing polyethylene terephthalate is produced containing from about 2000 to about 5000 ppm phosphorus. This master batch is mixed with fiber grade polyethylene terephthalate before processing into fibers by an extruder with spinnerette equipment.
In step (d) polyethylene terephthalate fibers are melt spun directly from the polymer melt of step (c) or from polyethylene terephthalate chips or granules, extruded from the polymer melt of step (c) or from the above-mentioned master batch, which is mixed with fiber grade polyethylene terephthalate.
The technique of fiber melt spinning is well known in the art, whereby the polyethylene terephthalate is fed into an extruder, in case of chips or granules melted and directed via Dowtherm heated polymer distribution lines to the spinning head. The polymer melt was then metered by a high efficiency gear pump to spin pack assembly and extruded through a spinnerette with a number of capillaries. The extruded filaments solidified, in a cross flow of chilled air. A finish based of lubrication oil and antistatic agents is then applied to the filament bundle for a proper processing performance. In the preferred technique, the filament bundle was drawn, textured and wound-up to form bulk continuous filament (BCF). The one-step technique of BCF manufacture is known in the trade as spin-draw-texturing (SDT). Two step technique which involves spinning and a subsequent texturing is also suitable for the manufacturing BCF of this invention.
The fibers show reduced flammability according to the vertical test method described in NFPA 701.
Other additives might be added to the fiber composition in effective amounts. Suitable additives are other flame retardants, UV-light stabilizers, antioxidants, pigments, dyes, antistatic agents, stain resistants, antimicrobial agents, nucleating agents and the like.
EXAMPLE
Synthesis of a master batch of modified polyethylene terephthalate
A mixture of dimethyl terephthalate (500 g), ethylene glycol (325 g), manganese acetate (0.1415 g) and antimony oxide (0.185 g) was heated while stirred under nitrogen. The temperature was raised from room temperature to 220° C. over a period of 2 hours. During the temperature rise, 160-170 ml of methanol is collected. After the methanol is removed the molten oligomer is cooled to 200° C. Tris (triethylene glycol) phosphate (25 g) (Emery 6696-A from Quantum Chemical Corporation, Emery Div.) was added to the molten oligomer and stirred for 5 min. The mixture was poured into the autoclave glass vessel and heated under decreasing pressure. The temperature was raised from 200° C. to 295° C. Excess ethylene glycol and some oligomers were removed, under vacuum, from the polymerizing mixture. The change in viscosity was visually observed and the polymer was extruded when the IV (intrinsic viscosity) of the polymer reached approximately 0.6. The analytical results show the phosphorous concentration was 0.48%.
EXAMPLE 1 (Control)
Fiber Spinning Procedure
21.2 lbs Polyethylene terephthalate (Polyester chips Ultradur® T-735, BASF AG, Ludwigshafen, Germany) were spun into fibers in a conventional manner with a standard melt spinning equipment at a speed of 1,600 m/min and then drawn at a rate of 647 m/min to give an elongation of 30% and tenacity of 4.5 g/denier.
EXAMPLE 2
Fiber Spinning Procedure
21.2 lbs Polyethylene terephthalate (Polyester chips Ultradur® T-735, BASF AG, Ludwigshafen, Germany) were tumble blended with the 4.2 lb master batch described above. The mixture was spun into fibers in a conventional manner with a standard melt spinning equipment at a speed of 1,600 m/min and then drawn at a rate of 647 m/min to give an elongation of 30% and tenacity of 4.5 g/denier.
Vertical Burn Test Procedure
Three pirns (three ends) of the drawn yarns, from Example 1 (control) and Example 2, were knit into a sock by a standard knitting machine. The socks were scoured, heat set at 375° C. and dried in a vacuum oven at 108° C. for three days. The phosphorous concentration in the yarn was 202 ppm. The socks were cut into 8"in length and two pieces from each Example were placed one on top of the other. The socks were mounted on a standard frame mentioned in the NFPA 701 test method. Vertical test method described in NFPA 701, Fire Tests for Flame-Resistant Textiles and Films, 1989, National Fire Protection Association Batterymarch Park, Quincy, Mass. 02269, was used to compare the flammability of Example 2 to that of the control. The average, burn time and the properties of Example 1 and Example 2 yarns are listed in the following table:
TABLE______________________________________ EXAMPLE 1 EXAMPLE 2 Burn Time (s) Burn Time (s)______________________________________ 53 2 77 1 48 0 76 1 30 0 73 1 63 2 106 1 71 1AVG 66.0 1.0DEN 151.0 150.0TEN 4.8 4.5ELN 27.0 30.0BWS 8.3 8.2CV 1.3 1.1IV 0.6 0.57______________________________________ AVG = Average DEN = Denier TEN = Tenacity ELN = Elongation BWS = Boiling water shrinkage CV = Evenness IV = Intrinsic Viscosity (1% solution in phenol/tetrachloroethane (60:40) at 25° C.)
The average burn time of the control (Example 1) was 66 seconds whereas the average burn time of the TEGPa containing sample (Example 2) was 1 sec. The physical properties of the TEGPa and the control samples are similar considering the fact the TEGPa samples were spun under the same conditions as the control.
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Disclosed is a process for producing polyethylene terephthalate fibers with reduced flammability which comprises the following steps:
(a) condensating terephthalic acid and ethylene glycol in a mole ratio of from 1:1.1-1.5 at a temperature of from 180°to 240° C. in the presence of a catalyst;
(b) adding a polyalkylene glycol phosphate ester;
(c) polycondensating at a temperature of from 265°-280° C. under a pressure decreasing from 760 torr to less than 2 torr to form the polyethylene terepthalate; and
(d) melt spinning fibers.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention generally relates to a cable connector assembly, and more particularly to a panel mount cable connector assembly.
[0003] 2. Description of Related Art
[0004] A panel mount cable connector assembly located in a chassis of a computer usually comprises an insulative housing, a plurality of conductive contacts received in the housing, a cable electrically connecting with the conductive contacts. A front portion of the insulative housing is configured to engage with a panel of a chassis and is exposed beyond the panel for engaging with a complementary connector. U.S. Pat. No. 6,030,242 discloses such a panel mount cable connector assembly. However, when the cable connector assembly needs to transmit high speed signals, grounding becomes an important issue. U.S. Pat. No. 5,975,958 discloses a panel mount connector engaging with a panel through a capacitive coupling adapter and electrically connecting with a printed circuit board in a chassis. Thus, the panel mount connector is grounded to resist against electromagnetic interference and discharge. However, the structure of the capacitive coupling adapter is relatively complex and cost consuming. In addition, the structure of the panel mount connector is not suitable for a panel mount cable connector assembly.
[0005] Hence, a cable connector assembly with improved grounding means is highly desired to overcome the disadvantages of the prior art.
SUMMARY OF THE INVENTION
[0006] Accordingly, an object of the present invention is to provide a cable connector assembly with better high speed signal transmitting effect.
[0007] In order to achieve the object set forth, a cable connector assembly in accordance with the present invention comprises an electrical connector comprising an insulative housing, a plurality of conductive contacts received in the insulative housing and a conductive shield attaching to the insulative housing, a cable comprising a plurality of lines, a printed circuit board electrically connecting the conductive contacts of the electrical connector with the lines of the cable, and a shielding member electrically connecting with the electrical connector and secured with the printed circuit board and the cable. The shielding member forms a plurality of deflecting members for securing to a panel and a plurality of anti-stress members for preventing the deflecting members from excessive deformation.
[0008] Other objects, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is an exploded, perspective view of a cable connector assembly in accordance with the present invention;
[0010] FIG. 2 is a view similar to FIG. 1 , but taken from a different aspect;
[0011] FIG. 3 is a partially assembled view of FIG. 1 ;
[0012] FIG. 4 is a view similar to FIG. 3 , but taken from a different aspect;
[0013] FIG. 5 is a partially assembled view of FIG. 3 ;
[0014] FIG. 6 is a view similar to FIG. 5 , but taken from a different aspect;
[0015] FIG. 7 is an assembled, perspective view of the cable connector assembly in accordance with the present invention; and
[0016] FIG. 8 is a view similar to FIG. 7 , but taken from a different aspect.
DETAILED DESCRIPTION OF THE INVENTION
[0017] Reference will now be made in detail to the preferred embodiment of the present invention.
[0018] Referring to FIGS. 1-2 , a cable connector assembly 100 in accordance with the present invention comprises an electrical connector 1 , a shielding member 2 surrounding the electrical connector 1 , a panel 3 , a printed circuit board 4 , a cable 5 , a band strip 6 , a pair of screw nuts 7 , a pair of screw bolts 8 and a pair of washers 9 .
[0019] Referring to FIGS. 1-2 in conjunction with FIGS. 7-8 , the electrical connector 1 comprises an insulative housing 10 , a plurality of conductive contacts 12 retained in the insulative housing 10 , and a conductive shield 11 enclosing the insulative housing 10 .
[0020] Particularly referring to FIG. 7 in conjunction with FIGS. 1-2 , the insulative housing 10 comprises a rectangular body portion 106 and a tongue portion 104 extending forwardly from the body portion 106 . A plurality of passageways 102 extend rearwardly from a front surface of the tongue portion 104 for receiving the conductive contacts 12 .
[0021] The conductive shield 11 comprises a first shield-half 110 and a second shield-half 112 engaging with the first shield-half 110 . The first shield-half 110 is configured as a substantially rectangular frame 1102 for engaging with a complementary connector. The second shield-half 112 comprises a main body 1120 enclosing the body portion 106 of the insulative housing 10 , a pair of curved retaining feet 1124 extending downwardly from opposite side walls of the main body 1120 and a rear part 1126 bending vertically from a top wall of the main body 1120 to enclose a rear face of the body portion 106 .
[0022] Each conductive contact 12 comprises a contacting portion (not labeled) received in a corresponding passageway 102 of the tongue portion 104 and a tail portion 120 bending vertically from the contacting portion and exposed beyond a bottom surface of the insulative housing 10 for electrically connecting with the printed circuit board 4 .
[0023] The shielding member 2 comprises an upper section 20 , a pair of opposite side sections 22 extending vertically from opposite sides of the upper section 20 , and a lower section 23 connecting with the pair of side sections 22 . A receiving space 24 is defined by the sections 20 , 22 , 23 . Each side section 22 forms a side latch 220 extending forwardly from a rear portion of the side section 22 . A U-shaped claw section 224 is formed at a front end of the side latch 220 . The U-shaped claw section 224 comprises a first and an opposite second sections 222 , 228 and an intermediate section 226 connecting with the first and the second sections 222 , 228 . The first and the second sections 222 , 228 and the intermediate section 226 thus, together define a U-shaped panel-receiving space 2240 . A pair of panel-retaining portions 21 extend vertically from a front edge of each of the upper and the lower sections 20 , 23 . Each panel-retaining portion 21 comprises a pair of anti-overstress members 210 and a deflecting member 212 located between the pair of anti-overstress members 210 and slightly bending rearwardly. The lower section 23 of the second conductive shield 2 is an enlarged flat piece and further defines a substantially rectangular opening 230 in a front portion thereof. A polarizing tab 236 ( FIG. 7 ) bends downwardly from a front edge of the opening 230 . A pair of first holes 232 and a pair of second holes 234 are respectively defined in the middle and a rear portion of the lower section 23 .
[0024] The panel 3 comprises a main body 30 comprising a first face 300 and an opposite second face 302 . A rectangular aperture 31 is defined in a middle of the main body 30 and a cutout 32 is defined in the main body to communicate with the aperture 31 .
[0025] The printed circuit board 4 is a rectangular board and forms a plurality of signal pads 42 adjacent to a rear edge thereof and a ground pad 44 located near the signal pads 42 . A pair of first ground vias 46 and a pair of second ground vias 48 are respectively defined in a rear portion and a front portion of the printed circuit board 4 and electrically connect with one another through a ground trace 43 . A plurality of signal vias 40 are defined in the middle of the printed circuit board 4 and respectively electrically with the signal pads 42 through a plurality of signal traces 41 . Each of the signal vias 40 and the ground vias 46 , 48 is formed by a through-hole coated with conductive material.
[0026] The cable 5 comprises a plurality of conductive conductors 52 and an insulating coating 50 enclosing the conductors 52 . The conductors 52 consist of a plurality of signal lines 520 and a ground line 522 corresponding to the signal and the ground pads 42 , 44 of the printed circuit board 4 .
[0027] In assembly, referring to FIGS. 1-4 in conjunction with FIGS. 7-8 , the conductive contacts 12 are respectively received in the passageways 102 of the insulative housing 10 with the tail portions 120 exposed beyond the bottom surface of the insulative housing 10 . The first and the second shield-halves 110 , 112 of the conductive shield 11 are assembled to the insulative housing 10 and engage with each other. The rear part 1126 encloses the rear face of the body portion 106 of the insulative housing 10 . Then the assembled electrical connector 1 is mounted on the printed circuit board 4 . The retaining feet 1124 of the conductive shield 11 are received in the pair of second ground vias 48 of the printed circuit board 4 and electrically connect with the ground pad 44 through the first ground vias 46 and the ground trace 43 . The tail portions 120 of the conductive contacts 12 are respectively received in the signal vias 40 and electrically connect with the signal pads 42 through the signal trace 41 . The signal and the ground lines 520 , 522 of the cable 5 are respectively soldered on the signal and the ground pads 42 , 44 of the printed circuit board 4 . Thus, the cable 5 electrically connects with the electrical connector 200 through the printed circuit board 4 .
[0028] Referring to FIGS. 5-8 , the electrical connector 1 , the printed circuit board 4 and the cable 5 is together assembled to the shielding member 2 . The electrical connector 1 is received in the receiving space 24 of the shielding member 2 with the printed circuit board 4 located upon the rectangular opening 230 . The cable 5 is located on a rear portion of the lower section 23 of the shielding member 2 with the band strip 6 protruding through the pair of second holes 234 of the lower section 23 to tie the cable 5 on the shielding member 2 . The pair of screw nuts 7 and the pair of washers 9 are respectively located on an upper surface of the printed circuit board 4 and a lower surface of the shielding member 2 and align with the pair of first ground vias 46 . The pair of screw bolts 8 respectively protrude through the first ground vias 46 and screw with the pair of screw nuts 7 . Therefore, the shielding member 2 is tightly secured with the printed circuit board 4 and the cable 5 .
[0029] Referring to FIGS. 7-8 in conjunction with FIGS. 1-3 , the shielding member 2 together with the electrical connector 1 , the printed circuit board 4 and the cable 5 is pulled to be assembled to the panel 3 in a front-to-back direction. The polarizing tab 236 can prevent the electrical connector 1 from being mounted to the panel 3 in a wrong direction. Finally, the panel 3 is received in the U-shaped panel-receiving spaces 2240 of the shielding member 2 with the deflecting members 212 and the first sections 222 of the claw sections 224 abutting on the first face 300 of the panel 3 . The second sections 228 of the claw sections 224 abut on the second face 203 of the panel 3 .
[0030] It is to be understood, however, that even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.
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A cable connector assembly ( 100 ) includes an electrical connector ( 1 ) including an insulative housing ( 10 ), a number of conductive contacts ( 12 ) received in the insulative housing and a conductive shield ( 11 ) enclosing the insulative housing, a cable ( 5 ) including a number of lines ( 520, 522 ), a printed circuit board ( 4 ) electrically connecting the conductive contacts of the electrical connector with the lines of the cable, and a shielding member ( 2 ) electrically connecting with the electrical connector and secured with the printed circuit board and the cable. The shielding member forms a number of deflecting members ( 212 ) for securing to a panel ( 3 ) and a number of anti-stress members for preventing the deflecting members from excessive deformation.
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